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Sample records for crenarchaeon pyrobaculum aerophilum

  1. Amylomaltase of Pyrobaculum aerophilum IM2 produces thermoreversible starch gels

    NARCIS (Netherlands)

    Kaper, T.; Talik, B.; Ettema, T.J.; Bos, H.; Maarel, M.J.E.C. van der; Dijkhuizen, L.

    2005-01-01

    Amylomaltases are 4-α-glucanotransferases (EC 2.4.1.25) of glycoside hydrolase family 77 that transfer α-1,4-linked glucans to another acceptor, which can be the 4-OH group of an α-1,4-linked glucan or glucose. The amylomaltase-encoding gene (PAE1209) from the hyperthermophilic archaeon Pyrobaculum

  2. Comparative Genomic and Transcriptional Analyses of CRISPR Systems Across the Genus Pyrobaculum

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    David L Bernick

    2012-07-01

    Full Text Available Within the domain Archaea, the CRISPR immune system appears to be nearly ubiquitous based on computational genome analyses. Initial studies in bacteria demonstrated that the CRISPR system targets invading plasmid and viral DNA. Recent experiments in the model archaeon Pyrococcus furiosus uncovered a novel RNA-targeting variant of the CRISPR system potentially unique to archaea. Because our understanding of CRISPR system evolution in other archaea is limited, we have taken a comparative genomic and transcriptomic view of the CRISPR arrays across six diverse species within the crenarchaeal genus Pyrobaculum. We present transcriptional data from each of four species in the genus (P. aerophilum, P. islandicum, P. calidifontis, P. arsenaticum, analyzing mature CRISPR-associated small RNA abundance from over 20 arrays. Within the genus, there is remarkable conservation of CRISPR array structure, as well as unique features that are have not been studied in other archaeal systems. These unique features include: a nearly invariant CRISPR promoter, conservation of direct repeat families, the 5' polarity of CRISPR-associated small RNA abundance, and a novel CRISPR-specific association with homologues of nurA and herA. These analyses provide a genus-level evolutionary perspective on archaeal CRISPR systems, broadening our understanding beyond existing non-comparative model systems.

  3. Pnserpin: A Novel Serine Protease Inhibitor from Extremophile Pyrobaculum neutrophilum

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    Huan Zhang

    2017-01-01

    Full Text Available Serine protease inhibitors (serpins are native inhibitors of serine proteases, constituting a large protein family with members spread over eukaryotes and prokaryotes. However, only very few prokaryotic serpins, especially from extremophiles, have been characterized to date. In this study, Pnserpin, a putative serine protease inhibitor from the thermophile Pyrobaculum neutrophilum, was overexpressed in Escherichia coli for purification and characterization. It irreversibly inhibits chymotrypsin-, trypsin-, elastase-, and subtilisin-like proteases in a temperature range from 20 to 100 °C in a concentration-dependent manner. The stoichiometry of inhibition (SI of Pnserpin for proteases decreases as the temperature increases, indicating that the inhibitory activity of Pnserpin increases with the temperature. SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that Pnserpin inhibits proteases by forming a SDS-resistant covalent complex. Homology modeling and molecular dynamic simulations predicted that Pnserpin can form a stable common serpin fold. Results of the present work will help in understanding the structural and functional characteristics of thermophilic serpin and will broaden the current knowledge about serpins from extremophiles.

  4. Genomic analysis of the symbiotic marine crenarchaeon, Cenarchaeumsymbiosum

    Energy Technology Data Exchange (ETDEWEB)

    Hallam, Steven J.; Konstantinidis, Konstantinos T.; Brochier,Celine; Putnam, Nik; Schleper, Christa; Watanabe, Yoh-ichi; Sugahara,Junichi; Preston, Christina; de la Torre, Jose; Richardson, Paul M.; DeLong, Edward F.

    2006-06-24

    Crenarchaea are ubiquitous and abundant microbial constituents of soils, sediments, lakes and ocean waters, yet relatively little is known about their fundamental evolutionary, ecological, and physiological properties. To better describe the ubiquitous nonthermophilic Crenarchaea, we analyzed the genome sequence of one representative, the uncultivated sponge symbiont, Cenarchaeum symbiosum. C. symbiosum genotypes coinhabiting the same host partitioned into two dominant populations, corresponding to previously described a- and b-type ribosomal RNA variants. Although synthetic, overlapping a- and b-type ribotypes harbored significant genetic variability. A single tiling path comprising the dominant a-type genotype was assembled, and used to explore the biological properties of C. symbiosum and its planktonic relatives. Out of a total of 2,066 predicted open reading frames, 36% were more highly conserved with other Archaea. The remainder partitioned between bacteria (18%), eukaryotes (1.5%) and viruses (0.1%). A total of 525 open reading frames were more highly conserved with sequences derived from marine environmental genomic surveys, most probably representing orthologous genes found in free-living planktonic Crenarchaea. The remaining genes partitioned between functional RNAs (2.4%), and hypotheticals (42%) with limited homology to known functional genes. The latter category likely contains genes specifically involved in mediated archaeal-sponge symbiosis. Phylogenetic analyses placed C. symbiosum as a basal crenarchaeon, sharing specific genomic features in common with either Crenarchaea, Euryarchaea, or both. The genome sequence of C. symbiosum reflect a unique and unusual evolutionary, physiological, and ecological history, one remarkably distinct from that of any other previously known microbial lineage.

  5. Pyrobaculum calidifontis sp. nov., a novel hyperthermophilic archaeon that grows in atmospheric air

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    Taku Amo

    2002-01-01

    Full Text Available A novel, facultatively aerobic, heterotrophic hyperthermophilic archaeon was isolated from a terrestrial hot spring in the Philippines. Cells of the new isolate, strain VA1, were rod-shaped with a length of 1.5 to 10 μm and a width of 0.5 to 1.0 μm. Isolate VA1 grew optimally at 90 to 95 °C and pH 7.0 under atmospheric air. Oxygen served as a final electron acceptor under aerobic growth conditions, and vigorous shaking of the medium significantly enhanced growth. Elemental sulfur inhibited cell growth under aerobic growth conditions, whereas thiosulfate stimulated cell growth. Under anaerobic growth conditions, nitrate served as a final electron acceptor, but nitrite or sulfur-containing compounds such as elemental sulfur, thiosulfate, sulfate and sulfite could not act as final electron acceptors. The G+C content of the genomic DNA was 51 mol%. Phylogenetic analysis based on 16S rRNA sequences indicated that strain VA1 exhibited close relationships to species of the genus Pyrobaculum. A DNA–DNA hybridization study revealed a low level of similarity (≤ 18% between strain VA1 and previously described members of the genus Pyrobaculum. Physiological characteristics also indicated that strain VA1 was distinct from these Pyrobaculum species. Our results indicate that isolate VA1 represents a novel species, named Pyrobaculum calidifontis.

  6. ORF Alignment: NC_003364 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available initiation factor IIB (TFIIB) [Pyrobaculum aerophilum ... str. IM2] ... Length = 52 ... Query: 2 ... TRKLIFELEEYACPACGAVNDVI...VDYERGQVICKSCGVVLKDGIADLGPEWR 53 ... TRKLIFELEEYACPACGAVNDVI...VDYERGQVICKSCGVVLKDGIADLGPEWR Sbjct: 1 ... TRKLIFELEEYACPACGAVNDVIVDYERGQVICKSCGVVLKDGIADLGPEWR 52

  7. A Novel Highly Thermostable Multifunctional Beta-Glycosidase from Crenarchaeon Acidilobus saccharovorans

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    Vadim M. Gumerov

    2015-01-01

    Full Text Available We expressed a putative β-galactosidase Asac_1390 from hyperthermophilic crenarchaeon Acidilobus saccharovorans in Escherichia coli and purified the recombinant enzyme. Asac_1390 is composed of 490 amino acid residues and showed high sequence similarity to family 1 glycoside hydrolases from various thermophilic Crenarchaeota. The maximum activity was observed at pH 6.0 and 93°C. The half-life of the enzyme at 90°C was about 7 hours. Asac_1390 displayed high tolerance to glucose and exhibits hydrolytic activity towards cellobiose and various aryl glucosides. The hydrolytic activity with p-nitrophenyl (pNP substrates followed the order pNP-β-D-galactopyranoside (328 U mg−1, pNP-β-D-glucopyranoside (246 U mg−1, pNP-β-D-xylopyranoside (72 U mg−1, and pNP-β-D-mannopyranoside (28 U mg−1. Thus the enzyme was actually a multifunctional β-glycosidase. Therefore, the utilization of Asac_1390 may contribute to facilitating the efficient degradation of lignocellulosic biomass and help enhance bioconversion processes.

  8. ORF Alignment: NC_003364 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available domains ... [Pyrobaculum aerophilum str. IM2] ... Length = 128 ... Query: 2 ... KCGEIASRPVITVTPDTPLEKAVELMADHD...VGILVLVDKENPKRVVGVLSERDIVRSLAG 61 ... KCGEIASRPVITVTPDTPLEKAVELMADHD...VGILVLVDKENPKRVVGVLSERDIVRSLAG Sbjct: 1 ... KCGEIASRPVITVTPDTPLEKAVELMADHDVGILVLVDKENPKRVVGVLSERDIVRSLAG 60 ... Query: 122 KRIGGLRK 129 ... KRIGGLRK Sbjct: 121 KRIGGLRK 128

  9. Development of the Multiple Gene Knockout System with One-Step PCR in Thermoacidophilic Crenarchaeon Sulfolobus acidocaldarius

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    Shoji Suzuki

    2017-01-01

    Full Text Available Multiple gene knockout systems developed in the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius are powerful genetic tools. However, plasmid construction typically requires several steps. Alternatively, PCR tailing for high-throughput gene disruption was also developed in S. acidocaldarius, but repeated gene knockout based on PCR tailing has been limited due to lack of a genetic marker system. In this study, we demonstrated efficient homologous recombination frequency (2.8 × 104 ± 6.9 × 103 colonies/μg DNA by optimizing the transformation conditions. This optimized protocol allowed to develop reliable gene knockout via double crossover using short homologous arms and to establish the multiple gene knockout system with one-step PCR (MONSTER. In the MONSTER, a multiple gene knockout cassette was simply and rapidly constructed by one-step PCR without plasmid construction, and the PCR product can be immediately used for target gene deletion. As an example of the applications of this strategy, we successfully made a DNA photolyase- (phr- and arginine decarboxylase- (argD- deficient strain of S. acidocaldarius. In addition, an agmatine selection system consisting of an agmatine-auxotrophic strain and argD marker was also established. The MONSTER provides an alternative strategy that enables the very simple construction of multiple gene knockout cassettes for genetic studies in S. acidocaldarius.

  10. Diversity of antisense and other non-coding RNAs in Archaea revealed by comparative small RNA sequencing in four Pyrobaculum species

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    David L Bernick

    2012-07-01

    Full Text Available A great diversity of small, non-coding RNA molecules with roles in gene regulation and RNA processing have been intensely studied in eukaryotic and bacterial model organisms, yet our knowledge of possible parallel roles for small RNAs in archaea is limited. We employed RNA-seq to identify novel small RNA across multiple species of the hyperthermophilic genus Pyrobaculum, known for unusual RNA gene characteristics. By comparing transcriptional data collected in parallel among four species, we were able to identify conserved RNA genes fitting into known and novel families. Among our findings, we highlight three novel cis-antisense small RNAs encoded opposite to key regulatory (ferric uptake regulator, metabolic (triose-phosphate isomerase, and core transcriptional apparatus genes (transcription factor B. We also found a large increase in the number of conserved C/D box small RNA genes over what had been previously recognized; many of these genes are encoded antisense to protein coding genes. The conserved opposition to orthologous genes across the Pyrobaculum genus suggests similarities to other cis-antisense regulatory systems. Furthermore, the genus-specific nature of these small RNAs indicates they are relatively recent, stable adaptations.

  11. Morphology and genome organization of the virus PSV of the hyperthermophilic archaeal genera Pyrobaculum and Thermoproteus: a novel virus family, the Globuloviridae.

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    Häring, Monika; Peng, Xu; Brügger, Kim; Rachel, Reinhard; Stetter, Karl O; Garrett, Roger A; Prangishvili, David

    2004-06-01

    A novel virus, termed Pyrobaculum spherical virus (PSV), is described that infects anaerobic hyperthermophilic archaea of the genera Pyrobaculum and Thermoproteus. Spherical enveloped virions, about 100 nm in diameter, contain a major multimeric 33-kDa protein and host-derived lipids. A viral envelope encases a superhelical nucleoprotein core containing linear double-stranded DNA. The PSV infection cycle does not cause lysis of host cells. The viral genome was sequenced and contains 28337 bp. The genome is unique for known archaeal viruses in that none of the genes, including that encoding the major structural protein, show any significant sequence matches to genes in public sequence databases. Exceptionally for an archaeal double-stranded DNA virus, almost all the recognizable genes are located on one DNA strand. The ends of the genome consist of 190-bp inverted repeats that contain multiple copies of short direct repeats. The two DNA strands are probably covalently linked at their termini. On the basis of the unusual morphological and genomic properties of this DNA virus, we propose to assign PSV to a new viral family, the Globuloviridae.

  12. Pyrobaculum Yellowstonensis Strain WP30 Respires On Elemental Sulfur And/or Arsenate in Circumneutral Sulfidic Sediments of Yellowstone National Park

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    Jay, Z.; Beam, Jake; Dohnalkova, Alice; Lohmayer, R.; Bodle, B.; Planer-Friedrich, B.; Romine, Margaret F.; Inskeep, William

    2015-09-15

    Thermoproteales populations (phylum Crenarchaeota) are abundant in high-25 temperature (>70° C) environments of Yellowstone National Park (YNP) and are important in mediating biogeochemical cycles of sulfur, arsenic and carbon. The objectives of this study were to determine specific physiological attributes of the isolate Pyrobaculum yellowstonensis strain WP30, which was obtained from an elemental sulfur sediment (Joseph’s Coat Hot Spring [JCHS]; 80 °C; pH 6.1), and relate this organism to geochemical processes occurring in situ. Strain WP30 is a chemoheterotroph that utilizes organic carbon as a source of carbon and electrons and requires elemental sulfur and/or arsenic as electron acceptors. Growth in the presence of elemental sulfur and arsenate resulted in the production of thioarsenates and polysulfides relative to sterile controls. The complete genome of this organism was sequenced (1.99 Mb, 58 % G+C) and revealed numerous metabolic pathways for the degradation of carbohydrates, amino acids and lipids, multiple dimethylsulfoxide molybdopterin (DMSO-MPT) oxidoreductase genes, which are implicated in the reduction of sulfur and arsenic, and pathways for the de novo synthesis of nearly all required cofactors and metabolites. Comparative genomics of P. yellowstonensis versus assembled metagenome sequence from JCHS showed that this organisms is highly-related (~95% average nucleotide identity) to in situ populations. The physiological attributes and metabolic capabilities of P. yellowstonensis provide importanat information towards understanding the distribution and function of these populations in YNP.

  13. Dicty_cDB: Contig-U11181-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available id:none) Pyrobaculum aerophilum str. IM2,... 94 2e-17 AM944373_1( AM944373 |pid:n...one) Propionibacterium freudenreichii s... 93 3e-17 CP001114_2205( CP001114 |pid:none) Deinococcus deserti V

  14. Crystal structure of the NADP+ and tartrate-bound complex of L-serine 3-dehydrogenase from the hyperthermophilic archaeon Pyrobaculum calidifontis.

    Science.gov (United States)

    Yoneda, Kazunari; Sakuraba, Haruhiko; Araki, Tomohiro; Ohshima, Toshihisa

    2018-05-01

    A gene encoding L-serine dehydrogenase (L-SerDH) that exhibits extremely low sequence identity to the Agrobacterium tumefaciens L-SerDH was identified in the hyperthermophilic archaeon Pyrobaculum calidifontis. The predicted amino acid sequence showed 36% identity with that of Pseudomonas aeruginosa L-SerDH, suggesting that P. calidifontis L-SerDH is a novel type of L-SerDH, like Ps. aeruginosa L-SerDH. The overexpressed enzyme appears to be the most thermostable L-SerDH described to date, and no loss of activity was observed by incubation for 30 min at temperatures up to 100 °C. The enzyme showed substantial reactivity towards D-serine, in addition to L-serine. Two different crystal structures of P. calidifontis L-SerDH were determined using the Se-MAD and MR method: the structure in complex with NADP + /sulfate ion at 1.18 Å and the structure in complex with NADP + /L-tartrate (substrate analog) at 1.57 Å. The fold of the catalytic domain showed similarity with that of Ps. aeruginosa L-SerDH. However, the active site structure significantly differed between the two enzymes. Based on the structure of the tartrate, L- and D-serine and 3-hydroxypropionate molecules were modeled into the active site and the substrate binding modes were estimated. A structural comparison suggests that the wide cavity at the substrate binding site is likely responsible for the high reactivity of the enzyme toward both L- and D-serine enantiomers. This is the first description of the structure of the novel type of L-SerDH with bound NADP + and substrate analog, and it provides new insight into the substrate binding mechanism of L-SerDH. The results obtained here may be very informative for the creation of L- or D-serine-specific SerDH by protein engineering.

  15. Structural studies of substrate and product complexes of 5-aminolaevulinic acid dehydratase from humans, Escherichia coli and the hyperthermophile Pyrobaculum calidifontis.

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    Mills-Davies, N; Butler, D; Norton, E; Thompson, D; Sarwar, M; Guo, J; Gill, R; Azim, N; Coker, A; Wood, S P; Erskine, P T; Coates, L; Cooper, J B; Rashid, N; Akhtar, M; Shoolingin-Jordan, P M

    2017-01-01

    A number of X-ray analyses of an enzyme involved in a key early stage of tetrapyrrole biosynthesis are reported. Two structures of human 5-aminolaevulinate dehydratase (ALAD), native and recombinant, have been determined at 2.8 Å resolution, showing that the enzyme adopts an octameric quaternary structure in accord with previously published analyses of the enzyme from a range of other species. However, this is in contrast to the finding that a disease-related F12L mutant of the human enzyme uniquely forms hexamers [Breinig et al. (2003), Nature Struct. Biol. 10, 757-763]. Monomers of all ALADs adopt the TIM-barrel fold; the subunit conformation that assembles into the octamer includes the N-terminal tail of one monomer curled around the (α/β) 8 barrel of a neighbouring monomer. Both crystal forms of the human enzyme possess two monomers per asymmetric unit, termed A and B. In the native enzyme there are a number of distinct structural differences between the A and B monomers, with the latter exhibiting greater disorder in a number of loop regions and in the active site. In contrast, the second monomer of the recombinant enzyme appears to be better defined and the active site of both monomers clearly possesses a zinc ion which is bound by three conserved cysteine residues. In native human ALAD, the A monomer also has a ligand resembling the substrate ALA which is covalently bound by a Schiff base to one of the active-site lysines (Lys252) and is held in place by an ordered active-site loop. In contrast, these features of the active-site structure are disordered or absent in the B subunit of the native human enzyme. The octameric structure of the zinc-dependent ALAD from the hyperthermophile Pyrobaculum calidifontis is also reported at a somewhat lower resolution of 3.5 Å. Finally, the details are presented of a high-resolution structure of the Escherichia coli ALAD enzyme co-crystallized with a noncovalently bound moiety of the product, porphobilinogen (PBG

  16. Respiration of arsenate and selenate by hyperthermophilic archaea.

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    Huber, R; Sacher, M; Vollmann, A; Huber, H; Rose, D

    2000-10-01

    A novel, strictly anaerobic, hyperthermophilic, facultative organotrophic archaeon was isolated from a hot spring at Pisciarelli Solfatara, Naples, Italy. The rod-shaped cells grew chemolithoautotrophically with carbon dioxide as carbon source, hydrogen as electron donor and arsenate, thiosulfate or elemental sulfur as electron acceptor. H2S was formed from sulfur or thiosulfate, arsenite from arsenate. Organotrophically, the new isolate grew optimally in the presence of an inorganic electron acceptor like sulfur, selenate or arsenate. Cultures, grown on arsenate and thiosulfate or arsenate and L-cysteine, precipitated realgar (As2S2). During growth on selenate, elemental selenium was produced. The G+C content of the DNA was 58.3 mol%. Due to 16S rRNA gene sequence analysis combined with physiological and morphological criteria, the new isolate belongs to the Thermoproteales order. It represents a new species within the genus Pyrobaculum, the type species of which we name Pyrobaculum arsenaticum (type strain PZ6*, DSM 13514, ATCC 700994). Comparative studies with different Pyrobaculum-species showed, that Pyrobaculum aerophilum was also able to grow organotrophically under anaerobic culture conditions in the presence of arsenate, selenate and selenite. During growth on selenite, elemental selenium was formed as final product. In contrast to P. arsenaticum, P. aerophilum could use selenate or arsenate for lithoautotrophic growth with carbon dioxide and hydrogen.

  17. JGEN-D-15-00296R2_MOESM3_ESM.xls

    Indian Academy of Sciences (India)

    SSS

    5, Crenarchaea, Hyperthermus butylicus DSM 5456, 0.139, 51.15, 54.2, 0.224, 47.32, 50.21, -0.085, 3.83, 3.99. 6, Crenarchaea, Metallosphaera sedula DSM 5348, 0.109, 51.62, 52.99, 0.137, 51.08, 50.47, -0.028, 0.54, 2.52. 7, Crenarchaea, Pyrobaculum aerophilum str. IM2, 0.145, 52.89, 54.34, 0.152, 52.53, 53.87, -0.007 ...

  18. Engineering and Characterization of a Superfolder Green Fluorescent Protein

    International Nuclear Information System (INIS)

    Pedelacq, J.; Cabantous, S.; Tran, T.; Terwilliger, T.; Waldo, G.

    2006-01-01

    Existing variants of green fluorescent protein (GFP) often misfold when expressed as fusions with other proteins. We have generated a robustly folded version of GFP, called 'superfolder' GFP, that folds well even when fused to poorly folded polypeptides. Compared to 'folding reporter' GFP, a folding-enhanced GFP containing the 'cycle-3' mutations and the 'enhanced GFP' mutations F64L and S65T, superfolder GFP shows improved tolerance of circular permutation, greater resistance to chemical denaturants and improved folding kinetics. The fluorescence of Escherichia coli cells expressing each of eighteen proteins from Pyrobaculum aerophilum as fusions with superfolder GFP was proportional to total protein expression. In contrast, fluorescence of folding reporter GFP fusion proteins was strongly correlated with the productive folding yield of the passenger protein. X-ray crystallographic structural analyses helped explain the enhanced folding of superfolder GFP relative to folding reporter GFP

  19. CC1, a novel crenarchaeal DNA binding protein.

    Science.gov (United States)

    Luo, Xiao; Schwarz-Linek, Uli; Botting, Catherine H; Hensel, Reinhard; Siebers, Bettina; White, Malcolm F

    2007-01-01

    The genomes of the related crenarchaea Pyrobaculum aerophilum and Thermoproteus tenax lack any obvious gene encoding a single-stranded DNA binding protein (SSB). SSBs are essential for DNA replication, recombination, and repair and are found in all other genomes across the three domains of life. These two archaeal genomes also have only one identifiable gene encoding a chromatin protein (the Alba protein), while most other archaea have at least two different abundant chromatin proteins. We performed a biochemical screen for novel nucleic acid binding proteins present in cell extracts of T. tenax. An assay for proteins capable of binding to a single-stranded DNA oligonucleotide resulted in identification of three proteins. The first protein, Alba, has been shown previously to bind single-stranded DNA as well as duplex DNA. The two other proteins, which we designated CC1 (for crenarchaeal chromatin protein 1), are very closely related to one another, and homologs are restricted to the P. aerophilum and Aeropyrum pernix genomes. CC1 is a 6-kDa, monomeric, basic protein that is expressed at a high level in T. tenax. This protein binds single- and double-stranded DNAs with similar affinities. These properties are consistent with a role for CC1 as a crenarchaeal chromatin protein.

  20. NADP-Dependent Aldehyde Dehydrogenase from Archaeon Pyrobaculum sp.1860: Structural and Functional Features

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    Ekaterina Yu. Bezsudnova

    2016-01-01

    Full Text Available We present the functional and structural characterization of the first archaeal thermostable NADP-dependent aldehyde dehydrogenase AlDHPyr1147. In vitro, AlDHPyr1147 catalyzes the irreversible oxidation of short aliphatic aldehydes at 60–85°С, and the affinity of AlDHPyr1147 to the NADP+ at 60°С is comparable to that for mesophilic analogues at 25°С. We determined the structures of the apo form of AlDHPyr1147 (3.04 Å resolution, three binary complexes with the coenzyme (1.90, 2.06, and 2.19 Å, and the ternary complex with the coenzyme and isobutyraldehyde as a substrate (2.66 Å. The nicotinamide moiety of the coenzyme is disordered in two binary complexes, while it is ordered in the ternary complex, as well as in the binary complex obtained after additional soaking with the substrate. AlDHPyr1147 structures demonstrate the strengthening of the dimeric contact (as compared with the analogues and the concerted conformational flexibility of catalytic Cys287 and Glu253, as well as Leu254 and the nicotinamide moiety of the coenzyme. A comparison of the active sites of AlDHPyr1147 and dehydrogenases characterized earlier suggests that proton relay systems, which were previously proposed for dehydrogenases of this family, are blocked in AlDHPyr1147, and the proton release in the latter can occur through the substrate channel.

  1. Crystallization and preliminary X-ray analysis of membrane-bound pyrophosphatases.

    Science.gov (United States)

    Kellosalo, Juho; Kajander, Tommi; Honkanen, Riina; Goldman, Adrian

    2013-02-01

    Membrane-bound pyrophosphatases (M-PPases) are enzymes that enhance the survival of plants, protozoans and prokaryotes in energy constraining stress conditions. These proteins use pyrophosphate, a waste product of cellular metabolism, as an energy source for sodium or proton pumping. To study the structure and function of these enzymes we have crystallized two membrane-bound pyrophosphatases recombinantly produced in Saccharomyces cerevisae: the sodium pumping enzyme of Thermotoga maritima (TmPPase) and the proton pumping enzyme of Pyrobaculum aerophilum (PaPPase). Extensive crystal optimization has allowed us to grow crystals of TmPPase that diffract to a resolution of 2.6 Å. The decisive step in this optimization was in-column detergent exchange during the two-step purification procedure. Dodecyl maltoside was used for high temperature solubilization of TmPPase and then exchanged to a series of different detergents. After extensive screening, the new detergent, octyl glucose neopentyl glycol, was found to be the optimal for TmPPase but not PaPPase.

  2. Isolation and Distribution of a Novel Iron-Oxidizing Crenarchaeon from Acidic Geothermal Springs in Yellowstone National Park▿ †

    Science.gov (United States)

    Kozubal, M.; Macur, R. E.; Korf, S.; Taylor, W. P.; Ackerman, G. G.; Nagy, A.; Inskeep, W. P.

    2008-01-01

    Novel thermophilic crenarchaea have been observed in Fe(III) oxide microbial mats of Yellowstone National Park (YNP); however, no definitive work has identified specific microorganisms responsible for the oxidation of Fe(II). The objectives of the current study were to isolate and characterize an Fe(II)-oxidizing member of the Sulfolobales observed in previous 16S rRNA gene surveys and to determine the abundance and distribution of close relatives of this organism in acidic geothermal springs containing high concentrations of dissolved Fe(II). Here we report the isolation and characterization of the novel, Fe(II)-oxidizing, thermophilic, acidophilic organism Metallosphaera sp. strain MK1 obtained from a well-characterized acid-sulfate-chloride geothermal spring in Norris Geyser Basin, YNP. Full-length 16S rRNA gene sequence analysis revealed that strain MK1 exhibits only 94.9 to 96.1% sequence similarity to other known Metallosphaera spp. and less than 89.1% similarity to known Sulfolobus spp. Strain MK1 is a facultative chemolithoautotroph with an optimum pH range of 2.0 to 3.0 and an optimum temperature range of 65 to 75°C. Strain MK1 grows optimally on pyrite or Fe(II) sorbed onto ferrihydrite, exhibiting doubling times between 10 and 11 h under aerobic conditions (65°C). The distribution and relative abundance of MK1-like 16S rRNA gene sequences in 14 acidic geothermal springs containing Fe(III) oxide microbial mats were evaluated. Highly related MK1-like 16S rRNA gene sequences (>99% sequence similarity) were consistently observed in Fe(III) oxide mats at temperatures ranging from 55 to 80°C. Quantitative PCR using Metallosphaera-specific primers confirmed that organisms highly similar to strain MK1 comprised up to 40% of the total archaeal community at selected sites. The broad distribution of highly related MK1-like 16S rRNA gene sequences in acidic Fe(III) oxide microbial mats is consistent with the observed characteristics and growth optima of Metallosphaera-like strain MK1 and emphasizes the importance of this newly described taxon in Fe(II) chemolithotrophy in acidic high-temperature environments of YNP. PMID:18083851

  3. Towards understanding the first genome sequence of a crenarchaeon by genome annotation using clusters of orthologous groups of proteins (COGs).

    Science.gov (United States)

    Natale, D A; Shankavaram, U T; Galperin, M Y; Wolf, Y I; Aravind, L; Koonin, E V

    2000-01-01

    Standard archival sequence databases have not been designed as tools for genome annotation and are far from being optimal for this purpose. We used the database of Clusters of Orthologous Groups of proteins (COGs) to reannotate the genomes of two archaea, Aeropyrum pernix, the first member of the Crenarchaea to be sequenced, and Pyrococcus abyssi. A. pernix and P. abyssi proteins were assigned to COGs using the COGNITOR program; the results were verified on a case-by-case basis and augmented by additional database searches using the PSI-BLAST and TBLASTN programs. Functions were predicted for over 300 proteins from A. pernix, which could not be assigned a function using conventional methods with a conservative sequence similarity threshold, an approximately 50% increase compared to the original annotation. A. pernix shares most of the conserved core of proteins that were previously identified in the Euryarchaeota. Cluster analysis or distance matrix tree construction based on the co-occurrence of genomes in COGs showed that A. pernix forms a distinct group within the archaea, although grouping with the two species of Pyrococci, indicative of similar repertoires of conserved genes, was observed. No indication of a specific relationship between Crenarchaeota and eukaryotes was obtained in these analyses. Several proteins that are conserved in Euryarchaeota and most bacteria are unexpectedly missing in A. pernix, including the entire set of de novo purine biosynthesis enzymes, the GTPase FtsZ (a key component of the bacterial and euryarchaeal cell-division machinery), and the tRNA-specific pseudouridine synthase, previously considered universal. A. pernix is represented in 48 COGs that do not contain any euryarchaeal members. Many of these proteins are TCA cycle and electron transport chain enzymes, reflecting the aerobic lifestyle of A. pernix. Special-purpose databases organized on the basis of phylogenetic analysis and carefully curated with respect to known and predicted protein functions provide for a significant improvement in genome annotation. A differential genome display approach helps in a systematic investigation of common and distinct features of gene repertoires and in some cases reveals unexpected connections that may be indicative of functional similarities between phylogenetically distant organisms and of lateral gene exchange.

  4. CrRNA-Protospacer Recognition during CRISPR- Directed DNA Interference Sulfolobus islandicus REY 15A and Structural Studies of CRISPR Binding Proteins (CBP) of Crenarchaeon Sulfolobus

    DEFF Research Database (Denmark)

    Mousaei, Marzieh

    The CRISPR-Cas (clustered regularly interspaced short palindromic repeats and associated proteins) is one of the important known immune mechanisms in archaea and bacteria. This adaptive immune system degrades invading genetic elements and protects the cell. Amongst 3 main types I, II and III...... of CRISPR system, two types (I and III) are found in archaea. However, in Sulfolobus species, subtypes IA, I-D, and III-B, III-D and rarely III-A are found. The model organism used for interference and structural studies is S. islandicus REY15A which carries subtypes I-A and III-B (α and β). Besides CRISPR...... ribonucleoprotein complex which is involved directly in defense, there are some less- known parts of the system including CPBs (CRISPR repeat-binding proteins) which are suggested to play a role in transcription. In the first part of my thesis, I provide a brief introduction to archaea and viruses that infect...

  5. Expression of Genes Involved in Iron and Sulfur Respiration in a Novel Thermophilic Crenarchaeon Isolated from Acid-Sulfate-Chloride Geothermal Systems

    Science.gov (United States)

    Kozubal, M.; Macur, R.; Inskeep, W. P.

    2007-12-01

    Acidic geothermal springs within Yellowstone National Park (YNP) provide an excellent opportunity to study microbial populations and their relationship with geochemical processes such as redox cycling and biomineralization of iron. Fourteen acid-sulfate-chloride (ASC) and acid-sulfate (AS) geothermal springs located in (YNP) have been extensively characterized for aqueous chemistry, solid phase mineral deposition and microbial diversity and distribution. The oxidation of Fe(II) with oxygen as an electron acceptor is exergonic under these conditions, consequently, Fe(II) may be an important electron donor driving primary production in ASC and AS habitats, and products of biomineralization (e.g. Fe[III]-oxides of varying crystallinity and structure, as well as jarosite in some cases) are common in the outflow channels of these environments. Recently, we isolated a novel Metallosphaera-like microorganism (Metallosphaera strain MK1) from an ASC spring in Norris Geyser Basin, YNP. Clone libraries (16S rRNA gene) from multiple sites suggest that microorganisms closely related to strain MK1 (between 98-100 percent similarity) dominate many spring locations between 55-80 C. The in situ abiotic oxidation rate of Fe(II) has been shown to be very slow in these systems and Metallosphaera strain MK1 has been directly implicated in biotic Fe(II) oxidation. Metallosphaera strain MK1 has been submitted for full genome sequencing and is yielding gene sequences related to the terminal oxidases SOXABC and SOXM super-complex. In addition, sequences from a recently characterized terminal oxidase FOX complex involved in Fe(II) and pyrite oxidation from Sulfolobus metallicus have been found in Metallosphaera strain MK1. A protein complex analogous to Metallosphaera sedula has been identified in strain MK1 and this complex has also been expressed in cells grown on pyrite and Fe(II). Other sequences identified in Metallosphaera strain MK1 that are involved in respiration are the TQO complex (thiosulfate:quinone oxidoreductase) related to the Acidianus ambivalens DOXAD complex and a sulfur reductase (SRE) complex related to one found in Sulfolobus solfataricus and Acidianus ambivalens. Here we report on the RNA expression of seven gene sequences from each of the above mentioned complexes for Metallosphaera strain MK1 grown aerobically on pyrite, sulfur, Fe(II)-ferrihydrite, and anaerobically with yeast extract and sulfur. In addition, expression studies are also compared to in situ samples collected from the geothermal Fe-mats.

  6. ORF Alignment: NC_003364 [GENIUS II[Archive

    Lifescience Database Archive (English)

    Full Text Available ... aerophilum str. IM2] ... Length = 291 ... Query: 25 ... AYLGFEPLWPIHIGWLIWAYKLAELKEAGFDVIVLVATWHAWIND...KGSIEELRAHGERVR 84 ... AYLGFEPLWPIHIGWLIWAYKLAELKEAGFDVIVLVATWHAWINDKGS...IEELRAHGERVR Sbjct: 1 ... AYLGFEPLWPIHIGWLIWAYKLAELKEAGFDVIVLVATWHAWINDKGSIEELRAHGERVR 60 ... Query: 145 MYPLMQVA

  7. Metagenomic Analysis of Hot Springs in Central India Reveals Hydrocarbon Degrading Thermophiles and Pathways Essential for Survival in Extreme Environments

    Science.gov (United States)

    Saxena, Rituja; Dhakan, Darshan B.; Mittal, Parul; Waiker, Prashant; Chowdhury, Anirban; Ghatak, Arundhuti; Sharma, Vineet K.

    2017-01-01

    Extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. India harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. The aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central India namely, Badi Anhoni, Chhoti Anhoni, and Tattapani at two geographically distinct regions (Anhoni and Tattapani), to uncover the resident microbial community and their metabolic traits. Samples were collected from seven distinct sites of the three hot spring locations with temperature ranging from 43.5 to 98°C. The 16S rRNA gene amplicon sequencing of V3 hypervariable region and shotgun metagenome sequencing uncovered a unique taxonomic and metabolic diversity of the resident thermophilic microbial community in these hot springs. Genes associated with hydrocarbon degradation pathways, such as benzoate, xylene, toluene, and benzene were observed to be abundant in the Anhoni hot springs (43.5–55°C), dominated by Pseudomonas stutzeri and Acidovorax sp., suggesting the presence of chemoorganotrophic thermophilic community with the ability to utilize complex hydrocarbons as a source of energy. A high abundance of genes belonging to methane metabolism pathway was observed at Chhoti Anhoni hot spring, where methane is reported to constitute >80% of all the emitted gases, which was marked by the high abundance of Methylococcus capsulatus. The Tattapani hot spring, with a high-temperature range (61.5–98°C), displayed a lower microbial diversity and was primarily dominated by a nitrate-reducing archaeal species Pyrobaculum aerophilum. A higher abundance of cell metabolism pathways essential for the microbial survival in extreme conditions was observed at Tattapani. Taken together

  8. Reverse gyrase functions in genome integrity maintenance by protecting DNA breaks in vivo

    DEFF Research Database (Denmark)

    Han, Wenyuan; Feng, Xu; She, Qunxin

    2017-01-01

    Reverse gyrase introduces positive supercoils to circular DNA and is implicated in genome stability maintenance in thermophiles. The extremely thermophilic crenarchaeon Sulfolobus encodes two reverse gyrase proteins, TopR1 (topoisomerase reverse gyrase 1) and TopR2, whose functions in thermophilic...... and subsequent DNA degradation. The former occurred immediately after drug treatment, leading to chromosomal DNA degradation that concurred with TopR1 degradation, followed by chromatin protein degradation and DNA-less cell formation. To gain a further insight into TopR1 function, the expression of the enzyme...

  9. Genetic determinants of PAM-dependent DNA targeting and pre-crRNA processing in Sulfolobus islandicus

    DEFF Research Database (Denmark)

    Peng, Wenfang; Li, Huan; Hallstrøm, Søren

    2013-01-01

    -adjacent motif (PAM)-dependent DNA targeting activity and mature CRISPR RNA (crRNA) production in this organism, mutants deleting individual genes of the type IA system or removing each of other Cas modules were constructed. Characterization of these mutants revealed that Cas7, Cas5, Cas6, Cas3' and Cas3......" are essential for PAM-dependent DNA targeting activity, whereas Csa5, along with all other Cas modules, is dispensable for the targeting in the crenarchaeon. Cas6 is implicated as the only enzyme for pre-crRNA processing and the crRNA maturation is independent of the DNA targeting activity. Importantly, we show...

  10. C68 from the Sulfolobus islandicus plasmid-virus pSSVx is a novel member of the AbrB-like transcription factor family

    DEFF Research Database (Denmark)

    Contursi, Patrizia; D'Ambrosio, Katia; Pirone, Luciano

    2011-01-01

    The genetic element pSSVx from Sulfolobus islandicus, strain REY15/4, is a hybrid between a plasmid and a fusellovirus. This plasmid-virus hybrid infects several species of the hyperthermophilic acidophilic crenarchaeon Sulfolobus. The open reading frame orfc68 of pSSVx encodes a 7.7 kDa protein...... factors, such as AbrB from Bacillus subtilis. Nevertheless, C68 constitutes a novel representative of this family because it shows several peculiar structural and functional features....

  11. Exceptional thermal stability and organic solvent tolerance of an esterase expressed from a thermophilic host

    DEFF Research Database (Denmark)

    Mei, Yuxia; Peng, Nan; Zhao, Shumiao

    2012-01-01

    , giving SisEstA. Upon Escherichia coli expression, only the thioredoxin-tagged EstA recombinant protein was soluble. The fusion protein was then purified, and removing the protein tag yielded EcSisEstA. Both forms of the thermophilic EstA enzyme were characterized. We found that SisEstA formed dimer...... that of EcSisEstA at 90°C. This indicated that thermophilic enzymes yielded from homologous expression should be better biocatalysts than those obtained from mesophilic expression.......A protein expression system recently developed for the thermophilic crenarchaeon Sulfolobus islandicus was employed to produce recombinant protein for EstA, a thermophilic esterase encoded in the same organism. Large amounts of protein were readily obtained by an affinity protein purification...

  12. The Distribution, Diversity, and Geobiology of Thermoproteales Populations in Yellowstone National Park

    Science.gov (United States)

    Jay, Z.; Beam, J.; Bailey, C.; Dohnalkova, A.; Planer-Friedrich, B.; Romine, M.; Inskeep, W. P.

    2012-12-01

    The order Thermoproteales (phylum Crenarchaeota) consists of thermophilic, rod-shaped organisms that are found globally in geothermal habitats ranging in pH from ~3-9. Nearly all isolated Thermoproteales couple the respiration of inorganic sulfur species (e.g. elemental sulfur, thiosulfate, sulfate) to the oxidation of hydrogen or complex organic carbon. Prior 16S rRNA and metagenome analysis revealed four prominent Thermoproteales-like populations in hypoxic, sulfidic hot springs In Yellowstone National Park (YNP), WY, USA (Monarch Geyser [80° C, pH 4], Cistern Spring [76° C, pH 5] and Joseph's Coat Hot Spring [JCHS; 80° C, pH 6]). The objectives of this study were to 1) characterize and compare the indigenous Thermoproteales-like de novo assemblies identified from metagenomic sequence data available for geothermal systems across YNP, 2) determine the metabolic potential of the Thermoproteales-like populations and evaluate their role in the geochemical cycling of organic and inorganic constituents, and 3) contrast both the sequenced genome and growth physiology of the first Thermoproteales isolated from YNP ("Pyrobaculum yellowstonensis" strain WP30), to the indigenous Thermoproteales-like de novo assemblies. Sequences related to either Caldivirga or Vulcanisaeta spp. (Type I Thermoproteales) were identified in both aerobic and anaerobic habitats ranging in pH ~3 - 6. Thermoproteus or Pyrobaculum spp. (Type-II Thermoproteales) were identified in anoxic habitats, but were constrained to pH values >4. Annotation of the de novo assemblies indicate that both Type-I and Type-II Thermoproteales populations are primarily heterotrophic, although key proteins of the autotrophic dicarboxylate/4-hydroxybutyrate cycle were also identified. Caldivirga/Vulcanisaeta-like populations appear to respire on elemental sulfur, sulfate, or molecular oxygen, while the Thermoproteus/Pyrobaculum-like population may also oxidize hydrogen and respire on elemental sulfur, thiosulfate

  13. Biochemical characterization of a recombinant short-chain NAD(H)-dependent dehydrogenase/reductase from Sulfolobus acidocaldarius.

    Science.gov (United States)

    Pennacchio, Angela; Giordano, Assunta; Pucci, Biagio; Rossi, Mosè; Raia, Carlo A

    2010-03-01

    The gene encoding a novel alcohol dehydrogenase that belongs to the short-chain dehydrogenases/reductases (SDRs) superfamily was identified in the aerobic thermoacidophilic crenarchaeon Sulfolobus acidocaldarius strain DSM 639. The saadh gene was heterologously overexpressed in Escherichia coli, and the protein (SaADH) was purified to homogeneity and characterized. SaADH is a tetrameric enzyme consisting of identical 28,978-Da subunits, each composed of 264 amino acids. The enzyme has remarkable thermophilicity and thermal stability, displaying activity at temperatures up to 75 degrees C and a 30-min half-inactivation temperature of ~90 degrees C, and shows good tolerance to common organic solvents. SaADH has a strict requirement for NAD(H) as the coenzyme, and displays a preference for the reduction of alicyclic, bicyclic and aromatic ketones and alpha-keto esters, but is poorly active on aliphatic, cyclic and aromatic alcohols, and shows no activity on aldehydes. The enzyme catalyses the reduction of alpha-methyl and alpha-ethyl benzoylformate, and methyl o-chlorobenzoylformate with 100% conversion to methyl (S)-mandelate [17% enantiomeric excess (ee)], ethyl (R)-mandelate (50% ee), and methyl (R)-o-chloromandelate (72% ee), respectively, with an efficient in situ NADH-recycling system which involves glucose and a thermophilic glucose dehydrogenase. This study provides further evidence supporting the critical role of the D37 residue in discriminating NAD(H) from NAD(P)H in members of the SDR superfamily.

  14. Biochemical and structural characterization of Cren7, a novel chromatin protein conserved among Crenarchaea.

    Science.gov (United States)

    Guo, Li; Feng, Yingang; Zhang, Zhenfeng; Yao, Hongwei; Luo, Yuanming; Wang, Jinfeng; Huang, Li

    2008-03-01

    Archaea contain a variety of chromatin proteins consistent with the evolution of different genome packaging mechanisms. Among the two main kingdoms in the Archaea, Euryarchaeota synthesize histone homologs, whereas Crenarchaeota have not been shown to possess a chromatin protein conserved at the kingdom level. We report the identification of Cren7, a novel family of chromatin proteins highly conserved in the Crenarchaeota. A small, basic, methylated and abundant protein, Cren7 displays a higher affinity for double-stranded DNA than for single-stranded DNA, constrains negative DNA supercoils and is associated with genomic DNA in vivo. The solution structure and DNA-binding surface of Cren7 from the hyperthermophilic crenarchaeon Sulfolobus solfataricus were determined by NMR. The protein adopts an SH3-like fold. It interacts with duplex DNA through a beta-sheet and a long flexible loop, presumably resulting in DNA distortions through intercalation of conserved hydrophobic residues into the DNA structure. These data suggest that the crenarchaeal kingdom in the Archaea shares a common strategy in chromatin organization.

  15. The Sso7d protein of Sulfolobus solfataricus: in vitro relationship among different activities

    Directory of Open Access Journals (Sweden)

    Annamaria Guagliardi

    2002-01-01

    Full Text Available The physiological role of the nonspecific DNA-binding protein Sso7d from the crenarchaeon Sulfolobus solfataricus is unknown. In vitro studies have shown that Sso7d promotes annealing of complementary DNA strands (Guagliardi et al. 1997, induces negative supercoiling (Lopez-Garcia et al. 1998, and chaperones the disassembly and renaturation of protein aggregates in an ATP hydrolysis-dependent manner (Guagliardi et al. 2000. In this study, we examined the relationships among the binding of Sso7d to double-stranded DNA, its interaction with protein aggregates, and its ATPase activity. Experiments with 1-anilinonaphthalene-8-sulfonic acid as probe demonstrated that exposed hydrophobic surfaces in Sso7d are responsible for interactions with protein aggregates and double-stranded DNA, whereas the site of ATPase activity has a non-hydrophobic character. The interactions of Sso7d with double-stranded DNA and with protein aggregates are mutually exclusive events, suggesting that the disassembly activity and the DNA-related activities of Sso7d may be competitive in vivo. In contrast, the hydrolysis of ATP by Sso7d is independent of the binding of Sso7d to double-stranded DNA or protein aggregates.

  16. Active methanotrophs in two contrasting North American peatland ecosystems revealed using DNA-SIP.

    Science.gov (United States)

    Gupta, Varun; Smemo, Kurt A; Yavitt, Joseph B; Basiliko, Nathan

    2012-02-01

    The active methanotroph community was investigated in two contrasting North American peatlands, a nutrient-rich sedge fen and nutrient-poor Sphagnum bog using in vitro incubations and (13)C-DNA stable-isotope probing (SIP) to measure methane (CH(4)) oxidation rates and label active microbes followed by fingerprinting and sequencing of bacterial and archaeal 16S rDNA and methane monooxygenase (pmoA and mmoX) genes. Rates of CH(4) oxidation were slightly, but significantly, faster in the bog and methanotrophs belonged to the class Alphaproteobacteria and were similar to other methanotrophs of the genera Methylocystis, Methylosinus, and Methylocapsa or Methylocella detected in, or isolated from, European bogs. The fen had a greater phylogenetic diversity of organisms that had assimilated (13)C, including methanotrophs from both the Alpha- and Gammaproteobacteria classes and other potentially non-methanotrophic organisms that were similar to bacteria detected in a UK and Finnish fen. Based on similarities between bacteria in our sites and those in Europe, including Russia, we conclude that site physicochemical characteristics rather than biogeography controlled the phylogenetic diversity of active methanotrophs and that differences in phylogenetic diversity between the bog and fen did not relate to measured CH(4) oxidation rates. A single crenarchaeon in the bog site appeared to be assimilating (13)C in 16S rDNA; however, its phylogenetic similarity to other CO(2)-utilizing archaea probably indicates that this organism is not directly involved in CH(4) oxidation in peat.

  17. Alterations of the transcriptome of Sulfolobus acidocaldarius by exoribonuclease aCPSF2.

    Directory of Open Access Journals (Sweden)

    Birgit Märtens

    Full Text Available Recent studies identified a 5´ to 3´ exoribonuclease termed Sso-RNase J in the crenarchaeon Sulfolobus solfataricus (Sso, which has been reclassified to the aCPSF2 (archaeal cleavage and polyadenylation specificity factor 2 group of β-CASP proteins. In this study, the Sso-aCPSF2 orthologue of Sulfolobus acidocaldarius (Saci-aCPSF2 was functionally characterized. Like Sso-aCPSF2, Saci-aCPSF2 degrades RNA with 5´ to 3´ directionality in vitro. To address the biological significance of Saci-aCPSF2, a deletion mutant was constructed, and the influence of Saci-aCPSF2 on the transcriptome profile was assessed employing high throughput RNA sequencing. This analysis revealed 560 genes with differential transcript abundance, suggesting a considerable role of this enzyme in RNA metabolism. In addition, bioinformatic analyses revealed several transcripts that are preferentially degraded at the 5´ end. This was exemplarily verified for two transcripts by Northern-blot analyses, showing for the first time that aCPSF2 proteins play a role in 5' to 3' directional mRNA decay in the crenarchaeal clade of Archaea.

  18. Two Family B DNA Polymerases From Aeropyrum pernix, Based on Revised Translational Frames

    Directory of Open Access Journals (Sweden)

    Katsuya Daimon

    2018-04-01

    Full Text Available Living organisms are divided into three domains, Bacteria, Eukarya, and Archaea. Comparative studies in the three domains have provided useful information to understand the evolution of the DNA replication machinery. DNA polymerase is the central enzyme of DNA replication. The presence of multiple family B DNA polymerases is unique in Crenarchaeota, as compared with other archaeal phyla, which have a single enzyme each for family B (PolB and family D (PolD. We analyzed PolB1 and PolB3 in the hyperthermophilic crenarchaeon, Aeropyrum pernix, and found that they are larger proteins than those predicted from the coding regions in our previous study and from public database annotations. The recombinant larger PolBs exhibited the same DNA polymerase activities as previously reported. However, the larger PolB3 showed remarkably higher thermostability, which made this enzyme applicable to PCR. In addition, the high tolerance to salt and heparin suggests that PolB3 will be useful for amplification from the samples with contaminants, and therefore it has a great potential for diagnostic use in the medical and environmental field.

  19. Molecular Characterization of Copper and Cadmium Resistance Determinants in the Biomining Thermoacidophilic Archaeon Sulfolobus metallicus

    Directory of Open Access Journals (Sweden)

    Alvaro Orell

    2013-01-01

    Full Text Available Sulfolobus metallicus is a thermoacidophilic crenarchaeon used in high-temperature bioleaching processes that is able to grow under stressing conditions such as high concentrations of heavy metals. Nevertheless, the genetic and biochemical mechanisms responsible for heavy metal resistance in S. metallicus remain uncharacterized. Proteomic analysis of S. metallicus cells exposed to 100 mM Cu revealed that 18 out of 30 upregulated proteins are related to the production and conversion of energy, amino acids biosynthesis, and stress responses. Ten of these last proteins were also up-regulated in S. metallicus treated in the presence of 1 mM Cd suggesting that at least in part, a common general response to these two heavy metals. The S. metallicus genome contained two complete cop gene clusters, each encoding a metallochaperone (CopM, a Cu-exporting ATPase (CopA, and a transcriptional regulator (CopT. Transcriptional expression analysis revealed that copM and copA from each cop gene cluster were cotranscribed and their transcript levels increased when S. metallicus was grown either in the presence of Cu or using chalcopyrite (CuFeS2 as oxidizable substrate. This study shows for the first time the presence of a duplicated version of the cop gene cluster in Archaea and characterizes some of the Cu and Cd resistance determinants in a thermophilic archaeon employed for industrial biomining.

  20. Antimicrobial activity of extracellular metabolites from antagonistic bacteria isolated from potato (Solanum phureja crops

    Directory of Open Access Journals (Sweden)

    Sinar David Granada García

    2014-09-01

    Full Text Available Microorganisms for biological control are capable of producing active compounds that inhibit the development of phytopathogens, constituting a promising tool toob tain active principles that could replace synthetic pesticides. This study evaluatedtheability of severalpotentialbiocontrol microorganismsto produce active extracellular metabolites. In vitro antagonistic capability of 50 bacterial isolates from rhizospheric soils of "criolla" potato (Solanum phureja was tested through dual culture in this plant with different plant pathogenic fungi and bacteria. Isolates that showed significantly higher antagonistic activity were fermented in liquid media and crude extracts from the supernatants had their biological activities assessed by optical density techniques. Inhibitory effecton tested pathogens was observed for concentrations between 0.5% and 1% of crude extracts. There was a correlation between the antimicrobial activity of extracts and the use of nutrient-rich media in bacteria fermentation. Using a bioguided method, a peptidic compound, active against Fusarium oxysporum, was obtained from the 7ANT04 strain (Pyrobaculum sp.. Analysis by nuclear magnetic resonance and liquid chromatography coupled to mass detector evidenced an 11-amino acid compound. Bioinformatic software using raw mass data confirmed the presence of a cyclic peptide conformed by 11 mostly non-standard amino acids.

  1. A virus of hyperthermophilic archaea with a unique architecture among DNA viruses.

    Science.gov (United States)

    Rensen, Elena Ilka; Mochizuki, Tomohiro; Quemin, Emmanuelle; Schouten, Stefan; Krupovic, Mart; Prangishvili, David

    2016-03-01

    Viruses package their genetic material in diverse ways. Most known strategies include encapsulation of nucleic acids into spherical or filamentous virions with icosahedral or helical symmetry, respectively. Filamentous viruses with dsDNA genomes are currently associated exclusively with Archaea. Here, we describe a filamentous hyperthermophilic archaeal virus, Pyrobaculum filamentous virus 1 (PFV1), with a type of virion organization not previously observed in DNA viruses. The PFV1 virion, 400 ± 20 × 32 ± 3 nm, contains an envelope and an inner core consisting of two structural units: a rod-shaped helical nucleocapsid formed of two 14-kDa major virion proteins and a nucleocapsid-encompassing protein sheath composed of a single major virion protein of 18 kDa. The virion organization of PFV1 is superficially similar to that of negative-sense RNA viruses of the family Filoviridae, including Ebola virus and Marburg virus. The linear dsDNA of PFV1 carries 17,714 bp, including 60-bp-long terminal inverted repeats, and contains 39 predicted ORFs, most of which do not show similarities to sequences in public databases. PFV1 is a lytic virus that completely disrupts the host cell membrane at the end of the infection cycle.

  2. Mono-, di- and trimethylated homologues of isoprenoid tetraether lipid cores in archaea and environmental samples: mass spectrometric identification and significance.

    Science.gov (United States)

    Knappy, Chris; Barillà, Daniela; Chong, James; Hodgson, Dominic; Morgan, Hugh; Suleman, Muhammad; Tan, Christine; Yao, Peng; Keely, Brendan

    2015-12-01

    Higher homologues of widely reported C(86) isoprenoid diglycerol tetraether lipid cores, containing 0-6 cyclopentyl rings, have been identified in (hyper)thermophilic archaea, representing up to 21% of total tetraether lipids in the cells. Liquid chromatography-tandem mass spectrometry confirms that the additional carbon atoms in the C(87-88) homologues are located in the etherified chains. Structures identified include dialkyl and monoalkyl ('H-shaped') tetraethers containing C(40-42) or C(81-82) hydrocarbons, respectively, many representing novel compounds. Gas chromatography-mass spectrometric analysis of hydrocarbons released from the lipid cores by ether cleavage suggests that the C(40) chains are biphytanes and the C(41) chains 13-methylbiphytanes. Multiple isomers, having different chain combinations, were recognised among the dialkyl lipids. Methylated tetraethers are produced by Methanothermobacter thermautotrophicus in varying proportions depending on growth conditions, suggesting that methylation may be an adaptive mechanism to regulate cellular function. The detection of methylated lipids in Pyrobaculum sp. AQ1.S2 and Sulfolobus acidocaldarius represents the first reported occurrences in Crenarchaeota. Soils and aquatic sediments from geographically distinct mesotemperate environments that were screened for homologues contained monomethylated tetraethers, with di- and trimethylated structures being detected occasionally. The structural diversity and range of occurrences of the C(87-89) tetraethers highlight their potential as complementary biomarkers for archaea in natural environments. Copyright © 2015 John Wiley & Sons, Ltd.

  3. The distribution, diversity, and importance of 16S rRNA gene introns in the order Thermoproteales.

    Science.gov (United States)

    Jay, Zackary J; Inskeep, William P

    2015-07-09

    Intron sequences are common in 16S rRNA genes of specific thermophilic lineages of Archaea, specifically the Thermoproteales (phylum Crenarchaeota). Environmental sequencing (16S rRNA gene and metagenome) from geothermal habitats in Yellowstone National Park (YNP) has expanded the available datasets for investigating 16S rRNA gene introns. The objectives of this study were to characterize and curate archaeal 16S rRNA gene introns from high-temperature habitats, evaluate the conservation and distribution of archaeal 16S rRNA introns in geothermal systems, and determine which "universal" archaeal 16S rRNA gene primers are impacted by the presence of intron sequences. Several new introns were identified and their insertion loci were constrained to thirteen locations across the 16S rRNA gene. Many of these introns encode homing endonucleases, although some introns were short or partial sequences. Pyrobaculum, Thermoproteus, and Caldivirga 16S rRNA genes contained the most abundant and diverse intron sequences. Phylogenetic analysis of introns revealed that sequences within the same locus are distributed biogeographically. The most diverse set of introns were observed in a high-temperature, circumneutral (pH 6) sulfur sediment environment, which also contained the greatest diversity of different Thermoproteales phylotypes. The widespread presence of introns in the Thermoproteales indicates a high probability of misalignments using different "universal" 16S rRNA primers employed in environmental microbial community analysis.

  4. Horizontal gene transfers with or without cell fusions in all categories of the living matter.

    Science.gov (United States)

    Sinkovics, Joseph G

    2011-01-01

    This article reviews the history of widespread exchanges of genetic segments initiated over 3 billion years ago, to be part of their life style, by sphero-protoplastic cells, the ancestors of archaea, prokaryota, and eukaryota. These primordial cells shared a hostile anaerobic and overheated environment and competed for survival. "Coexist with, or subdue and conquer, expropriate its most useful possessions, or symbiose with it, your competitor" remain cellular life's basic rules. This author emphasizes the role of viruses, both in mediating cell fusions, such as the formation of the first eukaryotic cell(s) from a united crenarchaeon and prokaryota, and the transfer of host cell genes integrated into viral (phages) genomes. After rising above the Darwinian threshold, rigid rules of speciation and vertical inheritance in the three domains of life were established, but horizontal gene transfers with or without cell fusions were never abolished. The author proves with extensive, yet highly selective documentation, that not only unicellular microorganisms, but the most complex multicellular entities of the highest ranks resort to, and practice, cell fusions, and donate and accept horizontally (laterally) transferred genes. Cell fusions and horizontally exchanged genetic materials remain the fundamental attributes and inherent characteristics of the living matter, whether occurring accidentally or sought after intentionally. These events occur to cells stagnating for some 3 milliard years at a lower yet amazingly sophisticated level of evolution, and to cells achieving the highest degree of differentiation, and thus functioning in dependence on the support of a most advanced multicellular host, like those of the human brain. No living cell is completely exempt from gene drains or gene insertions.

  5. Crystallization and preliminary X-ray crystallographic analysis of EstE1, a new and thermostable esterase cloned from a metagenomic library

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Jung-Sue [Department of Biology, Yonsei University, Seoul 120-749 (Korea, Republic of); Protein Network Research Center, Yonsei University, Seoul 120-749 (Korea, Republic of); Rhee, Jin-Kyu [Department of Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Dong-Uk [Department of Biology, Yonsei University, Seoul 120-749 (Korea, Republic of); Oh, Jong-Won [Department of Biotechnology, Yonsei University, Seoul 120-749 (Korea, Republic of); Cho, Hyun-Soo, E-mail: hscho8@yonsei.ac.kr [Department of Biology, Yonsei University, Seoul 120-749 (Korea, Republic of); Protein Network Research Center, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2006-02-01

    Recombinant EstE1 protein with a histidine tag at the C-terminus was overexpressed in Escherichia coli strain BL21(DE3) and then purified by affinity chromatography. The protein was then crystallized at 290 K by the hanging-drop vapour-diffusion method. EstE1, a new thermostable esterase, was isolated by functional screening of a metagenomic DNA library from thermal environment samples. This enzyme showed activity towards short-chain acyl derivatives of length C4–C6 at a temperature of 303–363 K and displayed a high thermostability above 353 K. EstE1 has 64 and 57% amino-acid sequence similarity to est{sub pc}-encoded carboxylesterase from Pyrobaculum calidifontis and AFEST from Archaeoglobus fulgidus, respectively. The recombinant protein with a histidine tag at the C-terminus was overexpressed in Escherichia coli strain BL21(DE3) and then purified by affinity chromatography. The protein was crystallized at 290 K by the hanging-drop vapour-diffusion method. X-ray diffraction data were collected to 2.3 Å resolution from an EstE1 crystal; the crystal belongs to space group P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 73.71, c = 234.23 Å. Assuming the presence of four molecules in the asymmetric unit, the Matthews coefficient V{sub M} is calculated to be 2.2 Å{sup 3} Da{sup −1} and the solvent content is 44.1%.

  6. Synthesis of 5-hydroxyectoine from ectoine: crystal structure of the non-heme iron(II and 2-oxoglutarate-dependent dioxygenase EctD.

    Directory of Open Access Journals (Sweden)

    Klaus Reuter

    2010-05-01

    Full Text Available As a response to high osmolality, many microorganisms synthesize various types of compatible solutes. These organic osmolytes aid in offsetting the detrimental effects of low water activity on cell physiology. One of these compatible solutes is ectoine. A sub-group of the ectoine producer's enzymatically convert this tetrahydropyrimidine into a hydroxylated derivative, 5-hydroxyectoine. This compound also functions as an effective osmostress protectant and compatible solute but it possesses properties that differ in several aspects from those of ectoine. The enzyme responsible for ectoine hydroxylation (EctD is a member of the non-heme iron(II-containing and 2-oxoglutarate-dependent dioxygenases (EC 1.14.11. These enzymes couple the decarboxylation of 2-oxoglutarate with the formation of a high-energy ferryl-oxo intermediate to catalyze the oxidation of the bound organic substrate. We report here the crystal structure of the ectoine hydroxylase EctD from the moderate halophile Virgibacillus salexigens in complex with Fe(3+ at a resolution of 1.85 A. Like other non-heme iron(II and 2-oxoglutarate dependent dioxygenases, the core of the EctD structure consists of a double-stranded beta-helix forming the main portion of the active-site of the enzyme. The positioning of the iron ligand in the active-site of EctD is mediated by an evolutionarily conserved 2-His-1-carboxylate iron-binding motif. The side chains of the three residues forming this iron-binding site protrude into a deep cavity in the EctD structure that also harbours the 2-oxoglutarate co-substrate-binding site. Database searches revealed a widespread occurrence of EctD-type proteins in members of the Bacteria but only in a single representative of the Archaea, the marine crenarchaeon Nitrosopumilus maritimus. The EctD crystal structure reported here can serve as a template to guide further biochemical and structural studies of this biotechnologically interesting enzyme family.

  7. Microbial Geochemistry in Shallow-Sea Hydrothermal Systems

    Science.gov (United States)

    Amend, J. P.; Pichler, T.

    2006-12-01

    Shallow-sea hydrothermal systems are far more ubiquitous than generally recognized. Approximately 50-60 systems are currently known, occurring world-wide in areas of high heat flow, such as, volcanic island arcs, near-surface mid-ocean ridges, and intraplate oceanic volcanoes. In contrast to deep-sea systems, shallow- sea vent fluids generally include a meteoric component, they experience phase separation near the sediment- water interface, and they discharge into the photic zone (thermophilic bacteria and archaea. Perhaps because deep-sea smokers and continental hot springs are visually more stunning, shallow-sea systems are often overlooked study sites. We will discuss their particular features that afford unique opportunities in microbial geochemistry. Two of the better studied examples are at Vulcano Island (Italy) and Ambitle Island (Papua New Guinea). The vents and sediment seeps at Vulcano are the "type locality" for numerous cultured hyperthermophiles, including the bacteria Aquifex and Thermotoga, the crenarchaeon Pyrodictium, and the Euryarchaeota Archaeoglobus and Pyrococcus. Isotope-labeled incubation experiments of heated sediments and an array of culturing studies have shown that simple organic compounds are predominantly fermented or anaerobically respired with sulfate. 16S rRNA gene surveys, together with fluorescent in situ hybridization studies, demonstrated the dominance of key thermophilic bacteria and archaea (e.g., Aquificales, Thermotogales, Thermococcales, Archaeoglobales) in the sediments and the presence of a broad spectrum of mostly uncultured crenarchaeota in several vent waters, sediment samples, and geothermal wells. Thermodynamic modeling quantified potential energy yields from aerobic and anaerobic respiration reactions and fermentation reactions. In contrast to their deep-sea counterparts, shallow-sea hydrothermal systems are often characterized by high arsenic concentrations of more than 500-times seawater levels. The arsenic

  8. Homology modeling of dissimilatory APS reductases (AprBA of sulfur-oxidizing and sulfate-reducing prokaryotes.

    Directory of Open Access Journals (Sweden)

    Birte Meyer

    Full Text Available BACKGROUND: The dissimilatory adenosine-5'-phosphosulfate (APS reductase (cofactors flavin adenine dinucleotide, FAD, and two [4Fe-4S] centers catalyzes the transformation of APS to sulfite and AMP in sulfate-reducing prokaryotes (SRP; in sulfur-oxidizing bacteria (SOB it has been suggested to operate in the reverse direction. Recently, the three-dimensional structure of the Archaeoglobus fulgidus enzyme has been determined in different catalytically relevant states providing insights into its reaction cycle. METHODOLOGY/PRINCIPAL FINDINGS: Full-length AprBA sequences from 20 phylogenetically distinct SRP and SOB species were used for homology modeling. In general, the average accuracy of the calculated models was sufficiently good to allow a structural and functional comparison between the beta- and alpha-subunit structures (78.8-99.3% and 89.5-96.8% of the AprB and AprA main chain atoms, respectively, had root mean square deviations below 1 A with respect to the template structures. Besides their overall conformity, the SRP- and SOB-derived models revealed the existence of individual adaptations at the electron-transferring AprB protein surface presumably resulting from docking to different electron donor/acceptor proteins. These structural alterations correlated with the protein phylogeny (three major phylogenetic lineages: (1 SRP including LGT-affected Archaeoglobi and SOB of Apr lineage II, (2 crenarchaeal SRP Caldivirga and Pyrobaculum, and (3 SOB of the distinct Apr lineage I and the presence of potential APS reductase-interacting redox complexes. The almost identical protein matrices surrounding both [4Fe-4S] clusters, the FAD cofactor, the active site channel and center within the AprB/A models of SRP and SOB point to a highly similar catalytic process of APS reduction/sulfite oxidation independent of the metabolism type the APS reductase is involved in and the species it has been originated from. CONCLUSIONS: Based on the comparative

  9. Hexavalent uranium reduction from solid phase by thermophilic bacterium Thermoterrabacterium ferrireducens

    International Nuclear Information System (INIS)

    Khijniak, T.V.; Slobodkin, A.I.; Bonch-Osmolovskaya, E.A.; Medvedeva-Lyalikova, N.N.; Coker, V.; Lloyd, J.R.; Birkeland, N.K.

    2005-01-01

    Full text of publication follows: It has been reported that in uranium-contaminated sites, solid-phase U(VI) present in sediments is resistant to microbial reduction. Also, it was demonstrated that mesophilic iron and sulfate-reducing bacteria can reduce hexavalent uranium and sulphate-reducing bacteria were able to grow via uranium reduction. Among thermophilic microorganisms reduction of hexavalent uranium has been demonstrated only for cell suspensions of two genera: Pyrobaculum and Thermus. In the present study, Thermoterrabacterium ferrireducens was tested for reduction of U(VI), a thermophilic, gram-positive anaerobic bacterium capable for growth with the reduction of various electron acceptors including Fe(III). Kinetic of bacterial growth, uranium reduction and influence of different uranium concentrations were investigated at 65 deg. C. Due to presence of phosphate in the basal medium yellow uranium phosphate precipitate was formed after addition of uranyl acetate. After 68 h of incubation control tubes without bacteria were contained yellow precipitate whereas in presence of bacteria precipitate turned to the grey color. In the control tubes uranium phosphates and other elements formed a uniform mixture of crystals, but in presence of bacteria the round shape particles, containing uranium, were found by Environmental Scan Electron Microscopy of air-dried or frozen samples. To determine valent state speciation spectroscopic investigations were performed also. Initial yellow uranium phosphate precipitate was separated and identified as uramphite - (NH 4 )(UO 2 )(PO 4 )*3H 2 O by X-Ray Powder Diffraction. Grey precipitate, which was formed by bacterial reduction, was identified as ningyoite - CaU(PO 4 ) 2 *H 2 O. The fact that final grey precipitate contain U(IV) was also confirmed by EXAFS investigation. High concentration of uranium has toxic effect. 1 and 2.5 mM of uranium (VI) support bacterial growth and bacterial biomass was accumulated, but if 5 or 10

  10. Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

    2001-01-01

    Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs

  11. A first insight into the occurrence and expression of functional amoA and accA genes of autotrophic and ammonia-oxidizing bathypelagic Crenarchaeota of Tyrrhenian Sea

    Science.gov (United States)

    Yakimov, Michail M.; Cono, Violetta La; Denaro, Renata

    2009-05-01

    The autotrophic and ammonia-oxidizing crenarchaeal assemblage at offshore site located in the deep Mediterranean (Tyrrhenian Sea, depth 3000 m) water was studied by PCR amplification of the key functional genes involved in energy (ammonia mono-oxygenase alpha subunit, amoA) and central metabolism (acetyl-CoA carboxylase alpha subunit, accA). Using two recently annotated genomes of marine crenarchaeons, an initial set of primers targeting archaeal accA-like genes was designed. Approximately 300 clones were analyzed, of which 100% of amoA library and almost 70% of accA library were unambiguously related to the corresponding genes from marine Crenarchaeota. Even though the acetyl-CoA carboxylase is phylogenetically not well conserved and the remaining clones were affiliated to various bacterial acetyl-CoA/propionyl-CoA carboxylase genes, the pool of archaeal sequences was applied for development of quantitative PCR analysis of accA-like distribution using TaqMan ® methodolgy. The archaeal accA gene fragments, together with alignable gene fragments from the Sargasso Sea and North Pacific Subtropical Gyre (ALOHA Station) metagenome databases, were analyzed by multiple sequence alignment. Two accA-like sequences, found in ALOHA Station at the depth of 4000 m, formed a deeply branched clade with 64% of all archaeal Tyrrhenian clones. No close relatives for residual 36% of clones, except of those recovered from Eastern Mediterranean, was found, suggesting the existence of a specific lineage of the crenarchaeal accA genes in deep Mediterranean water. Alignment of Mediterranean amoA sequences defined four cosmopolitan phylotypes of Crenarchaeota putative ammonia mono-oxygenase subunit A gene occurring in the water sample from the 3000 m depth. Without exception all phylotypes fell into Deep Marine Group I cluster that contain the vast majority of known sequences recovered from global deep-sea environment. Remarkably, three phylotypes accounted for 91% of all Mediterranean