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Novikova PV, Bhanu Busi S, Probst AJ, May P, Wilmes P. Functional prediction of proteins from the human gut archaeome. ISME COMMUNICATIONS 2024; 4:ycad014. [PMID: 38486809 PMCID: PMC10939349 DOI: 10.1093/ismeco/ycad014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 12/16/2023] [Accepted: 12/19/2023] [Indexed: 03/17/2024]
Abstract
The human gastrointestinal tract contains diverse microbial communities, including archaea. Among them, Methanobrevibacter smithii represents a highly active and clinically relevant methanogenic archaeon, being involved in gastrointestinal disorders, such as inflammatory bowel disease and obesity. Herein, we present an integrated approach using sequence and structure information to improve the annotation of M. smithii proteins using advanced protein structure prediction and annotation tools, such as AlphaFold2, trRosetta, ProFunc, and DeepFri. Of an initial set of 873 481 archaeal proteins, we found 707 754 proteins exclusively present in the human gut. Having analysed archaeal proteins together with 87 282 994 bacterial proteins, we identified unique archaeal proteins and archaeal-bacterial homologs. We then predicted and characterized functional domains and structures of 73 unique and homologous archaeal protein clusters linked the human gut and M. smithii. We refined annotations based on the predicted structures, extending existing sequence similarity-based annotations. We identified gut-specific archaeal proteins that may be involved in defense mechanisms, virulence, adhesion, and the degradation of toxic substances. Interestingly, we identified potential glycosyltransferases that could be associated with N-linked and O-glycosylation. Additionally, we found preliminary evidence for interdomain horizontal gene transfer between Clostridia species and M. smithii, which includes sporulation Stage V proteins AE and AD. Our study broadens the understanding of archaeal biology, particularly M. smithii, and highlights the importance of considering both sequence and structure for the prediction of protein function.
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Affiliation(s)
- Polina V Novikova
- Systems Ecology, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette L-4362, Luxembourg
| | - Susheel Bhanu Busi
- Systems Ecology, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette L-4362, Luxembourg
- UK Centre for Ecology and Hydrology, Wallingford, OX10 8 BB, United Kingdom
| | - Alexander J Probst
- Environmental Metagenomics, Department of Chemistry, Research Center One Health Ruhr of the University Alliance Ruhr, for Environmental Microbiology and Biotechnology, University Duisburg-Essen, Duisburg 47057, Germany
| | - Patrick May
- Bioinformatics Core, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette L-4362, Luxembourg
| | - Paul Wilmes
- Systems Ecology, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette L-4362, Luxembourg
- Department of Life Sciences and Medicine, Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette L-4362, Luxembourg
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2
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Wang YH, Dai H, Zhang L, Wu Y, Wang J, Wang C, Xu CH, Hou H, Yang B, Zhu Y, Zhang X, Zhou J. Cryo-electron microscopy structure and translocation mechanism of the crenarchaeal ribosome. Nucleic Acids Res 2023; 51:8909-8924. [PMID: 37604686 PMCID: PMC10516650 DOI: 10.1093/nar/gkad661] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 06/29/2023] [Accepted: 08/02/2023] [Indexed: 08/23/2023] Open
Abstract
Archaeal ribosomes have many domain-specific features; however, our understanding of these structures is limited. We present 10 cryo-electron microscopy (cryo-EM) structures of the archaeal ribosome from crenarchaeota Sulfolobus acidocaldarius (Sac) at 2.7-5.7 Å resolution. We observed unstable conformations of H68 and h44 of ribosomal RNA (rRNA) in the subunit structures, which may interfere with subunit association. These subunit structures provided models for 12 rRNA expansion segments and 3 novel r-proteins. Furthermore, the 50S-aRF1 complex structure showed the unique domain orientation of aRF1, possibly explaining P-site transfer RNA (tRNA) release after translation termination. Sac 70S complexes were captured in seven distinct steps of the tRNA translocation reaction, confirming conserved structural features during archaeal ribosome translocation. In aEF2-engaged 70S ribosome complexes, 3D classification of cryo-EM data based on 30S head domain identified two new translocation intermediates with 30S head domain tilted 5-6° enabling its disengagement from the translocated tRNA and its release post-translocation. Additionally, we observed conformational changes to aEF2 during ribosome binding and switching from three different states. Our structural and biochemical data provide new insights into archaeal translation and ribosome translocation.
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Affiliation(s)
- Ying-Hui Wang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Hong Dai
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Ling Zhang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yun Wu
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jingfen Wang
- Center for Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Department of Pathology of Sir Run Run Shaw Hospital, and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Chen Wang
- Center for Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Department of Pathology of Sir Run Run Shaw Hospital, and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Cai-Huang Xu
- Center for Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Department of Pathology of Sir Run Run Shaw Hospital, and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Hai Hou
- Institute of Medical Research, Northwestern Polytechnical University, Xi’an, Shaanxi 710072, China
| | - Bing Yang
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Yongqun Zhu
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xing Zhang
- Center for Cryo-Electron Microscopy, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
- Department of Pathology of Sir Run Run Shaw Hospital, and Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jie Zhou
- Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Archaea/eukaryote-specific ribosomal proteins - guardians of a complex structure. Comput Struct Biotechnol J 2023; 21:1249-1261. [PMID: 36817958 PMCID: PMC9932298 DOI: 10.1016/j.csbj.2023.01.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/09/2023] [Accepted: 01/26/2023] [Indexed: 01/29/2023] Open
Abstract
In three domains of life, proteins are synthesized by large ribonucleoprotein particles called ribosomes. All ribosomes are composed of ribosomal RNAs (rRNA) and numerous ribosomal proteins (r-protein). The three-dimensional shape of ribosomes is mainly defined by a tertiary structure of rRNAs. In addition, rRNAs have a major role in decoding the information carried by messenger RNAs and catalyzing the peptide bond formation. R-proteins are essential for shaping the network of interactions that contribute to a various aspects of the protein synthesis machinery, including assembly of ribosomes and interaction of ribosomal subunits. Structural studies have revealed that many key components of ribosomes are conserved in all life domains. Besides the core structure, ribosomes contain domain-specific structural features that include additional r-proteins and extensions of rRNA and r-proteins. This review focuses specifically on those r-proteins that are found only in archaeal and eukaryotic ribosomes. The role of these archaea/eukaryote specific r-proteins in stabilizing the ribosome structure is discussed. Several examples illustrate their functions in the formation of the internal network of ribosomal subunits and interactions between the ribosomal subunits. In addition, the significance of these r-proteins in ribosome biogenesis and protein synthesis is highlighted.
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4
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Yaeshima C, Murata N, Ishino S, Sagawa I, Ito K, Uchiumi T. A novel ribosome-dimerization protein found in the hyperthermophilic archaeon Pyrococcus furiosus using ribosome-associated proteomics. Biochem Biophys Res Commun 2022; 593:116-121. [DOI: 10.1016/j.bbrc.2022.01.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/12/2022] [Indexed: 12/30/2022]
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Jüttner M, Ferreira-Cerca S. A Comparative Perspective on Ribosome Biogenesis: Unity and Diversity Across the Tree of Life. Methods Mol Biol 2022; 2533:3-22. [PMID: 35796979 PMCID: PMC9761495 DOI: 10.1007/978-1-0716-2501-9_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Ribosomes are universally conserved ribonucleoprotein complexes involved in the decoding of the genetic information contained in messenger RNAs into proteins. Accordingly, ribosome biogenesis is a fundamental cellular process required for functional ribosome homeostasis and to preserve satisfactory gene expression capability.Although the ribosome is universally conserved, its biogenesis shows an intriguing degree of variability across the tree of life . These differences also raise yet unresolved questions. Among them are (a) what are, if existing, the remaining ancestral common principles of ribosome biogenesis ; (b) what are the molecular impacts of the evolution history and how did they contribute to (re)shape the ribosome biogenesis pathway across the tree of life ; (c) what is the extent of functional divergence and/or convergence (functional mimicry), and in the latter case (if existing) what is the molecular basis; (d) considering the universal ribosome conservation, what is the capability of functional plasticity and cellular adaptation of the ribosome biogenesis pathway?In this review, we provide a brief overview of ribosome biogenesis across the tree of life and try to illustrate some potential and/or emerging answers to these unresolved questions.
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Affiliation(s)
- Michael Jüttner
- Biochemistry III-Regensburg Center for Biochemistry-Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
| | - Sébastien Ferreira-Cerca
- Biochemistry III-Regensburg Center for Biochemistry-Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany.
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6
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Londei P, Ferreira-Cerca S. Ribosome Biogenesis in Archaea. Front Microbiol 2021; 12:686977. [PMID: 34367089 PMCID: PMC8339473 DOI: 10.3389/fmicb.2021.686977] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 05/14/2021] [Indexed: 12/02/2022] Open
Abstract
Making ribosomes is a major cellular process essential for the maintenance of functional ribosome homeostasis and to ensure appropriate gene expression. Strikingly, although ribosomes are universally conserved ribonucleoprotein complexes decoding the genetic information contained in messenger RNAs into proteins, their biogenesis shows an intriguing degree of variability across the tree of life. In this review, we summarize our knowledge on the least understood ribosome biogenesis pathway: the archaeal one. Furthermore, we highlight some evolutionary conserved and divergent molecular features of making ribosomes across the tree of life.
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Affiliation(s)
- Paola Londei
- Department of Molecular Medicine, University of Rome Sapienza, Rome, Italy
| | - Sébastien Ferreira-Cerca
- Biochemistry III - Regensburg Center for Biochemistry, Institute for Biochemistry, Genetics and Microbiology, University of Regensburg, Regensburg, Germany
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7
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Towards functional characterization of archaeal genomic dark matter. Biochem Soc Trans 2019; 47:389-398. [PMID: 30710061 PMCID: PMC6393860 DOI: 10.1042/bst20180560] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Revised: 01/08/2019] [Accepted: 01/09/2019] [Indexed: 01/07/2023]
Abstract
A substantial fraction of archaeal genes, from ∼30% to as much as 80%, encode ‘hypothetical' proteins or genomic ‘dark matter'. Archaeal genomes typically contain a higher fraction of dark matter compared with bacterial genomes, primarily, because isolation and cultivation of most archaea in the laboratory, and accordingly, experimental characterization of archaeal genes, are difficult. In the present study, we present quantitative characteristics of the archaeal genomic dark matter and discuss comparative genomic approaches for functional prediction for ‘hypothetical' proteins. We propose a list of top priority candidates for experimental characterization with a broad distribution among archaea and those that are characteristic of poorly studied major archaeal groups such as Thaumarchaea, DPANN (Diapherotrites, Parvarchaeota, Aenigmarchaeota, Nanoarchaeota and Nanohaloarchaeota) and Asgard.
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8
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Clouet-d'Orval B, Batista M, Bouvier M, Quentin Y, Fichant G, Marchfelder A, Maier LK. Insights into RNA-processing pathways and associated RNA-degrading enzymes in Archaea. FEMS Microbiol Rev 2018; 42:579-613. [PMID: 29684129 DOI: 10.1093/femsre/fuy016] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022] Open
Abstract
RNA-processing pathways are at the centre of regulation of gene expression. All RNA transcripts undergo multiple maturation steps in addition to covalent chemical modifications to become functional in the cell. This includes destroying unnecessary or defective cellular RNAs. In Archaea, information on mechanisms by which RNA species reach their mature forms and associated RNA-modifying enzymes are still fragmentary. To date, most archaeal actors and pathways have been proposed in light of information gathered from Bacteria and Eukarya. In this context, this review provides a state of the art overview of archaeal endoribonucleases and exoribonucleases that cleave and trim RNA species and also of the key small archaeal proteins that bind RNAs. Furthermore, synthetic up-to-date views of processing and biogenesis pathways of archaeal transfer and ribosomal RNAs as well as of maturation of stable small non-coding RNAs such as CRISPR RNAs, small C/D and H/ACA box guide RNAs, and other emerging classes of small RNAs are described. Finally, prospective post-transcriptional mechanisms to control archaeal messenger RNA quality and quantity are discussed.
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Affiliation(s)
- Béatrice Clouet-d'Orval
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Manon Batista
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Marie Bouvier
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Yves Quentin
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
| | - Gwennaele Fichant
- Laboratoire de Microbiologie et de Génétique Moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, 31062 Toulouse, France
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9
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Sandri M, Licastro D, Dal Monego S, Sgorlon S, Stefanon B. Investigation of rumen metagenome in Italian Simmental and Italian Holstein cows using a whole-genome shotgun sequencing technique. ITALIAN JOURNAL OF ANIMAL SCIENCE 2018. [DOI: 10.1080/1828051x.2018.1462110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Misa Sandri
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Università di Udine, Udine, Italy
| | | | | | - Sandy Sgorlon
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Università di Udine, Udine, Italy
| | - Bruno Stefanon
- Dipartimento di Scienze Agroalimentari, Ambientali e Animali, Università di Udine, Udine, Italy
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10
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Liu X, Shen X, Lai Y, Ji K, Sun H, Wang Y, Hou C, Zou N, Wan J, Yu J. Toxicological proteomic responses of halophyte Suaeda salsa to lead and zinc. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 134P1:163-171. [PMID: 27616546 DOI: 10.1016/j.ecoenv.2016.07.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 06/06/2023]
Abstract
The long term (30 days) toxicological effects of environmentally relevant concentrations of Pb2+ (20μg/L) and Zn2+ (100μg/L) were characterized in Suaeda salsa using proteomics techniques. The responsive proteins were related to metabolism (Krebs cycle and Calvin cycle), protein biosynthesis, stress and defense, energy, signaling pathway and photosynthesis in Pb2+, Zn2+ and Pb2++ Zn2+ exposed groups in S. salsa after exposures for 30 days. The proteomic profiles also showed differential responses in S. salsa to metal exposures. In Pb2+-treated group, the proteins were categorized into cystein metabolism and pentose phosphate pathway. The responsive proteins were basically involved in glutathione metabolism, glycolysis, cystein and methane metabolism, and voltage-dependent anion channel in Zn2+-treated group. In Pb2++ Zn2+-treated group, the proecular mechanism at protein level remtein responses were devided into tyrosine metabolism and glycolysis. Our results showed that the two typical heavy metals, lead and zinc, could induce toxicological effects in halophyte S. salsa at protein level.
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Affiliation(s)
- Xiaoli Liu
- School of Life Sciences, Ludong University, Yantai 264025, PR China.
| | - Xuejiao Shen
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Yongkai Lai
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Kang Ji
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Hushan Sun
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Yiyan Wang
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Chengzong Hou
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Ning Zou
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Junli Wan
- School of Life Sciences, Ludong University, Yantai 264025, PR China
| | - Junbao Yu
- The Coastal Resources and Environment Team for Blue-Yellow Area, Ludong University, Yantai 264025, PR China
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11
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Archaeal Clusters of Orthologous Genes (arCOGs): An Update and Application for Analysis of Shared Features between Thermococcales, Methanococcales, and Methanobacteriales. Life (Basel) 2015; 5:818-40. [PMID: 25764277 PMCID: PMC4390880 DOI: 10.3390/life5010818] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 02/25/2015] [Accepted: 02/28/2015] [Indexed: 11/18/2022] Open
Abstract
With the continuously accelerating genome sequencing from diverse groups of archaea and bacteria, accurate identification of gene orthology and availability of readily expandable clusters of orthologous genes are essential for the functional annotation of new genomes. We report an update of the collection of archaeal Clusters of Orthologous Genes (arCOGs) to cover, on average, 91% of the protein-coding genes in 168 archaeal genomes. The new arCOGs were constructed using refined algorithms for orthology identification combined with extensive manual curation, including incorporation of the results of several completed and ongoing research projects in archaeal genomics. A new level of classification is introduced, superclusters that unit two or more arCOGs and more completely reflect gene family evolution than individual, disconnected arCOGs. Assessment of the current archaeal genome annotation in public databases indicates that consistent use of arCOGs can significantly improve the annotation quality. In addition to their utility for genome annotation, arCOGs also are a platform for phylogenomic analysis. We explore this aspect of arCOGs by performing a phylogenomic study of the Thermococci that are traditionally viewed as the basal branch of the Euryarchaeota. The results of phylogenomic analysis that involved both comparison of multiple phylogenetic trees and a search for putative derived shared characters by using phyletic patterns extracted from the arCOGs reveal a likely evolutionary relationship between the Thermococci, Methanococci, and Methanobacteria. The arCOGs are expected to be instrumental for a comprehensive phylogenomic study of the archaea.
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12
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Abstract
MBF1 (multi-protein bridging factor 1) is a protein containing a conserved HTH (helix-turn-helix) domain in both eukaryotes and archaea. Eukaryotic MBF1 has been reported to function as a transcriptional co-activator that physically bridges transcription regulators with the core transcription initiation machinery of RNA polymerase II. In addition, MBF1 has been found to be associated with polyadenylated mRNA in yeast as well as in mammalian cells. aMBF1 (archaeal MBF1) is very well conserved among most archaeal lineages; however, its function has so far remained elusive. To address this, we have conducted a molecular characterization of this aMBF1. Affinity purification of interacting proteins indicates that aMBF1 binds to ribosomal subunits. On sucrose density gradients, aMBF1 co-fractionates with free 30S ribosomal subunits as well as with 70S ribosomes engaged in translation. Binding of aMBF1 to ribosomes does not inhibit translation. Using NMR spectroscopy, we show that aMBF1 contains a long intrinsically disordered linker connecting the predicted N-terminal zinc-ribbon domain with the C-terminal HTH domain. The HTH domain, which is conserved in all archaeal and eukaryotic MBF1 homologues, is directly involved in the association of aMBF1 with ribosomes. The disordered linker of the ribosome-bound aMBF1 provides the N-terminal domain with high flexibility in the aMBF1-ribosome complex. Overall, our findings suggest a role for aMBF1 in the archaeal translation process.
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13
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Feng Y, Song X, Lin J, Xuan J, Cui Q, Wang J. Structure determination of archaea-specific ribosomal protein L46a reveals a novel protein fold. Biochem Biophys Res Commun 2014; 450:67-72. [PMID: 24875358 DOI: 10.1016/j.bbrc.2014.05.077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 05/16/2014] [Indexed: 01/21/2023]
Abstract
Three archaea-specific ribosomal proteins recently identified show no sequence homology with other known proteins. Here we determined the structure of L46a, the most conserved one among the three proteins, from Sulfolobus solfataricus P2 using NMR spectroscopy. The structure presents a twisted β-sheet formed by the N-terminal part and two helices at the C-terminus. The L46a structure has a positively charged surface which is conserved in the L46a protein family and is the potential rRNA-binding site. Searching homologous structures in Protein Data Bank revealed that the structure of L46a represents a novel protein fold. The backbone dynamics identified by NMR relaxation experiments reveal significant flexibility at the rRNA binding surface. The potential position of L46a on the ribosome was proposed by fitting the structure into a previous electron microscopy map of the ribosomal 50S subunit, which indicated that L46a contacts to domain I of 23S rRNA near a multifunctional ribosomal protein L7ae.
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Affiliation(s)
- Yingang Feng
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China.
| | - Xiaxia Song
- Department of Biological Science and Engineering, School of Chemical and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jinzhong Lin
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Jinsong Xuan
- Department of Biological Science and Engineering, School of Chemical and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Qiu Cui
- Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Jinfeng Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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14
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Ghalei H, von Moeller H, Eppers D, Sohmen D, Wilson DN, Loll B, Wahl MC. Entrapment of DNA in an intersubunit tunnel system of a single-stranded DNA-binding protein. Nucleic Acids Res 2014; 42:6698-708. [PMID: 24744237 PMCID: PMC4041433 DOI: 10.1093/nar/gku259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Instead of a classical single-stranded deoxyribonuleic acid (DNA)-binding protein (SSB), some hyperthermophilic crenarchaea harbor a non-canonical SSB termed ThermoDBP. Two related but poorly characterized groups of proteins, which share the ThermoDBP N-terminal DNA-binding domain, have a broader phylogenetic distribution and co-exist with ThermoDBPs and/or other SSBs. We have investigated the nucleic acid binding properties and crystal structures of representatives of these groups of ThermoDBP-related proteins (ThermoDBP-RPs) 1 and 2. ThermoDBP-RP 1 and 2 oligomerize by different mechanisms and only ThermoDBP-RP2 exhibits strong single-stranded DNA affinity in vitro. A crystal structure of ThermoDBP-RP2 in complex with DNA reveals how the NTD common to ThermoDBPs and ThermoDBP-RPs can contact the nucleic acid in a manner that allows a symmetric homotetrameric protein complex to bind single-stranded DNA molecules asymmetrically. While single-stranded DNA wraps around the surface or binds along channels of previously investigated SSBs, it traverses an internal, intersubunit tunnel system of a ThermoDBP-RP2 tetramer. Our results indicate that some archaea have acquired special SSBs for genome maintenance in particularly challenging environments.
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Affiliation(s)
- Homa Ghalei
- Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie, AG Strukturbiochemie, Takustr. 6, 14195 Berlin, Germany Max-Planck-Institute for Biophysical Chemistry, Department of Cellular Biochemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Holger von Moeller
- Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie, AG Strukturbiochemie, Takustr. 6, 14195 Berlin, Germany
| | - Detlef Eppers
- Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie, AG Strukturbiochemie, Takustr. 6, 14195 Berlin, Germany
| | - Daniel Sohmen
- Gene Center, Department of Biochemistry and Center of integrated Protein Science Munich (CiPSM), University of Munich, Feodor-Lynenstr. 25, 81377 Munich, Germany
| | - Daniel N Wilson
- Gene Center, Department of Biochemistry and Center of integrated Protein Science Munich (CiPSM), University of Munich, Feodor-Lynenstr. 25, 81377 Munich, Germany
| | - Bernhard Loll
- Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie, AG Strukturbiochemie, Takustr. 6, 14195 Berlin, Germany
| | - Markus C Wahl
- Freie Universität Berlin, Fachbereich Biologie, Chemie, Pharmazie, Institut für Chemie und Biochemie, AG Strukturbiochemie, Takustr. 6, 14195 Berlin, Germany
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15
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Afanasyeva A, Hirtreiter A, Schreiber A, Grohmann D, Pobegalov G, McKay AR, Tsaneva I, Petukhov M, Käs E, Grigoriev M, Werner F. Lytic water dynamics reveal evolutionarily conserved mechanisms of ATP hydrolysis by TIP49 AAA+ ATPases. Structure 2014; 22:549-59. [PMID: 24613487 PMCID: PMC3991330 DOI: 10.1016/j.str.2014.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 01/29/2014] [Accepted: 02/01/2014] [Indexed: 11/24/2022]
Abstract
Eukaryotic TIP49a (Pontin) and TIP49b (Reptin) AAA+ ATPases play essential roles in key cellular processes. How their weak ATPase activity contributes to their important functions remains largely unknown and difficult to analyze because of the divergent properties of TIP49a and TIP49b proteins and of their homo- and hetero-oligomeric assemblies. To circumvent these complexities, we have analyzed the single ancient TIP49 ortholog found in the archaeon Methanopyrus kandleri (mkTIP49). All-atom homology modeling and molecular dynamics simulations validated by biochemical assays reveal highly conserved organizational principles and identify key residues for ATP hydrolysis. An unanticipated crosstalk between Walker B and Sensor I motifs impacts the dynamics of water molecules and highlights a critical role of trans-acting aspartates in the lytic water activation step that is essential for the associative mechanism of ATP hydrolysis. We have studied the single TIP49 ortholog (mkTIP49) from the archaeon M. kandleri We propose a model for assembly of the pre-transition state for ATP hydrolysis Trans-aspartates downregulate ATP hydrolysis by mkTIP49 hexamers Mutational analysis confirms a highly conserved mechanism for lytic water activation
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Affiliation(s)
- Arina Afanasyeva
- Department of Biophysics, Saint Petersburg State Polytechnical University, Saint Petersburg 195251, Russia; Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Gatchina 188300, Russia
| | - Angela Hirtreiter
- Division of Biosciences, Institute for Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Anne Schreiber
- Division of Biosciences, Institute for Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Dina Grohmann
- Physikalische und Theoretische Chemie - NanoBioSciences, Technische Universität Braunschweig, Braunschweig 38106, Germany
| | - Georgii Pobegalov
- Department of Biophysics, Saint Petersburg State Polytechnical University, Saint Petersburg 195251, Russia
| | - Adam R McKay
- Department of Chemistry, University College London, London WC1H 0AJ, UK
| | - Irina Tsaneva
- Division of Biosciences, Institute for Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Michael Petukhov
- Department of Biophysics, Saint Petersburg State Polytechnical University, Saint Petersburg 195251, Russia; Division of Molecular and Radiation Biophysics, Petersburg Nuclear Physics Institute, Gatchina 188300, Russia
| | - Emmanuel Käs
- UMR 5099, CNRS, Toulouse F-31000, France; Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse, Toulouse F-31000, France.
| | - Mikhail Grigoriev
- UMR 5099, CNRS, Toulouse F-31000, France; Laboratoire de Biologie Moléculaire Eucaryote, Université de Toulouse, Toulouse F-31000, France.
| | - Finn Werner
- Division of Biosciences, Institute for Structural and Molecular Biology, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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16
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Kolesnikova O, Back R, Graille M, Séraphin B. Identification of the Rps28 binding motif from yeast Edc3 involved in the autoregulatory feedback loop controlling RPS28B mRNA decay. Nucleic Acids Res 2013; 41:9514-23. [PMID: 23956223 PMCID: PMC3814365 DOI: 10.1093/nar/gkt607] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae, the Edc3 protein was previously reported to participate in the auto-regulatory feedback loop controlling the level of the RPS28B messenger RNA (mRNA). We show here that Edc3 binds directly and tightly to the globular core of Rps28 ribosomal protein. This binding occurs through a motif that is present exclusively in Edc3 proteins from yeast belonging to the Saccharomycetaceae phylum. Functional analyses indicate that the ability of Edc3 to interact with Rps28 is not required for its general function and for its role in the regulation of the YRA1 pre-mRNA decay. In contrast, this interaction appears to be exclusively required for the auto-regulatory mechanism controlling the RPS28B mRNA decay. These observations suggest a plausible model for the evolutionary appearance of a Rps28 binding motif in Edc3.
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Affiliation(s)
- Olga Kolesnikova
- Equipe Labellisée La Ligue, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Centre National de la Recherche Scientifique (CNRS) UMR 7104/Institut National de la Santé et de la Recherche Médicale (INSERM) U964/Université de Strasbourg, 67404 Illkirch, France, Ecole Polytechnique, Laboratoire de Biochimie, CNRS UMR7654, 91128 Palaiseau Cedex, France and Institut de Biochimie et Biophysique Moléculaire et Cellulaire (IBBMC), CNRS, UMR8619, Bat 430, Université Paris Sud, 91405 Orsay Cedex, France
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17
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Liu X, Wu H, Ji C, Wei L, Zhao J, Yu J. An integrated proteomic and metabolomic study on the chronic effects of mercury in Suaeda salsa under an environmentally relevant salinity. PLoS One 2013; 8:e64041. [PMID: 23696864 PMCID: PMC3655940 DOI: 10.1371/journal.pone.0064041] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 04/09/2013] [Indexed: 12/05/2022] Open
Abstract
As an environmental contaminant, mercury is of great concern due to its high risk to environmental and human health. The halophyte Suaeda salsa is the dominant plant in the intertidal zones of the Yellow River Delta (YRD) where has been contaminated by mercury in some places. This study aimed at evaluating the chronic effects of mercury (Hg2+, 20 µg L−1) and the influence of an environmentally relevant salinity (NaCl, 500 mM) on mercury-induced effects in S. salsa. A total of 43 protein spots with significant changes were identified in response to Hg2+, salinity and combined Hg2+ and salinity. These proteins can be categorized into diverse functional classes, related to metabolic processes, photosynthesis, stress response, protein fate, energy metabolism, signaling pathways and immunosuppression. Metabolic responses demonstrated that Hg2+ could disturb protein and energy metabolisms in S. salsa co-exposed with or without salinity. In addition, both antagonistic and synergistic effects between Hg2+ and salinity were confirmed by differential levels of proteins (magnesium-chelatase and ribulose-l,5-bisphosphate carboxylase/oxygenase) and metabolites (valine, malonate, asparagine, glycine, fructose and glucose) in S. salsa. These findings suggest that a combination of proteomics and metabolomics can provide insightful information of environmental contaminant-induced effects in plants at molecular levels.
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Affiliation(s)
- Xiaoli Liu
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai Shandong, P. R. China
- The Graduate School of Chinese Academy of Sciences, Beijing, P. R. China
| | - Huifeng Wu
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai Shandong, P. R. China
- * E-mail:
| | - Chenglong Ji
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai Shandong, P. R. China
- The Graduate School of Chinese Academy of Sciences, Beijing, P. R. China
| | - Lei Wei
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai Shandong, P. R. China
- The Graduate School of Chinese Academy of Sciences, Beijing, P. R. China
| | - Jianmin Zhao
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai Shandong, P. R. China
| | - Junbao Yu
- Key Laboratory of Coastal Zone Environmental Processes, Yantai Institute of Coastal Zone Research (YIC), Chinese Academy of Sciences (CAS); Shandong Provincial Key Laboratory of Coastal Zone Environmental Processes, YICCAS, Yantai Shandong, P. R. China
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18
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Structures of the human and Drosophila 80S ribosome. Nature 2013; 497:80-5. [DOI: 10.1038/nature12104] [Citation(s) in RCA: 410] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 03/19/2013] [Indexed: 12/19/2022]
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19
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Eichler J, Maupin-Furlow J. Post-translation modification in Archaea: lessons from Haloferax volcanii and other haloarchaea. FEMS Microbiol Rev 2012; 37:583-606. [PMID: 23167813 DOI: 10.1111/1574-6976.12012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 11/13/2012] [Accepted: 11/13/2012] [Indexed: 01/11/2023] Open
Abstract
As an ever-growing number of genome sequences appear, it is becoming increasingly clear that factors other than genome sequence impart complexity to the proteome. Of the various sources of proteomic variability, post-translational modifications (PTMs) most greatly serve to expand the variety of proteins found in the cell. Likewise, modulating the rates at which different proteins are degraded also results in a constantly changing cellular protein profile. While both strategies for generating proteomic diversity are adopted by organisms across evolution, the responsible pathways and enzymes in Archaea are often less well described than are their eukaryotic and bacterial counterparts. Studies on halophilic archaea, in particular Haloferax volcanii, originally isolated from the Dead Sea, are helping to fill the void. In this review, recent developments concerning PTMs and protein degradation in the haloarchaea are discussed.
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Affiliation(s)
- Jerry Eichler
- Department of Life Sciences, Ben Gurion University, Beersheva, Israel.
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20
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Armache JP, Anger AM, Márquez V, Franckenberg S, Fröhlich T, Villa E, Berninghausen O, Thomm M, Arnold GJ, Beckmann R, Wilson DN. Promiscuous behaviour of archaeal ribosomal proteins: implications for eukaryotic ribosome evolution. Nucleic Acids Res 2012; 41:1284-93. [PMID: 23222135 PMCID: PMC3553981 DOI: 10.1093/nar/gks1259] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In all living cells, protein synthesis occurs on ribonucleoprotein particles called ribosomes. Molecular models have been reported for complete bacterial 70S and eukaryotic 80S ribosomes; however, only molecular models of large 50S subunits have been reported for archaea. Here, we present a complete molecular model for the Pyrococcus furiosus 70S ribosome based on a 6.6 Å cryo-electron microscopy map. Moreover, we have determined cryo-electron microscopy reconstructions of the Euryarchaeota Methanococcus igneus and Thermococcus kodakaraensis 70S ribosomes and Crenarchaeota Staphylothermus marinus 50S subunit. Examination of these structures reveals a surprising promiscuous behavior of archaeal ribosomal proteins: We observe intersubunit promiscuity of S24e and L8e (L7ae), the latter binding to the head of the small subunit, analogous to S12e in eukaryotes. Moreover, L8e and L14e exhibit intrasubunit promiscuity, being present in two copies per archaeal 50S subunit, with the additional binding site of L14e analogous to the related eukaryotic r-protein L27e. Collectively, these findings suggest insights into the evolution of eukaryotic ribosomal proteins through increased copy number and binding site promiscuity.
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Affiliation(s)
- Jean-Paul Armache
- Gene Center and Department of Biochemistry, Ludwig-Maximilians-Universität München, Feodor-Lynen-Str. 25, 81377 Munich, Germany
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21
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Yutin N, Puigbò P, Koonin EV, Wolf YI. Phylogenomics of prokaryotic ribosomal proteins. PLoS One 2012; 7:e36972. [PMID: 22615861 PMCID: PMC3353972 DOI: 10.1371/journal.pone.0036972] [Citation(s) in RCA: 189] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 04/16/2012] [Indexed: 11/29/2022] Open
Abstract
Archaeal and bacterial ribosomes contain more than 50 proteins, including 34 that are universally conserved in the three domains of cellular life (bacteria, archaea, and eukaryotes). Despite the high sequence conservation, annotation of ribosomal (r-) protein genes is often difficult because of their short lengths and biased sequence composition. We developed an automated computational pipeline for identification of r-protein genes and applied it to 995 completely sequenced bacterial and 87 archaeal genomes available in the RefSeq database. The pipeline employs curated seed alignments of r-proteins to run position-specific scoring matrix (PSSM)-based BLAST searches against six-frame genome translations, mitigating possible gene annotation errors. As a result of this analysis, we performed a census of prokaryotic r-protein complements, enumerated missing and paralogous r-proteins, and analyzed the distributions of ribosomal protein genes among chromosomal partitions. Phyletic patterns of bacterial and archaeal r-protein genes were mapped to phylogenetic trees reconstructed from concatenated alignments of r-proteins to reveal the history of likely multiple independent gains and losses. These alignments, available for download, can be used as search profiles to improve genome annotation of r-proteins and for further comparative genomics studies.
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Affiliation(s)
- Natalya Yutin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Pere Puigbò
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Eugene V. Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yuri I. Wolf
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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22
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Maupin-Furlow JA, Humbard MA, Kirkland PA. Extreme challenges and advances in archaeal proteomics. Curr Opin Microbiol 2012; 15:351-6. [PMID: 22386447 DOI: 10.1016/j.mib.2012.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/06/2012] [Accepted: 02/10/2012] [Indexed: 12/14/2022]
Abstract
Archaea display amazing physiological properties that are of interest to understand at the molecular level including the ability to thrive at extreme environmental conditions, the presence of novel metabolic pathways (e.g. methanogenesis, methylaspartate cycle) and the use of eukaryotic-like protein machineries for basic cellular functions. Coupling traditional genetic and biochemical approaches with advanced technologies, such as genomics and proteomics, provides an avenue for scientists to discover new aspects related to the molecular physiology of archaea. This review emphasizes the unusual properties of archaeal proteomes and how high-throughput and specialized mass spectrometry-based proteomic studies have provided insight into the molecular properties of archaeal cells.
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Affiliation(s)
- Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611-0700, USA.
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23
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Pech M, Nierhaus KH. Identical binding sites--nonidentical functions in Eukarya and Archaea: the complex of aeIF6 with the large ribosomal subunit. J Mol Biol 2012; 418:131-3. [PMID: 22381407 DOI: 10.1016/j.jmb.2012.02.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Markus Pech
- Max-Planck-Institut für Molekulare Genetik, Abteilung Vingron, AG Ribosomen, Ihnestrasse 73, D-14195 Berlin, Germany
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24
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Cryo-EM structure of the archaeal 50S ribosomal subunit in complex with initiation factor 6 and implications for ribosome evolution. J Mol Biol 2012; 418:145-60. [PMID: 22306461 DOI: 10.1016/j.jmb.2012.01.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 01/05/2012] [Accepted: 01/13/2012] [Indexed: 11/20/2022]
Abstract
Translation of mRNA into proteins by the ribosome is universally conserved in all cellular life. The composition and complexity of the translation machinery differ markedly between the three domains of life. Organisms from the domain Archaea show an intermediate level of complexity, sharing several additional components of the translation machinery with eukaryotes that are absent in bacteria. One of these translation factors is initiation factor 6 (IF6), which associates with the large ribosomal subunit. We have reconstructed the 50S ribosomal subunit from the archaeon Methanothermobacter thermautotrophicus in complex with archaeal IF6 at 6.6 Å resolution using cryo-electron microscopy (EM). The structure provides detailed architectural insights into the 50S ribosomal subunit from a methanogenic archaeon through identification of the rRNA expansion segments and ribosomal proteins that are shared between this archaeal ribosome and eukaryotic ribosomes but are mostly absent in bacteria and in some archaeal lineages. Furthermore, the structure reveals that, in spite of highly divergent evolutionary trajectories of the ribosomal particle and the acquisition of novel functions of IF6 in eukaryotes, the molecular binding of IF6 on the ribosome is conserved between eukaryotes and archaea. The structure also provides a snapshot of the reductive evolution of the archaeal ribosome and offers new insights into the evolution of the translation system in archaea.
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