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Kirschning A. Why pyridoxal phosphate could be a functional predecessor of thiamine pyrophosphate and speculations on a primordial metabolism. RSC Chem Biol 2024; 5:508-517. [PMID: 38846080 PMCID: PMC11151856 DOI: 10.1039/d4cb00016a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/15/2024] [Indexed: 06/09/2024] Open
Abstract
The account attempts to substantiate the hypothesis that, from an evolutionary perspective, the coenzyme couple pyridoxal phosphate and pyridoxamine phosphate preceded the coenzyme thiamine pyrophosphate and acted as its less efficient chemical analogue in some form of early metabolism. The analysis combines mechanism-based chemical reactivity with biosynthetic arguments and provides evidence that vestiges of "TPP-like reactivity" are still found for PLP today. From these thoughts, conclusions can be drawn about the key elements of a primordial form of metabolism, which includes the citric acid cycle, amino acid biosynthesis and the pentose phosphate pathway.
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Affiliation(s)
- Andreas Kirschning
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B 30167 Hannover Germany
- Uppsala Biomedical Center (BMC), University Uppsala, Husargatan 3 752 37 Uppsala Sweden
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2
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Abstract
α-Amino acids are essential molecular constituents of life, twenty of which are privileged because they are encoded by the ribosomal machinery. The question remains open as to why this number and why this 20 in particular, an almost philosophical question that cannot be conclusively resolved. They are closely related to the evolution of the genetic code and whether nucleic acids, amino acids, and peptides appeared simultaneously and were available under prebiotic conditions when the first self-sufficient complex molecular system emerged on Earth. This report focuses on prebiotic and metabolic aspects of amino acids and proteins starting with meteorites, followed by their formation, including peptides, under plausible prebiotic conditions, and the major biosynthetic pathways in the various kingdoms of life. Coenzymes play a key role in the present analysis in that amino acid metabolism is linked to glycolysis and different variants of the tricarboxylic acid cycle (TCA, rTCA, and the incomplete horseshoe version) as well as the biosynthesis of the most important coenzymes. Thus, the report opens additional perspectives and facets on the molecular evolution of primary metabolism.
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Affiliation(s)
- Andreas Kirschning
- Institute of Organic ChemistryLeibniz University HannoverSchneiderberg 1B30167HannoverGermany
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Abstract
The evolution of coenzymes, or their impact on the origin of life, is fundamental for understanding our own existence. Having established reasonable hypotheses about the emergence of prebiotic chemical building blocks, which were probably created under palaeogeochemical conditions, and surmising that these smaller compounds must have become integrated to afford complex macromolecules such as RNA, the question of coenzyme origin and its relation to the evolution of functional biochemistry should gain new impetus. Many coenzymes have a simple chemical structure and are often nucleotide-derived, which suggests that they may have coexisted with the emergence of RNA and may have played a pivotal role in early metabolism. Based on current theories of prebiotic evolution, which attempt to explain the emergence of privileged organic building blocks, this Review discusses plausible hypotheses on the prebiotic formation of key elements within selected extant coenzymes. In combination with prebiotic RNA, coenzymes may have dramatically broadened early protometabolic networks and the catalytic scope of RNA during the evolution of life.
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Affiliation(s)
- Andreas Kirschning
- Institut für Organische Chemie und Biomolekulares Wirkstoffzentrum (BMWZ)Leibniz Universität HannoverSchneiderberg 1B30167HannoverGermany
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4
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Affiliation(s)
- Andreas Kirschning
- Institut für Organische Chemie und Biomolekulares Wirkstoffzentrum (BMWZ) Leibniz Universität Hannover Schneiderberg 1B 30167 Hannover Deutschland
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Martin WF. Older Than Genes: The Acetyl CoA Pathway and Origins. Front Microbiol 2020; 11:817. [PMID: 32655499 PMCID: PMC7325901 DOI: 10.3389/fmicb.2020.00817] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/06/2020] [Indexed: 11/13/2022] Open
Abstract
For decades, microbiologists have viewed the acetyl CoA pathway and organisms that use it for H2-dependent carbon and energy metabolism, acetogens and methanogens, as ancient. Classical evidence and newer evidence indicating the antiquity of the acetyl CoA pathway are summarized here. The acetyl CoA pathway requires approximately 10 enzymes, roughly as many organic cofactors, and more than 500 kDa of combined subunit molecular mass to catalyze the conversion of H2 and CO2 to formate, acetate, and pyruvate in acetogens and methanogens. However, a single hydrothermal vent alloy, awaruite (Ni3Fe), can convert H2 and CO2 to formate, acetate, and pyruvate under mild hydrothermal conditions on its own. The chemical reactions of H2 and CO2 to pyruvate thus have a natural tendency to occur without enzymes, given suitable inorganic catalysts. This suggests that the evolution of the enzymatic acetyl CoA pathway was preceded by-and patterned along-a route of naturally occurring exergonic reactions catalyzed by transition metal minerals that could activate H2 and CO2 by chemisorption. The principle of forward (autotrophic) pathway evolution from preexisting non-enzymatic reactions is generalized to the concept of patterned evolution of pathways. In acetogens, exergonic reduction of CO2 by H2 generates acyl phosphates by highly reactive carbonyl groups undergoing attack by inert inorganic phosphate. In that ancient reaction of biochemical energy conservation, the energy behind formation of the acyl phosphate bond resides in the carbonyl, not in phosphate. The antiquity of the acetyl CoA pathway is usually seen in light of CO2 fixation; its role in primordial energy coupling via acyl phosphates and substrate-level phosphorylation is emphasized here.
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Affiliation(s)
- William F. Martin
- Institute for Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
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6
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Bechard ME, Farahani P, Greene D, Pham A, Orry A, Rasche ME. Purification, kinetic characterization, and site-directed mutagenesis of Methanothermobacter thermautotrophicus RFAP Synthase Produced in Escherichia coli. AIMS Microbiol 2019; 5:186-204. [PMID: 31663056 PMCID: PMC6787355 DOI: 10.3934/microbiol.2019.3.186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/15/2019] [Indexed: 11/18/2022] Open
Abstract
Methane-producing archaea are among a select group of microorganisms that utilize tetrahydromethanopterin (H4MPT) as a one-carbon carrier instead of tetrahydrofolate. In H4MPT biosynthesis, β-ribofuranosylaminobenzene 5'-phosphate (RFAP) synthase catalyzes the production of RFAP, CO2, and pyrophosphate from p-aminobenzoic acid (pABA) and phosphoribosyl-pyrophosphate (PRPP). In this work, to gain insight into amino acid residues required for substrate binding, RFAP synthase from Methanothermobacter thermautotrophicus was produced in Escherichia coli, and site-directed mutagenesis was used to alter arginine 26 (R26) and aspartic acid 19 (D19), located in a conserved sequence of amino acids resembling the pABA binding site of dihydropteroate synthase. Replacement of R26 with lysine increased the KM for pABA by an order of magnitude relative to wild-type enzyme without substantially altering the KM for PRPP. Although replacement of D19 with alanine produced inactive enzyme, asparagine substitution allowed retention of some activity, and the K M for pABA increased about threefold relative to wild-type enzyme. A molecular model developed by threading RFAP synthase onto the crystal structure of homoserine kinase places R26 in the proposed active site. In the static model, D19 is located close to the active site, yet appears too far away to influence ligand binding directly. This may be indicative of the protein conformational change predicted previously in the Bi-Ter kinetic mechanism and/or formation of the active site at the interface of two subunits. Due to the vital role of RFAP synthase in H4MPT biosynthesis, insights into the mode of substrate binding and mechanism could be beneficial for developing RFAP synthase inhibitors designed to reduce the production of methane as a greenhouse gas.
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Affiliation(s)
- Matthew E Bechard
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
| | - Payam Farahani
- Chemistry and Biochemistry Department, California State University at Fullerton, 800 North State College Blvd., Fullerton, CA 92834
| | - Dina Greene
- Northern California Regional Laboratories, The Permanente Medical Group, Berkeley, CA 94710
| | - Anna Pham
- Chemistry and Biochemistry Department, California State University at Fullerton, 800 North State College Blvd., Fullerton, CA 92834
| | - Andrew Orry
- Molsoft L.L.C., 11199 Sorrento Valley Road, S209, San Diego, CA 92121
| | - Madeline E Rasche
- Chemistry and Biochemistry Department, California State University at Fullerton, 800 North State College Blvd., Fullerton, CA 92834
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Phosphoribosyl Diphosphate (PRPP): Biosynthesis, Enzymology, Utilization, and Metabolic Significance. Microbiol Mol Biol Rev 2016; 81:81/1/e00040-16. [PMID: 28031352 DOI: 10.1128/mmbr.00040-16] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Phosphoribosyl diphosphate (PRPP) is an important intermediate in cellular metabolism. PRPP is synthesized by PRPP synthase, as follows: ribose 5-phosphate + ATP → PRPP + AMP. PRPP is ubiquitously found in living organisms and is used in substitution reactions with the formation of glycosidic bonds. PRPP is utilized in the biosynthesis of purine and pyrimidine nucleotides, the amino acids histidine and tryptophan, the cofactors NAD and tetrahydromethanopterin, arabinosyl monophosphodecaprenol, and certain aminoglycoside antibiotics. The participation of PRPP in each of these metabolic pathways is reviewed. Central to the metabolism of PRPP is PRPP synthase, which has been studied from all kingdoms of life by classical mechanistic procedures. The results of these analyses are unified with recent progress in molecular enzymology and the elucidation of the three-dimensional structures of PRPP synthases from eubacteria, archaea, and humans. The structures and mechanisms of catalysis of the five diphosphoryltransferases are compared, as are those of selected enzymes of diphosphoryl transfer, phosphoryl transfer, and nucleotidyl transfer reactions. PRPP is used as a substrate by a large number phosphoribosyltransferases. The protein structures and reaction mechanisms of these phosphoribosyltransferases vary and demonstrate the versatility of PRPP as an intermediate in cellular physiology. PRPP synthases appear to have originated from a phosphoribosyltransferase during evolution, as demonstrated by phylogenetic analysis. PRPP, furthermore, is an effector molecule of purine and pyrimidine nucleotide biosynthesis, either by binding to PurR or PyrR regulatory proteins or as an allosteric activator of carbamoylphosphate synthetase. Genetic analyses have disclosed a number of mutants altered in the PRPP synthase-specifying genes in humans as well as bacterial species.
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Poole LB. The basics of thiols and cysteines in redox biology and chemistry. Free Radic Biol Med 2015; 80:148-57. [PMID: 25433365 PMCID: PMC4355186 DOI: 10.1016/j.freeradbiomed.2014.11.013] [Citation(s) in RCA: 587] [Impact Index Per Article: 65.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/20/2014] [Accepted: 11/17/2014] [Indexed: 02/06/2023]
Abstract
Cysteine is one of the least abundant amino acids, yet it is frequently found as a highly conserved residue within functional (regulatory, catalytic, or binding) sites in proteins. It is the unique chemistry of the thiol or thiolate group of cysteine that imparts to functional sites their specialized properties (e.g., nucleophilicity, high-affinity metal binding, and/or ability to form disulfide bonds). Highlighted in this review are some of the basic biophysical and biochemical properties of cysteine groups and the equations that apply to them, particularly with respect to pKa and redox potential. Also summarized are the types of low-molecular-weight thiols present in high concentrations in most cells, as well as the ways in which modifications of cysteinyl residues can impart or regulate molecular functions important to cellular processes, including signal transduction.
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Affiliation(s)
- Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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Bobik TA, Morales EJ, Shin A, Cascio D, Sawaya MR, Arbing M, Yeates TO, Rasche ME. Structure of the methanofuran/methanopterin-biosynthetic enzyme MJ1099 from Methanocaldococcus jannaschii. Acta Crystallogr F Struct Biol Commun 2014; 70:1472-9. [PMID: 25372812 PMCID: PMC4231847 DOI: 10.1107/s2053230x1402130x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 09/25/2014] [Indexed: 11/10/2022] Open
Abstract
Prior studies have indicated that MJ1099 from Methanocaldococcus jannaschii has roles in the biosynthesis of tetrahydromethanopterin and methanofuran, two key cofactors of one-carbon (C1) metabolism in diverse organisms including the methanogenic archaea. Here, the structure of MJ1099 has been solved to 1.7 Å resolution using anomalous scattering methods. The results indicate that MJ1099 is a member of the TIM-barrel superfamily and that it is a homohexamer. Bioinformatic analyses identified a potential active site that is highly conserved among MJ1099 homologs and the key amino acids involved were identified. The results presented here should guide further studies of MJ1099 including mechanistic studies and possibly the development of inhibitors that target the methanogenic archaea in the digestive tracts of humans and that are a source of the greenhouse gas methane.
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Affiliation(s)
- Thomas A. Bobik
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Erick J. Morales
- Department of Chemistry and Biochemistry, California State University, Fullerton, CA 92834, USA
| | - Annie Shin
- Department of Energy Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Duilio Cascio
- Department of Energy Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Michael R. Sawaya
- Department of Energy Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Mark Arbing
- Department of Energy Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Todd O. Yeates
- Department of Energy Institute for Genomics and Proteomics, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Madeline E. Rasche
- Department of Chemistry and Biochemistry, California State University, Fullerton, CA 92834, USA
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Characterization of the frhAGB-encoding hydrogenase from a non-methanogenic hyperthermophilic archaeon. Extremophiles 2014; 19:109-18. [PMID: 25142159 DOI: 10.1007/s00792-014-0689-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/31/2014] [Indexed: 10/24/2022]
Abstract
The F420-reducing hydrogenase has been known as a key enzyme in methanogenesis. Its homologs have been identified in non-methanogenic hyperthermophilic archaea, including Thermococcus onnurineus NA1, but neither physiological function nor biochemical properties have been reported to date. The enzyme of T. onnurineus NA1 was distinguished from those of other methanogens and the members of the family Desulfurobacteriaceae with respect to the phylogenetic distribution of the α and β subunits, organization of frhAGB genes and conservation of F420-coordinating residues. RT-qPCR and Western blot analyses revealed frhA gene is not silent but is expressed in T. onnurineus NA1 grown in the presence of sulfur, carbon monoxide, or formate. The trimeric enzyme complex was purified to homogeneity via affinity chromatography from T. onnurineus NA1 and exhibited catalytic activity toward the electron acceptors such as viologens and flavins but not the deazaflavin coenzyme F420. This is the first biochemical study on the function of the frhAGB-encoding enzyme from a non-methanogenic archaea.
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McNamara DE, Cascio D, Jorda J, Bustos C, Wang TC, Rasche ME, Yeates TO, Bobik TA. Structure of dihydromethanopterin reductase, a cubic protein cage for redox transfer. J Biol Chem 2014; 289:8852-64. [PMID: 24523405 DOI: 10.1074/jbc.m113.522342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dihydromethanopterin reductase (Dmr) is a redox enzyme that plays a key role in generating tetrahydromethanopterin (H4MPT) for use in one-carbon metabolism by archaea and some bacteria. DmrB is a bacterial enzyme understood to reduce dihydromethanopterin (H2MPT) to H4MPT using flavins as the source of reducing equivalents, but the mechanistic details have not been elucidated previously. Here we report the crystal structure of DmrB from Burkholderia xenovorans at a resolution of 1.9 Å. Unexpectedly, the biological unit is a 24-mer composed of eight homotrimers located at the corners of a cubic cage-like structure. Within a homotrimer, each monomer-monomer interface exhibits an active site with two adjacently bound flavin mononucleotide (FMN) ligands, one deeply buried and tightly bound and one more peripheral, for a total of 48 ligands in the biological unit. Computational docking suggested that the peripheral site could bind either the observed FMN (the electron donor for the overall reaction) or the pterin, H2MPT (the electron acceptor for the overall reaction), in configurations ideal for electron transfer to and from the tightly bound FMN. On this basis, we propose that DmrB uses a ping-pong mechanism to transfer reducing equivalents from FMN to the pterin substrate. Sequence comparisons suggested that the catalytic mechanism is conserved among the bacterial homologs of DmrB and partially conserved in archaeal homologs, where an alternate electron donor is likely used. In addition to the mechanistic revelations, the structure of DmrB could help guide the development of anti-obesity drugs based on modification of the ecology of the human gut.
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Sousa FL, Martin WF. Biochemical fossils of the ancient transition from geoenergetics to bioenergetics in prokaryotic one carbon compound metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:964-81. [PMID: 24513196 DOI: 10.1016/j.bbabio.2014.02.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/27/2022]
Abstract
The deep dichotomy of archaea and bacteria is evident in many basic traits including ribosomal protein composition, membrane lipid synthesis, cell wall constituents, and flagellar composition. Here we explore that deep dichotomy further by examining the distribution of genes for the synthesis of the central carriers of one carbon units, tetrahydrofolate (H4F) and tetrahydromethanopterin (H4MPT), in bacteria and archaea. The enzymes underlying those distinct biosynthetic routes are broadly unrelated across the bacterial-archaeal divide, indicating that the corresponding pathways arose independently. That deep divergence in one carbon metabolism is mirrored in the structurally unrelated enzymes and different organic cofactors that methanogens (archaea) and acetogens (bacteria) use to perform methyl synthesis in their H4F- and H4MPT-dependent versions, respectively, of the acetyl-CoA pathway. By contrast, acetyl synthesis in the acetyl-CoA pathway - from a methyl group, CO2 and reduced ferredoxin - is simpler, uniform and conserved across acetogens and methanogens, and involves only transition metals as catalysts. The data suggest that the acetyl-CoA pathway, while being the most ancient of known CO2 assimilation pathways, reflects two phases in early evolution: an ancient phase in a geochemically confined and non-free-living universal common ancestor, in which acetyl thioester synthesis proceeded spontaneously with the help of geochemically supplied methyl groups, and a later phase that reflects the primordial divergence of the bacterial and archaeal stem groups, which independently invented genetically-encoded means to synthesize methyl groups via enzymatic reactions. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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Affiliation(s)
- Filipa L Sousa
- Institute for Molecular Evolution,University of Düsseldorf, 40225 Düsseldorf, Germany
| | - William F Martin
- Institute for Molecular Evolution,University of Düsseldorf, 40225 Düsseldorf, Germany.
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Pedrolli DB, Jankowitsch F, Schwarz J, Langer S, Nakanishi S, Mack M. Natural riboflavin analogs. Methods Mol Biol 2014; 1146:41-63. [PMID: 24764087 DOI: 10.1007/978-1-4939-0452-5_3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Riboflavin analogs have a good potential to serve as basic structures for the development of novel anti-infectives. Riboflavin analogs have multiple cellular targets, since riboflavin (as a precursor to flavin cofactors) is active at more than one site in the cell. As a result, the frequency of developing resistance to antimicrobials based on riboflavin analogs is expected to be significantly lower. The only known natural riboflavin analog with antibiotic function is roseoflavin from the bacterium Streptomyces davawensis. This antibiotic negatively affects flavoenzymes and FMN riboswitches. Another roseoflavin producer, Streptomyces cinnabarinus, was recently identified. Possibly, flavin analogs with antibiotic activity are more widespread than anticipated. The same could be true for flavin analogs yet to be discovered, which could constitute tools for cellular chemistry, thus allowing a further extension of the catalytic spectrum of flavoenzymes.
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Affiliation(s)
- Danielle Biscaro Pedrolli
- Institute for Technical Microbiology, Mannheim University of Applied Sciences, Paul-Wittsack-Str. 10, 68163, Mannheim, Germany
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Abstract
Studies on sulfur metabolism in archaea have revealed many novel enzymes and pathways and have advanced our understanding on metabolic processes, not only of the archaea, but of biology in general. A variety of dissimilatory sulfur metabolisms, i.e. reactions used for energy conservation, are found in archaea from both the Crenarchaeota and Euryarchaeota phyla. Although not yet fully characterized, major processes include aerobic elemental sulfur (S(0)) oxidation, anaerobic S(0) reduction, anaerobic sulfate/sulfite reduction and anaerobic respiration of organic sulfur. Assimilatory sulfur metabolism, i.e. reactions used for biosynthesis of sulfur-containing compounds, also possesses some novel features. Cysteine biosynthesis in some archaea uses a unique tRNA-dependent pathway. Fe-S cluster biogenesis in many archaea differs from that in bacteria and eukaryotes and requires unidentified components. The eukaryotic ubiquitin system is conserved in archaea and involved in both protein degradation and biosynthesis of sulfur-containing cofactors. Lastly, specific pathways are utilized for the biosynthesis of coenzyme M and coenzyme B, the sulfur-containing cofactors required for methanogenesis.
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Affiliation(s)
- Yuchen Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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15
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Siddaramappa S, Challacombe JF, DeCastro RE, Pfeiffer F, Sastre DE, Giménez MI, Paggi RA, Detter JC, Davenport KW, Goodwin LA, Kyrpides N, Tapia R, Pitluck S, Lucas S, Woyke T, Maupin-Furlow JA. A comparative genomics perspective on the genetic content of the alkaliphilic haloarchaeon Natrialba magadii ATCC 43099T. BMC Genomics 2012; 13:165. [PMID: 22559199 PMCID: PMC3403918 DOI: 10.1186/1471-2164-13-165] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 05/04/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Natrialba magadii is an aerobic chemoorganotrophic member of the Euryarchaeota and is a dual extremophile requiring alkaline conditions and hypersalinity for optimal growth. The genome sequence of Nab. magadii type strain ATCC 43099 was deciphered to obtain a comprehensive insight into the genetic content of this haloarchaeon and to understand the basis of some of the cellular functions necessary for its survival. RESULTS The genome of Nab. magadii consists of four replicons with a total sequence of 4,443,643 bp and encodes 4,212 putative proteins, some of which contain peptide repeats of various lengths. Comparative genome analyses facilitated the identification of genes encoding putative proteins involved in adaptation to hypersalinity, stress response, glycosylation, and polysaccharide biosynthesis. A proton-driven ATP synthase and a variety of putative cytochromes and other proteins supporting aerobic respiration and electron transfer were encoded by one or more of Nab. magadii replicons. The genome encodes a number of putative proteases/peptidases as well as protein secretion functions. Genes encoding putative transcriptional regulators, basal transcription factors, signal perception/transduction proteins, and chemotaxis/phototaxis proteins were abundant in the genome. Pathways for the biosynthesis of thiamine, riboflavin, heme, cobalamin, coenzyme F420 and other essential co-factors were deduced by in depth sequence analyses. However, approximately 36% of Nab. magadii protein coding genes could not be assigned a function based on Blast analysis and have been annotated as encoding hypothetical or conserved hypothetical proteins. Furthermore, despite extensive comparative genomic analyses, genes necessary for survival in alkaline conditions could not be identified in Nab. magadii. CONCLUSIONS Based on genomic analyses, Nab. magadii is predicted to be metabolically versatile and it could use different carbon and energy sources to sustain growth. Nab. magadii has the genetic potential to adapt to its milieu by intracellular accumulation of inorganic cations and/or neutral organic compounds. The identification of Nab. magadii genes involved in coenzyme biosynthesis is a necessary step toward further reconstruction of the metabolic pathways in halophilic archaea and other extremophiles. The knowledge gained from the genome sequence of this haloalkaliphilic archaeon is highly valuable in advancing the applications of extremophiles and their enzymes.
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Affiliation(s)
| | - Jean F Challacombe
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Rosana E DeCastro
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - Friedhelm Pfeiffer
- Department of Membrane Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Diego E Sastre
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - María I Giménez
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - Roberto A Paggi
- Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3250 4to Nivel, Mar del Plata, 7600, Argentina
| | - John C Detter
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Karen W Davenport
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Lynne A Goodwin
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Nikos Kyrpides
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Roxanne Tapia
- DOE Joint Genome Institute, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - Samuel Pitluck
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Susan Lucas
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Tanja Woyke
- DOE Joint Genome Institute, Walnut Creek, CA, 94598, USA
| | - Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Bldg. 981, Museum Rd., P.O. Box 110700, Gainesville, FL, 32611-0700, USA
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16
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Fournier GP, Andam CP, Alm EJ, Gogarten JP. Molecular evolution of aminoacyl tRNA synthetase proteins in the early history of life. ORIGINS LIFE EVOL B 2011; 41:621-32. [PMID: 22200905 DOI: 10.1007/s11084-011-9261-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 12/06/2011] [Indexed: 01/02/2023]
Abstract
Aminoacyl-tRNA synthetases (aaRS) consist of several families of functionally conserved proteins essential for translation and protein synthesis. Like nearly all components of the translation machinery, most aaRS families are universally distributed across cellular life, being inherited from the time of the Last Universal Common Ancestor (LUCA). However, unlike the rest of the translation machinery, aaRS have undergone numerous ancient horizontal gene transfers, with several independent events detected between domains, and some possibly involving lineages diverging before the time of LUCA. These transfers reveal the complexity of molecular evolution at this early time, and the chimeric nature of genomes within cells that gave rise to the major domains. Additionally, given the role of these protein families in defining the amino acids used for protein synthesis, sequence reconstruction of their pre-LUCA ancestors can reveal the evolutionary processes at work in the origin of the genetic code. In particular, sequence reconstructions of the paralog ancestors of isoleucyl- and valyl- RS provide strong empirical evidence that at least for this divergence, the genetic code did not co-evolve with the aaRSs; rather, both amino acids were already part of the genetic code before their cognate aaRSs diverged from their common ancestor. The implications of this observation for the early evolution of RNA-directed protein biosynthesis are discussed.
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Affiliation(s)
- Gregory P Fournier
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Abbas CA, Sibirny AA. Genetic control of biosynthesis and transport of riboflavin and flavin nucleotides and construction of robust biotechnological producers. Microbiol Mol Biol Rev 2011; 75:321-60. [PMID: 21646432 PMCID: PMC3122625 DOI: 10.1128/mmbr.00030-10] [Citation(s) in RCA: 239] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Riboflavin [7,8-dimethyl-10-(1'-d-ribityl)isoalloxazine, vitamin B₂] is an obligatory component of human and animal diets, as it serves as the precursor of flavin coenzymes, flavin mononucleotide, and flavin adenine dinucleotide, which are involved in oxidative metabolism and other processes. Commercially produced riboflavin is used in agriculture, medicine, and the food industry. Riboflavin synthesis starts from GTP and ribulose-5-phosphate and proceeds through pyrimidine and pteridine intermediates. Flavin nucleotides are synthesized in two consecutive reactions from riboflavin. Some microorganisms and all animal cells are capable of riboflavin uptake, whereas many microorganisms have distinct systems for riboflavin excretion to the medium. Regulation of riboflavin synthesis in bacteria occurs by repression at the transcriptional level by flavin mononucleotide, which binds to nascent noncoding mRNA and blocks further transcription (named the riboswitch). In flavinogenic molds, riboflavin overproduction starts at the stationary phase and is accompanied by derepression of enzymes involved in riboflavin synthesis, sporulation, and mycelial lysis. In flavinogenic yeasts, transcriptional repression of riboflavin synthesis is exerted by iron ions and not by flavins. The putative transcription factor encoded by SEF1 is somehow involved in this regulation. Most commercial riboflavin is currently produced or was produced earlier by microbial synthesis using special selected strains of Bacillus subtilis, Ashbya gossypii, and Candida famata. Whereas earlier RF overproducers were isolated by classical selection, current producers of riboflavin and flavin nucleotides have been developed using modern approaches of metabolic engineering that involve overexpression of structural and regulatory genes of the RF biosynthetic pathway as well as genes involved in the overproduction of the purine precursor of riboflavin, GTP.
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Affiliation(s)
| | - Andriy A. Sibirny
- Institute of Cell Biology, NAS of Ukraine, Lviv 79005, Ukraine
- University of Rzeszow, Rzeszow 35-601, Poland
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Abstract
Coenzyme M (2-mercaptoethanesulfonate; CoM) is one of several atypical cofactors discovered in methanogenic archaea which participate in the biological reduction of CO(2) to methane. Elegantly simple, CoM, so named for its role as a methyl carrier in all methanogenic archaea, is the smallest known organic cofactor. It was thought that this cofactor was used exclusively in methanogenesis until it was recently discovered that CoM is a key cofactor in the pathway of propylene metabolism in the gram-negative soil microorganism Xanthobacter autotrophicus Py2. A four-step pathway requiring CoM converts propylene and CO(2) to acetoacetate, which feeds into central metabolism. In this process, CoM is used to activate and convert highly electrophilic epoxypropane, formed from propylene epoxidation, into a nucleophilic species that undergoes carboxylation. The unique properties of CoM provide a chemical handle for orienting compounds for site-specific redox chemistry and stereospecific catalysis. The three-dimensional structures of several of the enzymes in the pathway of propylene metabolism in defined states have been determined, providing significant insights into both the enzyme mechanisms and the role of CoM in this pathway. These studies provide the structural basis for understanding the efficacy of CoM as a handle to direct organic substrate transformations at the active sites of enzymes.
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Nocek B, Evdokimova E, Proudfoot M, Kudritska M, Grochowski LL, White RH, Savchenko A, Yakunin AF, Edwards A, Joachimiak A. Structure of an amide bond forming F(420):gamma-glutamyl ligase from Archaeoglobus fulgidus -- a member of a new family of non-ribosomal peptide synthases. J Mol Biol 2007; 372:456-69. [PMID: 17669425 PMCID: PMC2678844 DOI: 10.1016/j.jmb.2007.06.063] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2007] [Revised: 06/18/2007] [Accepted: 06/21/2007] [Indexed: 10/23/2022]
Abstract
F(420) is a flavin-like redox-active coenzyme commonly used by archaea and some eubacteria in a variety of biochemical reactions in methanogenesis, the formation of secondary metabolites, the degradation of nitroaromatic compounds, activation of nitroimidazofurans, and F(420)-dependent photolysis in DNA repair. Coenzyme F(420)-2 biosynthesis from 7,8-didemethyl-8-hydroxy-5-deazariboflavin (Fo) and lactaldehyde involves six enzymatic steps and five proteins (CofA, CofB, CofC, CofD, and CofE). CofE, a F(420)-0:gamma-glutamyl ligase, is responsible for the last two enzymatic steps; it catalyses the GTP-dependent addition of two L-glutamate residues to F(420)-0 to form F(420)-2. CofE is found in archaea, the aerobic actinomycetes, and cyanobacteria. Here, we report the first crystal structure of the apo-F(420)-0:gamma-glutamyl ligase (CofE-AF) from Archaeoglobus fulgidus and its complex with GDP at 2.5 A and 1.35 A resolution, respectively. The structure of CofE-AF reveals a novel protein fold with an intertwined, butterfly-like dimer formed by two-domain monomers. GDP and Mn(2+) are bound within the putative active site in a large groove at the dimer interface. We show that the enzyme adds a glutamate residue to both F(420)-0 and F(420)-1 in two distinct steps. CofE represents the first member of a new structural family of non-ribosomal peptide synthases.
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Affiliation(s)
- B. Nocek
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
| | - E. Evdokimova
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - M. Proudfoot
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - M. Kudritska
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - L. L. Grochowski
- Department of Biochemistry, Virginia Polytechnic, Institute and State, University, Blacksburg, VA 24061-0308, USA
| | - R. H. White
- Department of Biochemistry, Virginia Polytechnic, Institute and State, University, Blacksburg, VA 24061-0308, USA
| | - A. Savchenko
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - A. F. Yakunin
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - A. Edwards
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Ontario, Canada M5G 1L6
| | - A. Joachimiak
- Midwest Center for Structural, Genomics and Structural, Biology Center, Biosciences, Argonne National Laboratory, 9700 South Cass Avenue, Building 202, Argonne, IL 60439, USA
- The University of Chicago, Department of Biochemistry and Molecular Biology, University of Chicago, 920 E. 58th St., Chicago, IL 60637, USA
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Testani JM, Dabelic R, Rasche ME. Chemical reduction of pterins to dihydropterins as substrates for enzymatic reactions. Anal Biochem 2006; 358:20-4. [PMID: 16962549 DOI: 10.1016/j.ab.2006.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2006] [Revised: 07/18/2006] [Accepted: 08/01/2006] [Indexed: 11/22/2022]
Abstract
Dihydropterins are important intermediates in various metabolic pathways, including the biosynthesis of tetrahydrofolate and tetrahydromethanopterin, a key coenzyme in the one-carbon metabolism of methanogenic Archaea. Some procedures for the reduction of pterins to dihydropterins may produce undesirable tetrahydropterin contaminants. This work describes a procedure for the rapid reduction of pterins to dihydropterins while minimizing tetrahydropterin production that may be particularly useful in producing substrates for enzyme reactions when the dihydropterin substrate cannot be purchased commercially.
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Affiliation(s)
- Jeffrey M Testani
- University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Belen’kii L, Gramenitskaya V, Evdokimenkova Y. The Literature of Heterocyclic Chemistry, Part IX, 2002–2004. ADVANCES IN HETEROCYCLIC CHEMISTRY 2006. [DOI: 10.1016/s0065-2725(06)92004-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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22
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Chistoserdova L, Rasche ME, Lidstrom ME. Novel dephosphotetrahydromethanopterin biosynthesis genes discovered via mutagenesis in Methylobacterium extorquens AM1. J Bacteriol 2005; 187:2508-12. [PMID: 15774894 PMCID: PMC1065231 DOI: 10.1128/jb.187.7.2508-2512.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2004] [Accepted: 12/14/2004] [Indexed: 11/20/2022] Open
Abstract
Methylobacterium extorquens AM1 was used to explore the genetics of dephosphotetrahydromethanopterin (dH(4)MPT) biosynthesis. Strains with mutations in eight "archaeal-type" genes linked on the chromosome of M. extorquens AM1 were analyzed for the ability to synthesize dH(4)MPT, and six were found to be dH(4)MPT negative. Putative functions of these genes in dH(4)MPT biosynthesis are discussed.
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Affiliation(s)
- Ludmila Chistoserdova
- 231 Wilcox Hall, Box 352125, Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
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23
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Buchenau B, Thauer RK. Tetrahydrofolate-specific enzymes in Methanosarcina barkeri and growth dependence of this methanogenic archaeon on folic acid or p-aminobenzoic acid. Arch Microbiol 2004; 182:313-25. [PMID: 15349715 DOI: 10.1007/s00203-004-0714-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Revised: 07/15/2004] [Accepted: 07/15/2004] [Indexed: 10/26/2022]
Abstract
Methanogenic archaea are generally thought to use tetrahydromethanopterin or tetrahydrosarcinapterin (H4SPT) rather than tetrahydrofolate (H4F) as a pterin C1 carrier. However, the genome sequence of Methanosarcina species recently revealed a cluster of genes, purN, folD, glyA and metF, that are predicted to encode for H4F-specific enzymes. We show here for folD and glyA from M. barkeri that this prediction is correct: FolD (bifunctional N5,N10-methylene-H4F dehydrogenase/N5,N10-methenyl-H4F cyclohydrolase) and GlyA (serine:H4F hydroxymethyltransferase) were heterologously overproduced in Escherichia coli, purified and found to be specific for methylene-H4F and H4F, respectively (apparent Km below 5 microM). Western blot analyses and enzyme activity measurements revealed that both enzymes were synthesized in M. barkeri. The results thus indicate that M. barkeri should contain H4F, which was supported by the finding that growth of M. barkeri was dependent on folic acid and that the vitamin could be substituted by p-aminobenzoic acid, a biosynthetic precursor of H4F. From the p-aminobenzoic acid requirement, an intracellular H4F concentration of approximately 5 M was estimated. Evidence is presented that the p-aminobenzoic acid taken up by the growing cells was not required for the biosynthesis of H4SPT, which was found to be present in the cells at a concentration above 3 mM. The presence of both H4SPT and H4F in M. barkeri is in agreement with earlier isotope labeling studies indicating that there are two separate C1 pools in these methanogens.
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Affiliation(s)
- Bärbel Buchenau
- Max-Planck-Institut für terrestrische Mikrobiologie and Laboratorium für Mikrobiologie, Fachbereich Biologie, Philipps-Universität, Karl-von-Frisch-Strasse, Marburg, Germany
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24
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Martin W. Pathogenic archaebacteria: do they not exist because archaebacteria use different vitamins? Bioessays 2004; 26:592-3; author reply 593. [PMID: 15112239 DOI: 10.1002/bies.20044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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25
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Caccamo MA, Malone CS, Rasche ME. Biochemical characterization of a dihydromethanopterin reductase involved in tetrahydromethanopterin biosynthesis in Methylobacterium extorquens AM1. J Bacteriol 2004; 186:2068-73. [PMID: 15028691 PMCID: PMC374392 DOI: 10.1128/jb.186.7.2068-2073.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2003] [Accepted: 12/11/2003] [Indexed: 11/20/2022] Open
Abstract
During growth on one-carbon (C1) compounds, the aerobic alpha-proteobacterium Methylobacterium extorquens AM1 synthesizes the tetrahydromethanopterin (H4MPT) derivative dephospho-H4MPT as a C1 carrier in addition to tetrahydrofolate. The enzymes involved in dephospho-H4MPT biosynthesis have not been identified in bacteria. In archaea, the final step in the proposed pathway of H4MPT biosynthesis is the reduction of dihydromethanopterin (H2MPT) to H4MPT, a reaction analogous to the reaction of the bacterial dihydrofolate reductase. A gene encoding a dihydrofolate reductase homolog has previously been reported for M. extorquens and assigned as the putative H2MPT reductase gene (dmrA). In the present work, we describe the biochemical characterization of H2MPT reductase (DmrA), which is encoded by dmrA. The gene was expressed with a six-histidine tag in Escherichia coli, and the recombinant protein was purified by nickel affinity chromatography and gel filtration. Purified DmrA catalyzed the NAD(P)H-dependent reduction of H2MPT with a specific activity of 2.8 micromol of NADPH oxidized per min per mg of protein at 30 degrees C and pH 5.3. Dihydrofolate was not a substrate for DmrA at the physiological pH of 6.8. While the existence of an H2MPT reductase has been proposed previously, this is the first biochemical evidence for such an enzyme in any organism, including archaea. Curiously, no DmrA homologs have been identified in the genomes of known methanogenic archaea, suggesting that bacteria and archaea produce two evolutionarily distinct forms of dihydromethanopterin reductase. This may be a consequence of different electron donors, NAD(P)H versus reduced F420, used, respectively, in bacteria and methanogenic archaea.
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Affiliation(s)
- Marco A Caccamo
- Microbiology and Cell Science Department, University of Florida, Gainesville, Florida 32611-0700, USA
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26
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Irimia A, Madern D, Zaccaï G, Vellieux FMD. Methanoarchaeal sulfolactate dehydrogenase: prototype of a new family of NADH-dependent enzymes. EMBO J 2004; 23:1234-44. [PMID: 15014443 PMCID: PMC381418 DOI: 10.1038/sj.emboj.7600147] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2003] [Accepted: 02/06/2004] [Indexed: 11/09/2022] Open
Abstract
The crystal structure of the sulfolactate dehydrogenase from the hyperthermophilic and methanogenic archaeon Methanocaldococcus jannaschii was solved at 2.5 A resolution (PDB id. 1RFM). The asymmetric unit contains a tetramer of tight dimers. This structure, complexed with NADH, does not contain a cofactor-binding domain with 'Rossmann-fold' topology. Instead, the tertiary and quaternary structures indicate a novel fold. The NADH is bound in an extended conformation in each active site, in a manner that explains the pro-S specificity. Cofactor binding involves residues belonging to both subunits within the tight dimers, which are therefore the smallest enzymatically active units. The protein was found to be a homodimer in solution by size-exclusion chromatography, analytical ultracentrifugation and small-angle neutron scattering. Various compounds were tested as putative substrates. The results indicate the existence of a substrate discrimination mechanism, which involves electrostatic interactions. Based on sequence homology and phylogenetic analyses, several other enzymes were classified as belonging to this novel family of homologous (S)-2-hydroxyacid dehydrogenases.
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Affiliation(s)
- Adriana Irimia
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale J-P Ebel CEA CNRS UJF, Grenoble, France
| | - Dominique Madern
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale J-P Ebel CEA CNRS UJF, Grenoble, France
| | - Giuseppe Zaccaï
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale J-P Ebel CEA CNRS UJF, Grenoble, France
- Institut Laue Langevin, Grenoble, France
| | - Frédéric MD Vellieux
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale J-P Ebel CEA CNRS UJF, Grenoble, France
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale J-P Ebel CEA CNRS UJF, UMR-5075, 41 rue Jules Horowitz, 38027 Grenoble Cedex 01, France. Tel.: +33 438 789 605; Fax: +33 438 785 494; E-mail:
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Rasche ME, Havemann SA, Rosenzvaig M. Characterization of two methanopterin biosynthesis mutants of Methylobacterium extorquens AM1 by use of a tetrahydromethanopterin bioassay. J Bacteriol 2004; 186:1565-70. [PMID: 14973120 PMCID: PMC344399 DOI: 10.1128/jb.186.5.1565-1570.2004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2003] [Accepted: 11/12/2003] [Indexed: 11/20/2022] Open
Abstract
An enzymatic assay was developed to measure tetrahydromethanopterin (H(4)MPT) levels in wild-type and mutant cells of Methylobacterium extorquens AM1. H(4)MPT was detectable in wild-type cells but not in strains with a mutation of either the orf4 or the dmrA gene, suggesting a role for these two genes in H(4)MPT biosynthesis. The protein encoded by orf4 catalyzed the reaction of ribofuranosylaminobenzene 5'-phosphate synthase, the first committed step of H(4)MPT biosynthesis. These results provide the first biochemical evidence for H(4)MPT biosynthesis genes in bacteria.
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Affiliation(s)
- Madeline E Rasche
- Microbiology and Cell Science Department, University of Florida, Gainesville, Florida 32611-0700, USA.
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28
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Makarova KS, Koonin EV. Comparative genomics of Archaea: how much have we learned in six years, and what's next? Genome Biol 2003; 4:115. [PMID: 12914651 PMCID: PMC193635 DOI: 10.1186/gb-2003-4-8-115] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Archaea comprise one of the three distinct domains of life (with bacteria and eukaryotes). With 16 complete archaeal genomes sequenced to date, comparative genomics has revealed a conserved core of 313 genes that are represented in all sequenced archaeal genomes, plus a variable 'shell' that is prone to lineage-specific gene loss and horizontal gene exchange. The majority of archaeal genes have not been experimentally characterized, but novel functional pathways have been predicted.
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Affiliation(s)
- Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
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29
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Martin W, Russell MJ. On the origins of cells: a hypothesis for the evolutionary transitions from abiotic geochemistry to chemoautotrophic prokaryotes, and from prokaryotes to nucleated cells. Philos Trans R Soc Lond B Biol Sci 2003; 358:59-83; discussion 83-5. [PMID: 12594918 PMCID: PMC1693102 DOI: 10.1098/rstb.2002.1183] [Citation(s) in RCA: 401] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
All life is organized as cells. Physical compartmentation from the environment and self-organization of self-contained redox reactions are the most conserved attributes of living things, hence inorganic matter with such attributes would be life's most likely forebear. We propose that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH and temperature gradient between sulphide-rich hydrothermal fluid and iron(II)-containing waters of the Hadean ocean floor. The naturally arising, three-dimensional compartmentation observed within fossilized seepage-site metal sulphide precipitates indicates that these inorganic compartments were the precursors of cell walls and membranes found in free-living prokaryotes. The known capability of FeS and NiS to catalyse the synthesis of the acetyl-methylsulphide from carbon monoxide and methylsulphide, constituents of hydrothermal fluid, indicates that pre-biotic syntheses occurred at the inner surfaces of these metal-sulphide-walled compartments, which furthermore restrained reacted products from diffusion into the ocean, providing sufficient concentrations of reactants to forge the transition from geochemistry to biochemistry. The chemistry of what is known as the RNA-world could have taken place within these naturally forming, catalyticwalled compartments to give rise to replicating systems. Sufficient concentrations of precursors to support replication would have been synthesized in situ geochemically and biogeochemically, with FeS (and NiS) centres playing the central catalytic role. The universal ancestor we infer was not a free-living cell, but rather was confined to the naturally chemiosmotic, FeS compartments within which the synthesis of its constituents occurred. The first free-living cells are suggested to have been eubacterial and archaebacterial chemoautotrophs that emerged more than 3.8 Gyr ago from their inorganic confines. We propose that the emergence of these prokaryotic lineages from inorganic confines occurred independently, facilitated by the independent origins of membrane-lipid biosynthesis: isoprenoid ether membranes in the archaebacterial and fatty acid ester membranes in the eubacterial lineage. The eukaryotes, all of which are ancestrally heterotrophs and possess eubacterial lipids, are suggested to have arisen ca. 2 Gyr ago through symbiosis involving an autotrophic archaebacterial host and a heterotrophic eubacterial symbiont, the common ancestor of mitochondria and hydrogenosomes. The attributes shared by all prokaryotes are viewed as inheritances from their confined universal ancestor. The attributes that distinguish eubacteria and archaebacteria, yet are uniform within the groups, are viewed as relics of their phase of differentiation after divergence from the non-free-living universal ancestor and before the origin of the free-living chemoautotrophic lifestyle. The attributes shared by eukaryotes with eubacteria and archaebacteria, respectively, are viewed as inheritances via symbiosis. The attributes unique to eukaryotes are viewed as inventions specific to their lineage. The origin of the eukaryotic endomembrane system and nuclear membrane are suggested to be the fortuitous result of the expression of genes for eubacterial membrane lipid synthesis by an archaebacterial genetic apparatus in a compartment that was not fully prepared to accommodate such compounds, resulting in vesicles of eubacterial lipids that accumulated in the cytosol around their site of synthesis. Under these premises, the most ancient divide in the living world is that between eubacteria and archaebacteria, yet the steepest evolutionary grade is that between prokaryotes and eukaryotes.
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Affiliation(s)
- William Martin
- Institut für Botanik III, Heinrich-Heine Universitaet Düsseldorf, Universitätsstrasse 1, 40225 Düsseldorf, Germany.
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30
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Scott JW, Rasche ME. Purification, overproduction, and partial characterization of beta-RFAP synthase, a key enzyme in the methanopterin biosynthesis pathway. J Bacteriol 2002; 184:4442-8. [PMID: 12142414 PMCID: PMC135262 DOI: 10.1128/jb.184.16.4442-4448.2002] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanopterin is a folate analog involved in the C1 metabolism of methanogenic archaea, sulfate-reducing archaea, and methylotrophic bacteria. Although a pathway for methanopterin biosynthesis has been described in methanogens, little is known about the enzymes and genes involved in the biosynthetic pathway. The enzyme beta-ribofuranosylaminobenzene 5'-phosphate synthase (beta-RFAP synthase) catalyzes the first unique step to be identified in the pathway of methanopterin biosynthesis, namely, the condensation of p-aminobenzoic acid with phosphoribosylpyrophosphate to form beta-RFAP, CO2, and inorganic pyrophosphate. The enzyme catalyzing this reaction has not been purified to homogeneity, and the gene encoding beta-RFAP synthase has not yet been identified. In the present work, we report on the purification to homogeneity of beta-RFAP synthase. The enzyme was purified from the methane-producing archaeon Methanosarcina thermophila, and the N-terminal sequence of the protein was used to identify corresponding genes from several archaea, including the methanogen Methanococcus jannaschii and the sulfate-reducing archaeon Archaeoglobus fulgidus. The putative beta-RFAP synthase gene from A. fulgidus was expressed in Escherichia coli, and the enzymatic activity of the recombinant gene product was verified. A BLAST search using the deduced amino acid sequence of the beta-RFAP synthase gene identified homologs in additional archaea and in a gene cluster required for C1 metabolism by the bacterium Methylobacterium extorquens. The identification of a gene encoding a potential beta-RFAP synthase in M. extorquens is the first report of a putative methanopterin biosynthetic gene found in the Bacteria and provides evidence that the pathways of methanopterin biosynthesis in Bacteria and Archaea are similar.
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Affiliation(s)
- Joseph W Scott
- Microbiology and Cell Science Department, University of Florida, Gainesville, Florida 32611-0700, USA
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Abstract
Glutathione metabolism is associated with oxygenic cyanobacteria and the oxygen-utilizing purple bacteria, but is absent in many other prokaryotes. This review focuses on novel thiols found in those bacteria lacking glutathione. Included are glutathione amide and its perthiol, produced by phototrophic purple sulfur bacteria and apparently involved in their sulfide metabolism. Among archaebacteria, coenzyme M (2-mercaptoethanesulfonic acid) and coenzyme B (7-mercaptoheptanoylthreonine phosphate) play central roles in the anaerobic production of CH4 and associated energy conversion by methanogens, whereas the major thiol in the aerobic phototrophic halobacteria is gamma-glutamylcysteine. The highly aerobic actinomycetes produce mycothiol, a conjugate of N-acetylcysteine with a pseudodisaccharide of glucosamine and myo-inositol, AcCys-GlcNalpha(1 --> 1)Ins, which appears to play an antioxidant role similar to glutathione. Ergothioneine, also produced by actinomycetes, remains a mystery despite many years of study. Available data on the biosynthesis and metabolism of these and other novel thiols is summarized and key areas for additional study are identified.
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Affiliation(s)
- R C Fahey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA.
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