Identification of an Alternative Nucleoside Triphosphate: 5′-Deoxyadenosylcobinamide Phosphate Nucleotidyltransferase in<i>Methanobacterium thermoautotrophicum</i>ΔH

Thomas, Michael G.; Escalante‐Semerena, Jorge C.

doi:10.1128/jb.182.15.4227-4233.2000

Cited by 36 publications

(64 citation statements)

References 43 publications

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“…Other New Members of the B 12 Regulon Related to the CBL Biosynthesis-The 1,2-propanediol utilization operon pdu of S. typhimurium includes the pduX gene of unknown function (44). Here we found that some Gram-positive bacteria, namely three clostridia, L. monocytogenes, D. halfniense, and H. mobilis, contain the pduX genes located within the CBL gene clusters, usually adjacent to the cobD gene (Table I).…”

Section: Table 1 Cobalamin Biosynthesis and Transport Genes And B12-ementioning

confidence: 70%

Comparative Genomics of the Vitamin B12 Metabolism and Regulation in Prokaryotes

Rodionov

Vitreschak

Mironov

et al. 2003

Journal of Biological Chemistry

409

426

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Using comparative analysis of genes, operons, and regulatory elements, we describe the cobalamin (vitamin B 12 ) biosynthetic pathway in available prokaryotic genomes. Here we found a highly conserved RNA secondary structure, the regulatory B12 element, which is widely distributed in the upstream regions of cobalamin biosynthetic/transport genes in eubacteria. In addition, the binding signal (CBL-box) for a hypothetical B 12 regulator was identified in some archaea. A search for B12 elements and CBL-boxes and positional analysis identified a large number of new candidate B 12 -regulated genes in various prokaryotes. Among newly assigned functions associated with the cobalamin biosynthesis, there are several new types of cobalt transporters, ChlI and ChlD subunits of the CobN-dependent cobaltochelatase complex, cobalt reductase BluB, adenosyltransferase PduO, several new proteins linked to the lower ligand assembly pathway, L-threonine kinase PduX, and a large number of other hypothetical proteins. Most missing genes detected within the cobalamin biosynthetic pathways of various bacteria were identified as nonorthologous substitutes. The variable parts of the cobalamin metabolism appear to be the cobalt transport and insertion, the CobG/CbiG-and CobF/CbiD-catalyzed reactions, and the lower ligand synthesis pathway. The most interesting result of analysis of B12 elements is that B 12 -independent isozymes of the methionine synthase and ribonucleotide reductase are regulated by B12 elements in bacteria that have both B 12 -dependent and B 12 -independent isozymes. Moreover, B 12 regulons of various bacteria are thought to include enzymes from known B 12 -dependent or alternative pathways. Cobalamin (CBL),1 along with chlorophyll, heme, siroheme, and coenzyme F 430 , constitute a class of the most structurally complex cofactors synthesized by bacteria. The distinctive feature of these cofactors is their tetrapyrrole-derived framework with a centrally chelated metal ion (cobalt, magnesium, iron, or nickel). Methylcobalamin and Ado-CBL, two derivatives of vitamin B 12 (cyanocobalamin) with different upper axial ligands, are essential cofactors for several important enzymes that catalyze a variety of transmethylation and rearrangement reactions. Among the most prominent vitamin B 12 -dependent enzymes in bacteria and archaea are the methionine synthase isozyme MetH from enteric bacteria; the ribonucleotide reductase isozyme NrdJ from deeply rooted eubacteria and archaea; diol dehydratases and ethanolamine ammonia lyase from enteric bacteria involved in anaerobic glycerol, 1,2-propanediol, and ethanolamine fermentation; glutamate and methylmalonyl-CoA mutases from clostridia and streptomycetes; and various CBL-dependent methyltransferases from methane-producing archaea (1-5).Most prokaryotic organisms as well as animals (including humans) and protists have enzymes that require CBL as cofactor, whereas plants and fungi are thought not to use it. Among the CBL-utilizing organisms, only some bacterial and archaeal species ...

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Section: Table 1 Cobalamin Biosynthesis and Transport Genes And B12-ementioning

confidence: 70%

Comparative Genomics of the Vitamin B12 Metabolism and Regulation in Prokaryotes

Rodionov

Vitreschak

Mironov

et al. 2003

Journal of Biological Chemistry

409

426

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“…Therefore, the addition of acetate to minimal medium might reduce the total cobamide demand and allow for growth on reduced concentrations of cobamide. To verify this hypothesis, the concentrations of cobamides in extracts of wild type and JJ117 were determined with the indicator strain S. enterica serovar Typhimurium TR6583 (Maggio-Hall and Escalante-Semerena 1999, Thomas and Escalante-Semerena 2000). Detectible but low amounts of cobamides were found in extracts of the mutant JJ117 (Figure 6A).…”

Section: Quantification Of Cobamide In the Wild Type And Jj117mentioning

confidence: 96%

“…Of this, 4 ml was concentrated to dryness in a high speed vac (Uniequip, Martinsried, Germany) and resuspended in 50 µl of distilled water. The cobamide concentration was estimated as described by Maggio-Hall and Escalante-Semerena (1999) and Thomas and Escalante-Semerena (2000). For this experiment, Vogel-Bonner medium overlaid by 3 ml of medium containing Salmonella enterica serovar Typhimurium TR6583 [metE205 ara-9] or JE1299 [metE205 ara-9 btuB7::MudJ] were spotted with 2.5 or 5 µl of various dilutions of the methanococcal extracts.…”

Section: Measurement Of Cobamide Concentrationmentioning

confidence: 99%

“…Labeling studies and comparative analyses of genomic sequences suggest many similarities of the cobamide biosynthetic pathway in archaea to that in bacteria (Eisenreich andBacher 1991, Selkov et al 1997). However, there is direct evidence for only a few of the steps (Scherer et al 1984, Blanche et al 1991, Thomas and Escalante-Semerena 2000, Woodson et al 2003, Woodson and Escalante-Semerena 2004.…”

Section: Introductionmentioning

confidence: 99%

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Role of the precorrin 6‐X reductase gene in cobamide biosynthesis in Methanococcus maripaludis

Kim

Major

Whitman

2005

Archaea

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SummaryIn Methanococcus maripaludis strain JJ, deletion of the homolog to cbiJ, which encodes the corrin biosynthetic enzyme precorrin 6-X reductase, yielded an auxotroph that required either cobamide or acetate for good growth. This phenotype closely resembled that of JJ117, a mutant in which tandem repeats were introduced into the region immediately downstream of the homolog of cbiJ. Mutant JJ117 also produced low quantities of cobamides, about 15 nmol g -1 protein or 1-2% of the amount found in wild-type cells. These results confirm the role of the cbiJ homolog in cobamide biosynthesis in the Archaea and suggest the presence of low amounts of a bypass activity in these organisms.

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“…Salvaging of Cby requires first its conversion to adenosylcobyric acid (AdoCby) by the ATP : co(I)rrinoid adenosylransferase (CobA) enzyme, followed by its conversion to adenosylcobinamide-phosphate (AdoCbi-P) by the Cbi-P synthase (CbiB) enzyme (Brushaber et al, 1998;Thomas & Escalante-Semerena, 2000). In contrast to Cby, Cbi is directly phosphorylated by CobU, the bifunctional kinase/guanylyltransferase enzyme whose kinase activity is dedicated to Cbi salvaging (Thomas & Escalante-Semerena, 2000). The lower ligand base in the structure shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

2004

Self Cite

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In Salmonella enterica, the last step of the synthesis of adenosylcobamide is catalysed by the cobalamin synthase enzyme encoded by the cobS gene of this bacterium. Overexpression of the S. enterica cobS gene in Escherichia coli elicited the accumulation of the phage shock protein PspA, a protein whose expression has been linked to membrane stress. Resolution of inner and outer membranes of S. enterica by isopycnic density ultracentrifugation showed CobS activity associated with the inner membrane, a result that was confirmed using antibodies against CobS. Computer analysis of the predicted amino acid sequence of CobS suggested it was an integral membrane protein.Results of experiments performed with strains carrying plasmids encoding CobS-alkaline phosphatase or CobS-b-galactosidase protein fusions were consistent with the membrane localization of the CobS protein. Modifications to the predicted model were made based on data obtained from experiments using protein fusions. The function encoded by the cobS orthologue in the methanogenic archaeon Methanobacterium thermoautotrophicum strain DH compensated for the lack of CobS during cobalamin synthesis in cobS strains of S. enterica. Cobalamin synthase activity was also detected in a membrane preparation of M. thermoautotrophicum. It was concluded that the assembly of the nucleotide loop of adenosylcobamides in archaea and bacteria is a membrane-associated process. Possible reasons for the association of adenosylcobamide biosynthetic enzymes with the cell membrane are discussed.

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Identification of an Alternative Nucleoside Triphosphate: 5′-Deoxyadenosylcobinamide Phosphate Nucleotidyltransferase inMethanobacterium thermoautotrophicumΔH

Cited by 36 publications

References 43 publications

Comparative Genomics of the Vitamin B12 Metabolism and Regulation in Prokaryotes

Comparative Genomics of the Vitamin B12 Metabolism and Regulation in Prokaryotes

Role of the precorrin 6‐X reductase gene in cobamide biosynthesis in Methanococcus maripaludis

The last step in coenzyme B12 synthesis is localized to the cell membrane in bacteria and archaea

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