This view shows enzymes only for those organisms listed below, in the list of taxa known to possess the pathway. If an enzyme name is shown in bold, there is experimental evidence for this enzymatic activity.
Synonyms: vitamin B12 biosynthesis
|Superclasses:||Biosynthesis → Cofactors, Prosthetic Groups, Electron Carriers Biosynthesis → Vitamins Biosynthesis → Cobalamin Biosynthesis → Adenosylcobalamin Biosynthesis|
Some taxa known to possess this pathway include : Halobacterium sp. NRC-1 , Methanopyrus kandleri AV19 , Methanosarcina mazei Go1 , Methanothermobacter thermautotrophicus Delta H , Rhodobacter sphaeroides 2.4.1
De novo synthesis of cobamides requires a great deal of genetic information, which is only found in some prokaryotes. Many bacterial species do not have the full genetic information required for de novo biosynthesis of coenzyme B12, but can synthesize cobalamin when supplied with cobinamide, a stable cobamide that is not a true intermediate of the de novo pathway [Ford55, Lawrence96].
In order to process cobinamide to coenzyme B12, it has to be converted into a real intermediate of the pathway. In most bacteria this is done by the attachment of the upper ligand 5'-deoxyadenosine to yield adenosylcobinamide, followed by phosphorylation to yield adenosyl-cobinamide phosphate, an intermediate of the de novo biosynthetic pathway (see adenosylcobalamin salvage from cobinamide I).
Archaebacteria utilze a different salvage pathway, where adenosylcobinamide is first converted to adenosylcobyrate by EC 18.104.22.168, adenosylcobinamide hydrolase (CbiZ). Adenosylcobyrate is then converted to adenosyl-cobinamide phosphate by the action of EC 22.214.171.124, adenosylcobinamide-phosphate synthase (CbiB) [Woodson04].
Archaea possess several enzymes that are non-orthologous replacements for the bacterial genes. For example, the archaeal cobZ catalyzes the same reaction as the bacterial cobC [Zayas06], and the archaeal cobY replaces the bacterial cobP and cobU [Woodson03a]. Some archaea carry the cbiS gene, which encodes a fusion of the genes cbiZ and cobZ [Woodson06].
There are many bacterial species that carry the genes of the archaeal salvage pathway. It is believed that the origin of the genes is archaeal, and that the bacterial genes were acquired by horizontal gene transfer [Gray08]
Variants: adenosylcobalamin biosynthesis I (early cobalt insertion) , adenosylcobalamin biosynthesis II (late cobalt incorporation) , adenosylcobalamin salvage from cobalamin , adenosylcobalamin salvage from cobinamide I
Gray08: Gray MJ, Tavares NK, Escalante-Semerena JC (2008). "The genome of Rhodobacter sphaeroides strain 2.4.1 encodes functional cobinamide salvaging systems of archaeal and bacterial origins." Mol Microbiol 70(4);824-36. PMID: 18808385
Woodson03: Woodson JD, Zayas CL, Escalante-Semerena JC (2003). "A new pathway for salvaging the coenzyme B12 precursor cobinamide in archaea requires cobinamide-phosphate synthase (CbiB) enzyme activity." J Bacteriol 185(24);7193-201. PMID: 14645280
Woodson03a: Woodson JD, Peck RF, Krebs MP, Escalante-Semerena JC (2003). "The cobY gene of the archaeon Halobacterium sp. strain NRC-1 is required for de novo cobamide synthesis." J Bacteriol 185(1);311-6. PMID: 12486068
Woodson04: Woodson JD, Escalante-Semerena JC (2004). "CbiZ, an amidohydrolase enzyme required for salvaging the coenzyme B12 precursor cobinamide in archaea." Proc Natl Acad Sci U S A 101(10);3591-6. PMID: 14990804
Woodson06: Woodson JD, Escalante-Semerena JC (2006). "The cbiS gene of the archaeon Methanopyrus kandleri AV19 encodes a bifunctional enzyme with adenosylcobinamide amidohydrolase and alpha-ribazole-phosphate phosphatase activities." J Bacteriol 188(12);4227-35. PMID: 16740929
Zayas06: Zayas CL, Woodson JD, Escalante-Semerena JC (2006). "The cobZ gene of Methanosarcina mazei Go1 encodes the nonorthologous replacement of the alpha-ribazole-5'-phosphate phosphatase (CobC) enzyme of Salmonella enterica." J Bacteriol 188(7);2740-3. PMID: 16547066
Blanche91: Blanche F, Debussche L, Famechon A, Thibaut D, Cameron B, Crouzet J (1991). "A bifunctional protein from Pseudomonas denitrificans carries cobinamide kinase and cobinamide phosphate guanylyltransferase activities." J Bacteriol 1991;173(19);6052-7. PMID: 1655696
Blanche95: Blanche F., Cameron B., Crouzet J., Debussche L., Thibaut D., Vuilhorgne M., Leeper F. J., Battersby A. R. (1995). "Vitamin B12: how the problem of its biosynthesis was solved." Angewandte Chemie. International edition in English 34(4): 383-411.
Buan06: Buan NR, Rehfeld K, Escalante-Semerena JC (2006). "Studies of the CobA-type ATP:Co(I)rrinoid adenosyltransferase enzyme of Methanosarcina mazei strain Go1." J Bacteriol 188(10);3543-50. PMID: 16672609
Cameron91: Cameron B, Blanche F, Rouyez MC, Bisch D, Famechon A, Couder M, Cauchois L, Thibaut D, Debussche L, Crouzet J (1991). "Genetic analysis, nucleotide sequence, and products of two Pseudomonas denitrificans cob genes encoding nicotinate-nucleotide: dimethylbenzimidazole phosphoribosyltransferase and cobalamin (5'-phosphate) synthase." J Bacteriol 1991;173(19);6066-73. PMID: 1917841
Debussche91: Debussche L, Couder M, Thibaut D, Cameron B, Crouzet J, Blanche F (1991). "Purification and partial characterization of Cob(I)alamin adenosyltransferase from Pseudomonas denitrificans." J Bacteriol 1991;173(19);6300-2. PMID: 1917862
Hsu05: Hsu FC, Ho TJ, Lai CC, Lin CF, Chen HP (2005). "Cloning, sequencing, expression, and single-step purification of the adenosylcobinamide kinase/adenosylcobinamide-phosphate guanylyltransferase (CobU) from Salmonella typhimurium ATCC 19585." Protein Expr Purif 42(1);178-81. PMID: 15939305
MaggioHall04: Maggio-Hall LA, Claas KR, Escalante-Semerena JC (2004). "The last step in coenzyme B(12) synthesis is localized to the cell membrane in bacteria and archaea." Microbiology 150(Pt 5);1385-95. PMID: 15133100
MaggioHall99: Maggio-Hall LA, Escalante-Semerena JC (1999). "In vitro synthesis of the nucleotide loop of cobalamin by Salmonella typhimurium enzymes." Proc Natl Acad Sci U S A 96(21);11798-803. PMID: 10518530
OToole94: O'Toole GA, Trzebiatowski JR, Escalante-Semerena JC (1994). "The cobC gene of Salmonella typhimurium codes for a novel phosphatase involved in the assembly of the nucleotide loop of cobalamin." J Biol Chem 1994;269(42);26503-11. PMID: 7929373
OToole95: O'Toole GA, Escalante-Semerena JC (1995). "Purification and characterization of the bifunctional CobU enzyme of Salmonella typhimurium LT2. Evidence for a CobU-GMP intermediate." J Biol Chem 270(40);23560-9. PMID: 7559521
Raux96: Raux E, Lanois A, Levillayer F, Warren MJ, Brody E, Rambach A, Thermes C (1996). "Salmonella typhimurium cobalamin (vitamin B12) biosynthetic genes: functional studies in S. typhimurium and Escherichia coli." J Bacteriol 178(3);753-67. PMID: 8550510
Suh95: Suh S, Escalante-Semerena JC (1995). "Purification and initial characterization of the ATP:corrinoid adenosyltransferase encoded by the cobA gene of Salmonella typhimurium." J Bacteriol 177(4);921-5. PMID: 7860601
Trzebiatowski97: Trzebiatowski JR, Escalante-Semerena JC (1997). "Purification and characterization of CobT, the nicotinate-mononucleotide:5,6-dimethylbenzimidazole phosphoribosyltransferase enzyme from Salmonella typhimurium LT2." J Biol Chem 272(28);17662-7. PMID: 9211916
Zayas07: Zayas CL, Escalante-Semerena JC (2007). "Reassessment of the late steps of coenzyme B12 synthesis in Salmonella enterica: evidence that dephosphorylation of adenosylcobalamin-5'-phosphate by the CobC phosphatase is the last step of the pathway." J Bacteriol 189(6);2210-8. PMID: 17209023
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