Cobalt chelatase

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cobalt chelatase
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Putative cobalt chelatase monomer from Desulvobrio vulgaris. [1]
Identifiers
EC no. 6.6.1.2
CAS no. 81295-49-0
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
Search
PMC articles
PubMed articles
NCBI proteins
Cobalt chelatase, CobT subunit
Identifiers
SymbolCobT
Pfam PF06213
InterPro IPR006538
Available protein structures:
Pfam   structures / ECOD  
PDB RCSB PDB; PDBe; PDBj
PDBsum structure summary

Cobalt chelatase (EC 6.6.1.2) is an enzyme that catalyzes the chemical reaction

Contents

ATP + hydrogenobyrinic acid a,c-diamide + Co2+ + H2O ADP + phosphate + cob(II)yrinic acid a,c-diamide + H+

The four substrates of this enzyme are ATP, hydrogenobyrinic acid a,c-diamide, Co 2+, and H2O; its four products are ADP, phosphate, cob(II)yrinic acid a,c-diamide, and H+.

The aerobic cobalt chelatase (aerobic cobalamin biosynthesis pathway) [2] [3] consists of three subunits, CobT, CobN (InterPro :  IPR003672 ) and CobS (InterPro :  IPR006537 ).

The macrocycle of vitamin B12 can be complexed with metal via the ATP-dependent reactions in the aerobic pathway (e.g., in Pseudomonas denitrificans ) or via ATP-independent reactions of sirohydrochlorin in the anaerobic pathway (e.g., in Salmonella typhimurium ). [4] [5] The corresponding cobalt chelatases are not homologous. However, aerobic cobalt chelatase subunits CobN and CobS are homologous to Mg-chelatase subunits BchH and BchI, respectively. [5] CobT, too, has been found to be remotely related to the third subunit of Mg-chelatase, BchD (involved in bacteriochlorophyll synthesis, e.g., in Rhodobacter capsulatus). [5]

This enzyme belongs to the family of ligases, specifically those forming nitrogen-D-metal bonds in coordination complexes. The systematic name of this enzyme class is hydrogenobyrinic-acid-a,c-diamide:cobalt cobalt-ligase (ADP-forming). Other names in common use include hydrogenobyrinic acid a,c-diamide cobaltochelatase, CobNST, and CobNCobST. This enzyme is part of the biosynthetic pathway to cobalamin (vitamin B12) in aerobic bacteria.

See also

Related Research Articles

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In molecular biology, cob(I)yrinic acid a,c-diamide adenosyltransferase EC 2.5.1.17 is an enzyme which catalyses the conversion of cobalamin into one of its coenzyme forms, adenosylcobalamin. Adenosylcobalamin is required as a cofactor for the activity of certain enzymes. AdoCbl contains an adenosyl moiety liganded to the cobalt ion of cobalamin via a covalent Co-C bond.

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References

  1. Romão, Célia V.; Ladakis, Dimitrios; Lobo, Susana A. L.; Carrondo, Maria A.; Brindley, Amanda A.; Deery, Evelyne; Matias, Pedro M.; Pickersgill, Richard W.; Saraiva, Lígia M.; Warren, Martin J. (4 January 2011). "Evolution in a family of chelatases facilitated by the introduction of active site asymmetry and protein oligomerization". Proceedings of the National Academy of Sciences. 108 (1): 97–102. doi: 10.1073/pnas.1014298108 . PMC   3017170 . PMID   21173279.
  2. Crouzet J, Cameron B, Cauchois L, Rigault S, Blanche F, Guilhot C, Levy-schil S, Rouyez MC (1991). "Genetic and sequence analyses of a Pseudomonas denitrificans DNA fragment containing two cob genes". J. Bacteriol. 173 (19): 6058–6065. doi:10.1128/jb.173.19.6058-6065.1991. PMC   208352 . PMID   1917840.
  3. Crouzet J, Cameron B, Blanche F, Thibaut D, Debussche L, Couder M (1992). "Assay, purification, and characterization of cobaltochelatase, a unique complex enzyme catalyzing cobalt insertion in hydrogenobyrinic acid a,c-diamide during coenzyme B12 biosynthesis in Pseudomonas denitrificans". J. Bacteriol. 174 (22): 7445–7451. doi:10.1128/jb.174.22.7445-7451.1992. PMC   207441 . PMID   1429466.
  4. Roth JR, Lawrence JG, Bobik TA (1996). "Cobalamin (coenzyme B12): synthesis and biological significance" (PDF). Annu. Rev. Microbiol. 50: 137–181. doi:10.1146/annurev.micro.50.1.137. PMID   8905078. S2CID   36290299. Archived from the original (PDF) on 2019-03-07.
  5. 1 2 3 Willows RD, Al-Karadaghi S, Hansson M, Fodje MN, Hansson A, Olsen JG, Gough S (2001). "Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase". J. Mol. Biol. 311 (1): 111–122. doi:10.1006/jmbi.2001.4834. PMID   11469861.

Further reading

This article incorporates text from the public domain Pfam and InterPro: IPR006538