Cobalt chelatase, CobT subunit (IPR006538)

Short name: CobT

Overlapping homologous superfamilies


Family relationships



These proteins are CobT subunits of the aerobic cobalt chelatase (aerobic cobalamin biosynthesis pathway). Pseudomonas denitrificans CobT has been experimentally characterised [PMID: 1917840, PMID: 1429466]. Aerobic cobalt chelatase consists of three subunits, CobT, CobN (IPR003672) and CobS (IPR006537).

Cobalamin (vitamin B12) can be complexed with metal via the ATP-dependent reactions (aerobic pathway) (e.g., in P. denitrificans) or via ATP-independent reactions (anaerobic pathway) (e.g., in Salmonella typhimurium) [PMID: 8905078, PMID: 11469861]. 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 [PMID: 11469861]. 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) [PMID: 11469861].

Nomenclature note: CobT of the aerobic pathway P. denitrificans is not a homologue of CobT of the anaerobic pathway (Salmonella typhimurium, Escherichia coli). Therefore, annotation of any members of this family as nicotinate-mononucleotide--5,6-dimethylbenzimidazole phosphoribosyltransferases is erroneous.

GO terms

Biological Process

GO:0009236 cobalamin biosynthetic process

Molecular Function

No terms assigned in this category.

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.