In molecular biology, cob(I)yrinic acid a,c-diamide adenosyltransferase (also known as ATP:cob(I)alamin adenosyltransferase or ATP:corrinoid adenosyltransferase) is an
enzyme which
catalyses the conversion of
cobalamin (vitamin B12) into one of its coenzyme forms,
adenosylcobalamin (coenzyme B12, AdoCbl).
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.
ATP:cob(I)alamin adenosyltransferases are classed into three groups: CobA-type,
EutT-type
and PduO-type.
Each of the three enzyme types appears to be specialised for particular AdoCbl-dependent
enzymes
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...
or for the
de novo synthesis
In chemistry, ''de novo'' synthesis () refers to the synthesis of complex molecules from simple molecules such as sugars or amino acids, as opposed to recycling after partial degradation. For example, nucleotides are not needed in the diet as the ...
of AdoCbl. PduO and EutT are distantly related, sharing short
conserved motifs, while CobA is
evolutionarily
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation t ...
unrelated and is an example of
convergent evolution.
The CobA group includes the ATP:cob(I)alamin adenosyltransferases CobA (''
Salmonella typhimurium''), CobO (''
Pseudomonas denitrificans''), and ButR (''Escherichia coli''). There is a high degree of
sequence identity between these
proteins.
CobA is responsible for attaching the adenosyl moiety from ATP to the cobalt ion of the
corrin ring, necessary for the conversion of cobalamin to adenosylcobalamin.
PduO functions to convert cobalamin to AdoCbl for 1,2-propanediol
degradation,
while EutT produces AdoCbl for
ethanolamine
Ethanolamine (2-aminoethanol, monoethanolamine, ETA, or MEA) is an organic chemical compound with the formula or . The molecule is bifunctional, containing both a primary amine and a primary alcohol. Ethanolamine is a colorless, viscous liquid wit ...
utilisation.
Synonyms
This enzyme is also known as:
* Cobalamin adenosyltransferase
* ATP:cob(I)alamin adenosyltransferase
* ATP:corrinoid adenosyltransferase
See also
*
Cobalamin biosynthesis
References
{{InterPro content, IPR002779
Protein families
EC 2.5.1