CATH Classification

Domain Context

CATH Clusters

Superfamily P-loop containing nucleotide triphosphate hydrolases
Functional Family

Enzyme Information
Corrinoid adenosyltransferase.
based on mapping to UniProt P31570
(1) 2 ATP + 2 cob(II)alamin + a reduced flavoprotein = 2 triphosphate + 2 adenosylcob(III)alamin + an oxidized flavoprotein. (2) 2 ATP + 2 cob(II)yrinic acid a,c-diamide + a reduced flavoprotein = 2 triphosphate + 2 adenosylcob(III)yrinic acid a,c-diamide + an oxidized flavoprotein.
-!- The corrinoid adenosylation pathway comprises three steps: (i) reduction of Co(III) to Co(II) by a one-electron transfer. -!- This can occur non-enzymically in the presence of dihydroflavin nucleotides or reduced flavoproteins. -!- (ii) Co(II) is bound by corrinoid adenosyltransferase, resulting in displacement of the lower axial ligand by an aromatic residue. -!- The reduction potential of the 4-coordinate Co(II) intermediate is raised by ~250 mV compared with the free compound, bringing it to within physiological range. -!- This is followed by a second single-electron transfer from either free dihydroflavins or the reduced flavin cofactor of flavoproteins, resulting in reduction to Co(I). -!- (iii) the Co(I) conducts a nucleophilic attack on the adenosyl moiety of ATP, resulting in transfer of the deoxyadenosyl group and oxidation of the cobalt atom to Co(III) state. -!- Three types of corrinoid adenosyltransferases, not related by sequence, have been described. -!- In the anaerobic bacterium Salmonella enterica they are encoded by the cobA gene (a housekeeping enzyme involved in both adenosylcobalamin de novo biosynthesis and salvage), the pduO gene (involved in (S)-propane-1,2-diol utilization), and the eutT gene (involved in ethanolamine utilization). -!- Since EutT hydrolyzes triphosphate during catalysis, it is classified as a separate enzyme. -!- The mammalian enzyme belongs to the PduO type. -!- The enzyme can act on other corrinoids, such as cob(II)inamide.

UniProtKB Entries (1)

Salmonella enterica subsp. enterica serovar Typhimurium str. LT2
Corrinoid adenosyltransferase

PDB Structure

External Links
Organism Salmonella
Primary Citation
Three-dimensional structure of ATP:corrinoid adenosyltransferase from Salmonella typhimurium in its free state, complexed with MgATP, or complexed with hydroxycobalamin and MgATP.
Bauer, C.B., Fonseca, M.V., Holden, H.M., Thoden, J.B., Thompson, T.B., Escalante-Semerena, J.C., Rayment, I.