Vitamin B12in the spotlight again.
The ability of cobalamin to coordinate different upper axial ligands gives rise to a diversity of reactivity. Traditionally, adenosylcobalamin is associated with radical-based rearrangements, and methylcobalamin with methyl cation transfers. Recently, however, a new role for adenosylcobalamin has been discovered as a light sensor, and a methylcobalamin-dependent enzyme has been identified that is suggested to transfer a methyl anion. Additionally, recent studies have provided a wealth of new information about a third class of cobalamin-dependent enzymes that do not appear to use an upper ligand. They function in reductive dehalogenations and epoxide reduction reactions. Finally, mechanistic details are beginning to emerge about the cobalamin-dependent S-adenosylmethionine radical enzyme superfamily for which the role of cobalamin has been largely enigmatic.
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. Electronic address: jb_rabb@mit.edu.
Jennifer
J
Bridwell-Rabb
Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. Electronic address: cdrennan@mit.edu.
Catherine L
CL
Drennan
D003038:Cobamides / Q000737:chemistry / Q000378:metabolism; D004798:Enzymes / Q000737:chemistry / Q000378:metabolism; D008027:Light; D012436:S-Adenosylmethionine / Q000378:metabolism; D014805:Vitamin B 12 / Q000737:chemistry / Q000378:metabolism
D003038:Cobamides; D004798:Enzymes; D012436:S-Adenosylmethionine; C000913:cobamamide; D014805:Vitamin B 12