title: Vitamin B12-derivatives-enzyme cofactors and ligands of proteins and nucleic acids.
abstract: B(12)-cofactors play important roles in the metabolism of microorganisms, animals and humans. Microorganisms are the only natural sources of B(12)-derivatives, and the latter are "vitamins" for other B(12)-requiring organisms. Some B(12)-dependent enzymes catalyze complex isomerisation reactions, such as methylmalonyl-CoA mutase. They need coenzyme B(12), an organometallic B(12)-derivative, to induce enzymatic radical reactions. Another group of widely relevant enzymes catalyzes the transfer of methyl groups, such as methionine synthase, which uses methylcobalamin as cofactor. This tutorial review covers structure and reactivity of B(12)-derivatives and structural aspects of their interactions with proteins and nucleotides, which are crucial for the efficient catalysis by the important B(12)-dependent enzymes, and for achieving and regulating uptake and transport of B(12)-derivatives.
authors.affiliation: Institute of Molecular Biosciences, University of Graz, Humboldtstr. 50/3, Graz, A-8010, Austria.
authors.forename: Karl
authors.initials: K
authors.lastname: Gruber
authors.forename: Barbara
authors.initials: B
authors.lastname: Puffer
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kräutler
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000378:metabolism; D000085:Acetates / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D003035:Cobalt / Q000378:metabolism; D003067:Coenzymes / Q000737:chemistry / Q000378:metabolism*; D045728:Corrinoids / Q000737:chemistry / Q000378:metabolism; D004981:Ethanolamine Ammonia-Lyase / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008024:Ligands; D008765:Methylmalonyl-CoA Mutase / Q000378:metabolism; D008780:Methyltransferases / Q000378:metabolism; D009696:Nucleic Acids / Q000737:chemistry / Q000378:metabolism*; D011506:Proteins / Q000737:chemistry / Q000378:metabolism*; D014805:Vitamin B 12 / Q000031:analogs & derivatives / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000085:Acetates; D003067:Coenzymes; D045728:Corrinoids; D008024:Ligands; D009696:Nucleic Acids; D011506:Proteins; D003035:Cobalt; C019476:mecobalamin; D008780:Methyltransferases; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D004981:Ethanolamine Ammonia-Lyase; D008765:Methylmalonyl-CoA Mutase; D014805:Vitamin B 12