title: S-adenosylmethionine as an oxidant: the radical SAM superfamily.
abstract: A recently discovered superfamily of enzymes function using chemically novel mechanisms, in which S-adenosylmethionine (SAM) serves as an oxidizing agent in DNA repair and the biosynthesis of vitamins, coenzymes and antibiotics. Members of this superfamily, the radical SAM enzymes, are related by the cysteine motif CxxxCxxC, which nucleates the [4Fe-4S] cluster found in each. A common thread in the novel chemistry of these proteins is the use of a strong reducing agent--a low-potential [4Fe-4S](1+) cluster--to generate a powerful oxidizing agent, the 5'-deoxyadenosyl radical, from SAM. Recent results are beginning to determine the unique biochemistry for some of the radical SAM enzymes, for example, lysine 2,3 aminomutase, pyruvate formate lyase activase and biotin synthase.
authors.affiliation: Department of Biochemistry, University of Wisconsin-Madison, 1710 University Avenue, Madison, WI 53726, USA.
authors.forename: Susan C
authors.initials: SC
authors.lastname: Wang
authors.forename: Perry A
authors.initials: PA
authors.lastname: Frey
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D003038:Cobamides / Q000378:metabolism; D003304:Coproporphyrinogen Oxidase / Q000378:metabolism; D019175:DNA Methylation; D004798:Enzymes / Q000378:metabolism; D005578:Fosfomycin / Q000096:biosynthesis; D005609:Free Radicals / Q000378:metabolism; D019751:Intramolecular Transferases / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008956:Models, Chemical; D008958:Models, Molecular; D063065:Organophosphonates / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism
chemical_list: D000123:Acetyltransferases; D001426:Bacterial Proteins; D003038:Cobamides; D003304:Coproporphyrinogen Oxidase; D004798:Enzymes; D005578:Fosfomycin; D005609:Free Radicals; D019751:Intramolecular Transferases; D007501:Iron; D063065:Organophosphonates; D016877:Oxidants; D011506:Proteins; D012436:S-Adenosylmethionine; D013455:Sulfur; C519566:2-hydroxyethyl phosphonate; C109194:HemN protein, Bacteria; C040285:pyruvate formate-lyase activating enzyme; C022560:formate C-acetyltransferase; C088014:spore photoproduct lyase; C021518:lysine 2,3-aminomutase; C000913:cobamamide