title: Mechanistic Studies of the Radical S-Adenosyl-L-methionine Enzyme 4-Demethylwyosine Synthase Reveal the Site of Hydrogen Atom Abstraction.
abstract: TYW1 catalyzes the formation of 4-demethylwyosine via the condensation of N-methylguanosine (m¹G) with carbons 2 and 3 of pyruvate. In this study, labeled transfer ribonucleic acid (tRNA) and pyruvate were utilized to determine the site of hydrogen atom abstraction and regiochemistry of the pyruvate addition. tRNA containing a ²H-labeled m¹G methyl group was used to identify the methyl group of m¹G as the site of hydrogen atom abstraction by 5'-deoxyadenosyl radical. [2-¹³C₁-3,3,3-²H₃]Pyruvate was used to demonstrate retention of all the pyruvate protons, indicating that C2 of pyruvate forms the bridging carbon of the imidazoline ring and C3 the methyl.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Street, Tucson, Arizona 85721-0088, United States.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: Young
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona, 1041 East Lowell Street, Tucson, Arizona 85721-0088, United States.
authors.forename: Vahe
authors.initials: V
authors.lastname: Bandarian
mesh_terms: D019843:Archaeal Proteins / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D002250:Carbon Radioisotopes; D002262:Carboxy-Lyases / Q000737:chemistry / Q000378:metabolism*; D020134:Catalytic Domain; D003903:Deuterium; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism; D006151:Guanosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D017017:Methanococcus / Q000201:enzymology; D008745:Methylation; D008958:Models, Molecular; D019289:Pyruvic Acid / Q000737:chemistry / Q000378:metabolism; D019642:RNA, Archaeal / Q000737:chemistry / Q000378:metabolism; D012360:RNA, Transfer, Phe / Q000737:chemistry / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000737:chemistry / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: C569459:4-demethylwyosine; D019843:Archaeal Proteins; D002250:Carbon Radioisotopes; D005609:Free Radicals; D007506:Iron-Sulfur Proteins; D019642:RNA, Archaeal; D012360:RNA, Transfer, Phe; D006151:Guanosine; C020770:1-methylguanosine; D012436:S-Adenosylmethionine; D019289:Pyruvic Acid; D003903:Deuterium; D002262:Carboxy-Lyases