title: Mechanistic studies of the tRNA-modifying enzyme QueA: a chemical imperative for the use of AdoMet as a "ribosyl" donor.
abstract: [formula: see text] The enzyme S-adenosylmethionine:tRNA ribosyltransferase-isomerase (QueA) catalyzes the penultimate step in the biosynthesis of the tRNA nucleoside queuosine, a unique ribosyl transfer from the cofactor S-adenosylmethionine (AdoMet) to a modified-tRNA precursor. The use of AdoMet in this way is fundamentally new to the chemistry of this important biological cofactor. We report here the first mechanistic studies of this remarkable enzyme, and we propose a chemical mechanism for the reaction consistent with our experimental observations.
authors.affiliation: Department of Chemistry, Portland State University, Oregon 97201, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Kinzie
authors.forename: B
authors.initials: B
authors.lastname: Thern
authors.forename: D
authors.initials: D
authors.lastname: Iwata-Reuyl
mesh_terms: D007535:Isomerases; D009682:Magnetic Resonance Spectroscopy; D009704:Nucleoside Q / Q000096:biosynthesis; D010430:Pentosyltransferases / Q000737:chemistry* / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism; D012266:Ribose / Q000378:metabolism; D012436:S-Adenosylmethionine / Q000737:chemistry*
chemical_list: D009704:Nucleoside Q; D012266:Ribose; D012436:S-Adenosylmethionine; D012343:RNA, Transfer; D010430:Pentosyltransferases; C082572:S-adenosylmethionine - tRNA ribosyltransferase-isomerase; D007535:Isomerases