title: Ribozyme-catalyzed tRNA aminoacylation.
abstract: The RNA world hypothesis implies that coded protein synthesis evolved from a set of ribozyme catalyzed acyl-transfer reactions, including those of aminoacyl-tRNA synthetase ribozymes. We report here that a bifunctional ribozyme generated by directed in vitro evolution can specifically recognize an activated glutaminyl ester and aminoacylate a targeted tRNA, via a covalent aminoacyl-ribozyme intermediate. The ribozyme consists of two distinct catalytic domains; one domain recognizes the glutamine substrate and self-aminoacylates its own 5'-hydroxyl group, and the other recognizes the tRNA and transfers the aminoacyl group to the 3'-end. The interaction of these domains results in a unique pseudoknotted structure, and the ribozyme requires a change in conformation to perform the sequential aminoacylation reactions. Our result supports the idea that aminoacyl-tRNA synthetase ribozymes could have played a key role in the evolution of the genetic code and RNA-directed translation.
authors.affiliation: Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000, USA.
authors.forename: N
authors.initials: N
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Bessho
authors.forename: K
authors.initials: K
authors.lastname: Wei
authors.forename: J W
authors.initials: JW
authors.lastname: Szostak
authors.forename: H
authors.initials: H
authors.lastname: Suga
mesh_terms: D000215:Acylation; D001483:Base Sequence; D001665:Binding Sites; D020134:Catalytic Domain; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D005815:Genetic Code / Q000235:genetics; D005973:Glutamine / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D016337:RNA, Catalytic / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012343:RNA, Transfer / Q000378:metabolism*; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism*; D012351:RNA, Transfer, Gln / Q000378:metabolism; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
chemical_list: D016337:RNA, Catalytic; D012346:RNA, Transfer, Amino Acyl; D012351:RNA, Transfer, Gln; D005973:Glutamine; D012343:RNA, Transfer