title: Transfer RNA aminoacylation: identification of a critical ribose 2'-hydroxyl-base interaction.
abstract: To understand the relationship between tRNA architecture and specific aminoacylation by aminoacyl-tRNA synthetases, we performed kinetic assays of Escherichia coli tRNA(Pro) molecules containing single deoxynucleotide substitutions. We identified an important 2'-hydroxyl group at position U8 (of 22 positions probed). Chemical modification studies showed that this 2'-hydroxyl interacts with either the N1 or the exocyclic amine of G46 in a hydrogen bonding interaction that contributes 1.8 kcal/mol to the free energy of activation for aminoacylation. Molecular modeling of tRNA(Pro) supports the existence of this interaction. This is the first study to identify a specific ribose 2'-hydroxyl-base interaction in the core region of a tRNA molecule that makes a thermodynamically significant contribution to aminoacylation.
mesh_terms: D000215:Acylation; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D001483:Base Sequence; D003854:Deoxyribonucleotides; D004926:Escherichia coli / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012361:RNA, Transfer, Pro / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012266:Ribose; D013379:Substrate Specificity; D013816:Thermodynamics; D014529:Uridine
chemical_list: D003854:Deoxyribonucleotides; D012361:RNA, Transfer, Pro; D012266:Ribose; D000604:Amino Acyl-tRNA Synthetases; C100134:prolyl T RNA synthetase; D014529:Uridine