title: Mechanism of tRNA-synthetase recognition: role of terminal A.
abstract: The function of the terminal A of tRNA Phe (yeast) with respect to complex formation with the cognate aminoacyl-tRNA synthetase has been studied using equilibrium and fast kinetic techniques. Removal of the terminal A influences the equilibrium parameters of the tRNA-synthetase interaction only slightly, the mechanism of complex formation, however, is changed significantly. The binding mechanism of unmodified tRNAPhe comprises a recombination step and a consecutive conformational change. In contrast, the reaction between tRNAPheCC and the cognate synthetase is characterized by a simple one step mechanism. It is concluded that the terminal A is responsible for the occurrence of the conformational change of the tRNA-synthetase complex. The conformational change is interpreted as a proper alignment of the terminal A of the tRNA to the active site of the synthetase.
mesh_terms: D000225:Adenine; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites; D007700:Kinetics; D008433:Mathematics; D010649:Phenylalanine; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism; D012343:RNA, Transfer
chemical_list: D010649:Phenylalanine; D012343:RNA, Transfer; D000604:Amino Acyl-tRNA Synthetases; D010652:Phenylalanine-tRNA Ligase; D000225:Adenine