... moiety of A76 maintains the appropriate orientation of the carboxyl group of the amino acid for Pa.On GluRS, in the absence of tRNA, the Kmvalue of Glu in the ATP–PPi exchange reaction increases ... A˚. These distances within0.9 A˚ of the distance of 12.8 A˚ in ArgRS indicate that, in these aaRSs, this space is the binding site of the adenosine moiety of ATP, and in E. coli Cys-tRNAsynthetase ... the adenosine moiety of the reported aminoacyl-AMP analogs may be somewhatperturbed by the strong binding of the aminoacylmoiety on the aminoacyl-tRNA synthetase. The con-formation of the sulfamoyl...