title: On the stereochemistry of activation of phenylalanine by phenylalanyl-tRNA synthetase from baker's yeast.
abstract: Because of its chiralic alpha-phosphorus atom adenosine 5'-O-(1-thiotriphosphate) (ATPalphaS) exists in two diastereomeric forms, arbitrarily named (A) and (B). For phenylalanyl-tRNA synthetase ATPalphaS (A) is a substrate whereas ATPalphaS (B) is neither a substrate nor an inhibitor. During the ATPalphaS (A)/PPi exchange reaction with phenylalanyl-tRNA synthetase the configuration at the alpha-phosphorus is retained. The mechanistic implications of these findings are discussed. Preliminary investigations with several other aminoacyl-tRNA synthetases show that the stereochemical requirement with respect to the alpha-phosphorus of ATP is not identical for all aminoacyl-tRNA synthetases.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D007700:Kinetics; D008968:Molecular Conformation; D010649:Phenylalanine / Q000378:metabolism*; D010652:Phenylalanine-tRNA Ligase / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000378:metabolism; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D013873:Thionucleotides / Q000378:metabolism*; D046249:Transfer RNA Aminoacylation
chemical_list: D013873:Thionucleotides; D010649:Phenylalanine; D000255:Adenosine Triphosphate; D000604:Amino Acyl-tRNA Synthetases; D010652:Phenylalanine-tRNA Ligase