Tryptophanyl-tRNA Synthetase (TrpS) is involved in protein synthesis and regulation of
RNA transcription and translation. It catalyzes a two-step reaction, first charging a tryptophan molecule by linking its
carboxyl group to the alpha-phosphate of ATP, followed by transfer of
the aminoacyl-adenylate to its tRNA. The structure was produced by co-crystallizing
the protein with ADP, however, not only ADP but also Trp were found bound tightly in the active site located in the middle of each subunit of the dimer.