Phenylalanyl-tRNA synthetase (PheRS) alpha chain catalytic core domain. PheRS belongs to class II aminoacyl-tRNA synthetases (aaRS) based upon its structure and the presence of three characteristic sequence motifs. This domain is primarily responsible for ATP-dependent formation of the enzyme bound aminoacyl-adenylate. While class II aaRSs generally aminoacylate the 3'-OH ribose of the appropriate tRNA, PheRS is an exception in that it attaches the amino acid at the 2'-OH group, like class I aaRSs. PheRS is an alpha-2/ beta-2 tetramer.