In enzymology, a phenylalanine—tRNA ligase () is an enzyme that catalyzes the chemical reaction
ATP + L-phenylalanine + tRNAPhe AMP + diphosphate + L-phenylalanyl-tRNAPhe
The 3 substrates of this enzyme are ATP, L-phenylalanine, and tRNAPhe, whereas its 3 products are AMP, diphosphate, and L-phenylalanyl-tRNAPhe.
This enzyme belongs to the family of ligases, to be specific those forming carbon-oxygen bonds in aminoacyl-tRNA and related compounds. The systematic name of this enzyme class is L-phenylalanine:tRNAPhe ligase (AMP-forming). Other names in common use include phenylalanyl-tRNA synthetase, phenylalanyl-transfer ribonucleate synthetase, phenylalanine-tRNA synthetase, phenylalanyl-transfer RNA synthetase, phenylalanyl-tRNA ligase, phenylalanyl-transfer RNA ligase, L-phenylalanyl-tRNA synthetase, and phenylalanine translase. This enzyme participates in phenylalanine, tyrosine and tryptophan biosynthesis and aminoacyl-tRNA biosynthesis.
Phenylalanine-tRNA synthetase (PheRS) is known to be among the most complex enzymes of the aaRS (Aminoacyl-tRNA synthetase) family. Bacterial and mitochondrial PheRSs share a ferredoxin-fold anticodon binding (FDX-ACB) domain, which represents a canonical double split alpha+beta motif having no insertions. The FDX-ACB domain displays a typical RNA recognition fold (RRM) formed by the four-stranded antiparallel beta sheet, with two helices packed against it.
Structural studies
As of late 2007, 10 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , and .