Crystal structure analyses of yeast tyrosyl-tRNA synthetase

Introduction Aminoacyl-tRNA synthetases (aaRSs) play a central role in the assembly of amino acids into polypeptide chains. By selection of the correct amino acid for acylation of a specific tRNA, they provide the key for translation of the genetic code. The 20 aaRSs are divided into two classes of 10 enzymes each. TyrosyltRNA synthetase (TyrRS) is a class I enzyme, but is unusual in that it is a functional dimer, a feature only shared with tryptophanyl-tRNA synthetase amongst class I aaRSs. Since there are differences of the tRNArecognition modes by TyrRSs between the eukaryotic/archaeal and prokaryotic systems, threedimensional structures of archaeal, eukaryotic, or prokaryotic TyrRSs complexed with their cognate tRNA have long been awaited. Recently, crystal structure analyses of prokaryotic and archaeal TyrRSs complexed with their cognate tRNA have been reported. On the other hand, crystal structure of eukaryotic (human) TyrRS lacking the C-terminal domain has been reported, however, no structures are available for eukaryotic TyrRS complexed with its cognate tRNA. To understand the structure-function relationships and the tRNA-recognition mode of eukaryotic TyrRS, we initiated the crystal structure analysis of yeast TyrRS (yTyrRS). Here we report the preliminary X-ray crystallographic studies of recombinant yTyrRS complexed with its cognate tRNA.