Biopolymers and cell. 2002; 18 (6): 547 - 550

Homology modeling of structure of NH2-terminal module of mammalian (Bos taurus) tyrosyl-tRNA synthetase

K. A. Odynets, O. E. Bazylevskyi, A. I. Kornelyuk

Mammalian tyrosyl-tRNA synthetase (TyrRS) is composed of two structural modules: the NHi-tenninal catalytic core and cytokine-like COOH-terminal module. In order to elucidate the structural bases for the N-module functions we have used the computational prediction of its three-dimensional (3D) structure by comparative modeling approach. A model of the bovine TyrRS N-module represents the Rossmann nucleotide-binding fold (RF) which is linked to the a-helical domain (aHD). The RF domain forms a single ji-sheet containing 5 parallel and one attached antiparallel fi-strands surrounded by a-helices. The connective polypeptide, CP1, inserted between fil- and f$4-strands of the RF domain is perturbed from the domain core. Comparative analysis of this multiple sequence alignment of known TyrRSs and the obtained model structure reveals the conservative surface elements, which could potentially form the tRNATyr-binding surface. This putative surface includes some exposed amino acid residues of CP1, e. g. essential LysJ46 and Lysl47 residues, which were identified earlier by site-directed mutagenesis.