Biopolymers and cell. 1997; 13 (6): 474 - 478

Homology of C-terminal non-catalytic domain of mammalian tyrosyl-tRNA synthetase with cylokine EMAP II and non-catalytic domains of methionyl- and phenylalanyl-tRNA synthetases

0. V, Levanets, V. G, Naidenov, K. A, Odynets, M, I. Woodmaska, G. Kh. Matsuka, A. I. Kornelyuk

Mammalian tyrosyl-tRNA synthetase contains C-terminal domain which is dispensable for the enzyme catalytic activity in the. aminoacylation of homologous tRNA yr. Cloning and sequencing cDNA which encodes this mammalian tyrosyl-tRNA synthetase was performed by the 3'-RACE method. Comparison of the amino acid sequence of the C-terminal domain of this mammalian tyrosyl-tRNA synthetase with other proteins using program BLASTP has shown the highest homology level (62.7 % identity) with a new cytokine, EMAP II, inducible by chemical cancerogenesis and corresponding to the p43 protein from high molecular weight aaRS complex of mammalians and also with non-catalytic C-terminal domains of methionyl-tRNA synthetases from nematode (62.7 %) and bacteria (27.7 %) and with N-terminal domain of the fi-subunit of phe-nylalanyl-tRNA synthetase of E. coli (26.7 %). The hypothesis was proposed about possible forming of isolated C-domain as a result of the proteolytic digestion of tyrosyl-tRNA synthetase by intracellular proteases and about possible cytokinc-like activity of this C-domain.