Biopolymers and cell. 2009; 25 (1): 39 - 42

Study on the putative active site of Enterococcus faecalis prolyl- tRNA synthetase editing domain by methods of site-directed mutagenesis

K. S. Boyarshin, I. A. Kriklivyi, A. V. Rayevsky, A. A. Himin, A. D. Yaremchuk, M. A. Tukalo

Institute of molecular biology and genetics NAS of Ukraine 150, Zabolotnogo Str,  Kyiv  Ukraine, 03680

The maintenance of amino acid specificity by aminoacyl-tRNA synthetases can require the hydrolysis of missynthesized products that is known as amino acid editing. Bacterial prolyl-tRNA synthetase includes a special editing domain, that deacylates alanyl-tRNA^Pro, and so exhibits post-transfer editing activity. The mechanism of tRNA-dependent editing by prolyl-tRNA synthetase has to be defined. The present work aim is to study the structure of the active site of enterobacteria E. faecalis prolyl-tRNA synthetase editing domain. The amino acids positions E218, T257, K279, G331, S332, G334, and H366 have been chosen for the site-directed mutagenesis (alanine scanning). An editing activity of the mutants was compared with the wild type prolyl-tRNA synthetase. Three amino acid residues, important for the editing activity, K279, G331 and H366, were revealed. This data are consistent with the existing suppositions about the structure of bacterial prolyl-tRNA synthetase deacylating active site.

Keywords: prolyl-tRNA synthetase, editing, tRNA, site-directed mutagenesis.