Biopolymers and cell. 2007; 23 (2): 130 - 136

Conformational Mobility Investigation of TyrRS С-module and Its Complex with tRNA using the Methods of Time-Resolved Fluorescence Spectroscopy

M. O. Kordysh, G. V. Kyryushko, Y. Mely, O. I. Kornelyuk

The non-catalytic C-module formed after proteolytic cleavage of full-length mammalian tyrosyl-tRNA synthetase displays RNA-binding ability. C-module contains a unique tryptophan residue (Trp144), located out of its RNA-binding site, and a conservative aromatic residue Phe127 located inside of its RNA-binding site, which was replaced by fluorophore Trp127. Obtained fluorescence decay parameters of free C-module Trp144 and its complex with tRNA detect the absence of tRNA-interaction sensitivity. Obtained fluorescence decay parameters of Trp144 and Trp127 of C-module and its complex with tRNA are characterized by the additional short-lived component without any sufficient changing of other fluorescence parameters in the presence of nucleic acid. It indicates the existence of the polymorphism of Trp127 microsurrounding that is conditioned by the dynamic protein–nucleic acid interaction mechanism.

Keywords: tyrosyl-tRNA synthetase C-module, time-resolved fluorescence spectroscopy, conformational mobility.