Conformational flexibility of cytokine-like C-module of tyrosyl-tRNA synthetase monitored by Trp144 intrinsic fluorescence.
The non-catalytic COOH-terminal module formed after proteolytic cleavage of full-length mammalian tyrosyl-tRNA synthetase displays dual function: tRNA binding ability and cytokine activity. With the aim to explore the intramolecular dynamics of C-module in solution we used fluorescence spectroscopy to study conformational changes of isolated protein. We used information from fluorescence spectra and computational model for characterization of a microenvironment of a single tryptophan residue (Trp144). Its fluorescence parameters and protection from quenching by Cs+ ions indicate the internal localization--buried into protein globule. The fluorescence quenching of Trp144 by acrylamide suggests rapid conformation dynamics of the C-module in nanosecond time scale. The temperature-induced conformational changes in the C-module were monitored by the fluorescence measurements of Trp144 emission and by red-edge excitation shift. An emission maximum shift up to approximately 349 nm and significant decrease of the red-edge shift effect at 37-52 degrees C indicated a major conformational transition of Trp144 from buried native state into highly relaxing polar solvent environment.
Kordysh
Mariya
M
Department of Protein Engineering, Institute of Molecular Biology and Genetics, National Academy of Science of Ukraine, 150, Acad. Zabolotnogo Str., Kiev, Kyiv 03143, Ukraine. kordyshm@yahoo.com
Kornelyuk
Alexander
A
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D016207:Cytokines / Q000737:chemistry; D066298:In Vitro Techniques; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D013050:Spectrometry, Fluorescence; D013816:Thermodynamics; D014364:Tryptophan / Q000737:chemistry; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics
D016207:Cytokines; D011994:Recombinant Proteins; D014364:Tryptophan; D014448:Tyrosine-tRNA Ligase