| Abstract: | By means of small angle X-ray scattering, an aggregation of beef pancreas Trp-tRNA synthetase (EC 6.1.1.2) was observed at physiological temperatures. A Trp-tRNA synthetase preparation which is homogeneous after PAGE in beta-ME-SDS was found to be heterogeneous in particle sizes even at low (4-8 degrees C) temperature. At heating up to 30-45 degrees C, the oligomer sizes increased as well as its proportion depending on the incubation time and temperature; very large aggregates were observed 10 times exceeding the sizes of initial particles. Cooling to 20 degrees C caused no disaggregation due to disulphide bond formation between associated subunits of Trp-tRNA synthetase. A hypothesis is proposed that the aggregation of bovine Trp-tRNA synthetase evaluated in vitro and not observed earlier with any aminoacyl-tRNA synthetases of unicellular organisms might serve as one of the mechanisms of its compartmentation in pancreas. |
