A Chinese hamster ovary leucyl-tRNA synthetase mutant with a uniquely altered high molecular weight leucyl-tRNA synthetase complex.
The Chinese hamster ovary (CHO) cell culture temperature-sensitive mutant ts025Cl with a defect in leucyl-tRNA synthetase ( LeuRS ) does not have an inherently more thermolabile LeuRS , but instead the mutation causes the complete loss of the LeuRS high molecular weight complexes which are present in normal wild-type cells. The mutant cell LeuRS has a single 8 S enzyme form which corresponds hydrodynamically to the 8 S free form of wild-type enzyme. Both 8 S forms have the same thermostability and the same Km for leucine, indicating that there is no inherent defect in the catalytic activity of the enzyme. The temperature-sensitive phenotype can be explained by the lack of thermostable high molecular weight forms of LeuRS .
D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D007935:Leucine-tRNA Ligase / Q000235:genetics*; D008970:Molecular Weight; D009154:Mutation; D010053:Ovary / Q000201:enzymology; D013696:Temperature
D000604:Amino Acyl-tRNA Synthetases; D007935:Leucine-tRNA Ligase