Analyses of Conditions for KMSSS Loop in Tyrosyl-tRNA Synthetase by Building a Mutant Library

概要

論文の詳細を見る
The KMSKS motif is the ATP binding motif for aminoacylation process of class I aminoacyl-tRNA sythetases. Various researches on the motif have been performed to reveal its catalytic properties. Most of the researches were based on motif searches and structural analyses from protein databases, and some interesting properties were discussed. Although researches based on natural proteins inform us about the contribution of natural amino acid sequences for the catalysis, they have difficulties in discussing the other alternative sequences and prohibited sequences for the motif to maintain the catalytic ability. In order to reveal such the conditions for the alternative and prohibited sequences, it is important to investigate a library of various mutants for the motif. Such the library should include inactive mutants as well as active mutants of the KMSKS motif, in order to discuss boundary conditions of active and inactive mutants. For that purpose, we build a library of more than two hundred mutants substituting the KMSSS loop, Lys204-Met205-Ser206-Ser207-Ser208, in tyrosyl-tRNA synthetase of Methanococcus jannaschii, and their degrees of catalytic were examined by the Amber suppression method. In this paper, activity degrees of all the mutants are represented in detail and some suggestion for the condition of the motif is discussed. [This abstract is not included in the PDF]