Idiosyncratic helix-turn-helix motif in Methanosarcina barkeri seryl-tRNA synthetase has a critical architectural role.

ABSTRACT: All seryl-tRNA synthetases (SerRSs) are functional homodimers with a C-terminal active site domain typical for class II aminoacyl-tRNA synthetases and an N-terminal domain involved in tRNA binding. The recently solved three-dimensional structure of Methanosarcina barkeri SerRS revealed the idiosyncratic features of methanogenic-type SerRSs; that is, an active site zinc ion, a unique tRNA binding domain, and an insertion of approximately 30 residues in the catalytic domain, which adopt a helix-turn-helix (HTH) fold. Here, we present biochemical evidence for multiple roles of the HTH motif; it is important for dimerization of the enzyme, contributes to the overall stability, and is critical for the proper positioning of the tRNA binding domain relative to the catalytic domain. The changes in

SUBMITTER: Bilokapic S 

PROVIDER: S-EPMC2667757 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature