Domains of E. Coli Glutaminyl-tRNA Synthetase Disordered in the Crystal Structure Are Essential for Function or Stability

Abstract

Deletion analysis of E. coli glutaminyl-tRNA synthetase indicates that the N- and C-termini of the protein, which appear disordered in the crystal structure, are essential for function and stability in vivo. In vitro aminoacylation kinetics of a C-terminal deletion mutant exhibit a sharp reduction in the specificity constant. However, an N-terminal extension is catalytically, if not structurally equivalent to wild-type.