DOMAINS OF ESCHERICHIA-COLI GLUTAMINYL-TRANSFER-RNA SYNTHETASE DISORDERED IN THE CRYSTAL-STRUCTURE ARE ESSENTIAL FOR FUNCTION OR STABILITY

Deletion analysis of E. coli glutaminyl-tRNA synthetase indicates that the N- and C-termini of the protein, which appear disordered in the c rystal 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-ty pe.