Compensation for D-glutamate auxotrophy of Escherichia coli WM335 by D-amino acid aminotransferase gene and regulation of murI expression.

D-glutamate, an indispensable component of peptidoglycans of bacteria, is provided by glutamate racemase in E. coli cells. Compensation for D-glutamate auxotrophy of E. coli WM335 cells lacking the glutamate racemase gene, murI, with the D-amino acid aminotransferase gene suggests that presence of a threshold concentration for the D-glutamate required by E. coli cells, as well as a regulation system for murI expression.