Molecular characterization of the beta-N-acetylglucosaminidase of Escherichia coli and its role in cell wall recycling

The beta-N-acetylglucosaminidase of Escherichia coli was found to have a no vel specificity and to be encoded by a gene (nagZ) that maps at 25.1 min. I t corresponds to an open reading frame, ycfO, whose predicted amino acid se quence is 57% identical to that of Vibrio furnissii ExoII. NagZ hydrolyzes the beta-1,4 glycosidic bond between N-acetylglucosamine and anhydro-N-acet ylmuramic acid in cell wall degradation products following their importatio n into the cell during the process for recycling cell wall muropeptides. Fr om amino acid sequence comparisons, the novel beta-N-acetylglucosaminidase appears to be conserved in all 12 gram-negative bacteria whose complete or partial genome sequence data are available.