Bacillus subtilis CheD is a chemoreceptor modification enzyme required for chemotaxis

The chemotaxis machinery of Bacillus subtilis is sim-ilar to that of the well characterized system of Esche-richia coli. However, B. subtilis contains several chemo-taxis genes not found in the E. coli genome, such as cheC and cheD, indicating that the B. subtilis chemotactic system is more complex. In B. subtilis, CheD is required for chemotaxis; the cheD mutant displays a tumbly phe-notype, has abnormally methylated chemoreceptors, and responds poorly to most chemical stimuli. Homologs of B. subtilis CheD have been found in chemotaxis-like operons of a large number of bacteria and archaea, sug-gesting that CheD plays an important role in chemotac-tic sensory transduction for many organisms. However, the molecular function of CheD has remained unknown. In this study, we show that CheD catalyzes amide hy