Independence of proline chemotaxis and transport in Bacillus subtilis

Values of KI for nine proline analogs as inhibitors of proline chemotaxis and of proline transport were determined. Two of them inhibited transport at substantially lower concentrations than chemotaxis; two at substantially higher concentrations. Moreover, mutants, believed to be in the component that binds proline, were isolated that showed a shift of KM for transport to higher concentrations, one as much as 40-fold. However, chemotaxis was virtually unaffected. Therefore, unlike galactose chemotaxis and transport in Escherichia coli, which share the galactose-binding protein, proline chemotaxis and transport in Bacillus subtilis are independent.