Phosphotransferase-system enzymes as chemoreceptors for certain sugars in Escherichia coli chemotaxis.

For D-glucose and analogs there are two distinct phosphotransferase enzymes II with different specificities. Transport and chemotaxis were studied in E. coli mutants having only one or the other of these two enzymes. It was found that the transport specificity of a given enzyme II correlates with taxis specificity, and mutational loss of an enzyme II abolishes taxis toward only those sugars which it alone transports. Although enzyme I and the phosphate-carrier protein are required for full D-glucose taxis, it could not be determined if phosphorylation and transport are also required.