Methyl-accepting chemotaxis proteins are distributed in the membrane independently from basal ends of bacterial flagella.

Chemotactic behavior of Escherichia coli involves communication between methyl-accepting chemotaxis proteins and basal ends, the rotary motors of bacterial flagella. Both the proteins and the basal ends are embedded in the cytoplasmic membrane, but the spatial relationship between the two has not been determined. This communication describes a procedure for obtaining a preparation of membrane vesicles enriched in basal ends and thus in the regions of membrane immediately surrounding them. Methyl-accepting chemotaxis proteins were neither enriched nor depleted in this membrane fraction but instead were distributed throughout the membrane. Thus functional linkages between these proteins and flagellar motors must be mediated by processes other than direct physical interaction.