Multiple methylation in processing of sensory signals during bacterial chemotaxis

The multiple banding pattern on NaDodSO4/polyacrylamide electrophoresis of a subset of the signal transduction proteins involved in bacterial chemotaxis has been shown to be caused by multiple methylation of a single gene product. At least four methyl groups are introduced per molecule of the sensing membrane protein to give a total of five bands. The separation of the bands appears to correspond to a Mr difference of 1500, probably caused by the binding of different amounts of DodSO4 molecules as carboxyl groups are modified. Multiple methylation, similar to multiple phosphorylation in other systems, appears to offer advantages in control and sensory processing.