FIG. 2.

Retention and elution of CheR and CheB in affinity columns carrying altered chemoreceptor pentapeptides. Cell extracts (E) containing methyltransferase (CheR) or methylesterase (CheB) were applied to affinity columns carrying the indicated peptide. Fractions were collected during application of the sample (F) in a column volume, with washing by three column volumes of buffer (B) and two column volumes of buffer containing the NWETF pentapeptide (P). Protein content of the same volume of each fraction was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and staining with Coomassie brilliant blue. Representative results for the two families of altered peptides are shown in panels A and B, respectively.