The receptor for colicin E3. Isolation and some properties.

A simple method for the isolation of the colicin E3 receptor is described. The receptor was extracted with lithium diiodesalicylate/urea/Triton X-100/EDTA from the cell envelope of Escherichia coli. The combination of affinity chromatography on immobilized protein A of colicin E3 with the efficient extraction led to the preparation of the receptor in a pure form, with a good yield (70%) and high activity. The purified receptor was a pure protein with a molecular weight of 60,000. The receptor protein was prepared in micelles of Triton X-100, and formed an equimolar complex with each E colicin (E1, E2, and E3), respectively. However, in the absence of the micelles, the receptor protein was easily inactivated.