Translational and post-translational cleavage of M13 procoat protein: extracts of both the cytoplasmic and outer membranes of Escherichia coli contain leader peptidase activity.

Abstract

The coat protein of coliphage M13 is an integral protein of the host cytoplasmic membrane at all stages of the infectious cycle. Both in in vivo and DNA-directed in vitro synthesis, it is initially made with an NH2-terminal leader peptide of 23 amino acids and is termed procoat. Leader peptidase, an activity which removes the leader peptide and converts procoat to coat, is found in the inner (cytoplasmic) and outer membrane of E. coli. Only cytoplasmic membranes will catalyze cleavage of procoat without detergent. Leader peptidase will cleave procoat during translation or after protein synthesis is complete.