Synthesis of phage M13 coat protein and its assembly into membranes in vitro.

Abstract

The coat protein (gene 8 product) of coliphage M13 is an integral protein of the host cell [Escherichia coli] membrane at all stages of virus infection. This protein, when made in a cell-free reaction, was shown by others to have an additional NH2-terminal peptide region and is referred to as procoat. It is initially not membrane-bound but, upon exposure to E. coli membrane vesicles or to liposomes prepared from E. coli lipids, it assembles into the bilayer in an integral fashion. Much of this protein is exposed on the inner surface of the liposome. Refolding of procoat as it encounters the bilayer is probably sufficient to transport large segments of the peptide chain through the apolar hydrocarbon core.