Association of the rIIA protein with the bacterial membrane.

Cell membrane proteins synthesized after infection of Escherichia coli B with wild-type phage T4 and rIIA mutants were analyzed by dodecyl sulfate-polyacrylamide gel electrophoresis. A protein with an approximate molecular weight of 74,000 is present in membranes isolated from T4r(+)-infected cells, but is not found in membranes prepared from cells infected with an rIIA mutant in which the major part of the rIIA cistron is deleted. In addition, infection of E. coli B with different rIIA amber mutants and deletions gives peptides, which are associated with the bacterial membrane, of molecular weights consistent with the location of the respective mutations in the cistron. The rIIA protein is synthesized with delayed early kinetics. The synthesis of the rIIB protein, which is also located in the membrane, is not affected by mutations in the A cistron; conversely, synthesis of the rIIA protein is not affected by mutations in the B cistron. A mutant (rII 1589) contains a deletion that originates in the A cistron and extends into the adjacent B cistron. This mutant directs the synthesis of a compound membrane protein consisting of the undeleted portions of the A and B cistrons. The synthesis of the compound protein appears to be under the control of the A promoter.