title: Proteinase sensitivity of bacteriophage lambda tail proteins gpJ and pH in complexes with the lambda receptor.
abstract: Previous studies have shown that bacteriophage lambda initially binds to liposomes bearing its receptor protein by the tip of the tail fiber (type 1 complex). It then associates more directly so that the hollow tail tube is in direct contact with the membrane (type 2 complex). DNA can be injected across the lipid bilayer into the liposome from type 2 complexes. We show here that gpJ, the tail fiber protein, becomes more sensitive to proteolytic degradation in type 2 complexes, indicating that the tail fiber does not pass into the liposome and that the tail fiber may undergo a conformational change in type 2 complexes. Another bacteriophage protein, pH, is sensitive to proteolytic degradation in free bacteriophage, type 1 complexes, or type 2 complexes formed with free receptor, but is resistant to proteinases in type 2 complexes formed with liposomes. This finding suggests that pH associates with the membrane. We suggest that this association is part of the mechanism by which a transmembrane hole for DNA entry is formed.
mesh_terms: D001425:Bacterial Outer Membrane Proteins; D010582:Bacteriophage lambda / Q000187:drug effects* / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases / Q000494:pharmacology*; D008081:Liposomes / Q000378:metabolism; D010455:Peptides / Q000145:classification; D018272:Porins; D011487:Protein Conformation / Q000187:drug effects; D011991:Receptors, Virus / Q000187:drug effects* / Q000378:metabolism; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D004279:DNA, Viral; D008081:Liposomes; D010455:Peptides; D018272:Porins; D011991:Receptors, Virus; D014764:Viral Proteins; C016532:maltoporins; D010450:Endopeptidases