Alterations of receptor specificities of coliphages of the T2 family.

The T-even type coliphage M1 uses the outer membrane protein OmpA as a receptor. Host range mutants were isolated in two sequential steps, the first resulting in strains able to use the porin OmpC, the second in mutants using the outer membrane protease OmpT as receptor. The mutational alterations in the receptor-recognizing protein of the phage (a component of the long tail fibers) have been determined. Their character and that of such previously described alterations suggest an antibody-type of ligand binding.