Purification of Bacteriophage λ, Int Protein

Abstract

BACTERIOPHAGE λ can direct the formation of small amounts of several λ proteins in a host whose endogenous protein synthesis has been decreased by ultraviolet irradiation before phage infection¹. The phage protein can be labelled by the incorporation of radioactive amino acids after infection. Many of these proteins can be resolved by sodium dodecyl sulphate (SDS) gel electrophoresis and tentative gene identifications can be made by comparing the products of wild type phage infection with those of phage carrying mutation(s) which selectively remove certain gene product(s)². I have purified the int gene product using differential label techniques to detect the Int polypeptide. This gene product functions in vivo to direct recombination between specific sites in DNA; the radiochemically pure product has been used to investigate the in vitro interaction between Int and DNA.