The Head-Tail Linker Protein of Bacteriophage T5: Genetic and Immunological Studies

We investigated the properties of amber mutants of coliphage T5 defective in a late stage of phage assembly. The non-functional heads synthesized by mutants am25 or am158 were unable to combine with functional tails to produce viable phage particles. These mutants were shown to lack a single protein, designated the head-tail linker protein (HTLp), which was identified by polyacrylamide gel electrophoresis and Western blot analysis and had an M r of 18000. An extract containing the HTLp, when added to the HTLp-deficient heads, restored their ability to combine with functional tails.