Evidence that bacteriophage T4 eph1 is a missense hoc mutation

An electrophoretic mutation of bacteriophage T4, eph1, appears to code for a missense hoc (highly antigenic outer capsid) protein. This is based on the observation that particles lacking hoc protein (hoc- particles), after incubation in a crude extract of Escherichia coli infected with phage carrying the eph1 mutation acquired the electrophoretic mobility of the eph1 strain (the electrophoretic mobility of the eph1 strain itself is slower than that of hoc- particles). Thus, it is likely that during infection of E. coli with the eph1 strain, a hoc protein is made that has a lower negative charge than normal hoc protein but can nevertheless bind to particles lacking hoc protein. These results confirm that eph1 is a hoc mutation.