Second‐site reversion of a structural defect in bacteriophage T4 lysozyme

A plasmid‐borne gene encoding bacteriophage T4 lysozyme with a structural mutation, Tyr 161 ‐Ala, was mutagenized by the use of polymerase chain reaction. The mutagenized gene was inserted into a specialized bacteriophage λ cloning vector that must acquire a functional lysozyme gene in order to form plaques. Functional variants of the mutant lysozyme were selected. Three compensatory second‐site revertants were obtained: Thr 152 ‐Met, Lys 43 ‐De, and Thr 151 ‐Ala. The effects of these mutations are interpreted in light of previous structural and genetic studies of T4 lysozyme.—Bouvier, S. E., Poteete, A. R. Second‐site reversion of a structural defect in bacteriophage T4 lysozyme. FASEB J. 10, 159‐163 (1996)