Structure of phage P22 gene 19 lysozyme inferred from its homology with phage T4 lysozyme. Implications for lysozyme evolution.

The amino acid sequence of the lysozyme from phage P22 is shown to be homologous (26% identity) with the lysozyme from bacteriophage T4. The sequence correspondence suggests that the structure of P22 lysozyme is similar to the known structure of T4 lysozyme within the "core" of the molecule, including the active site cleft. However, P22 lysozyme appears to lack two surface loops present in T4 lysozyme. It is possible that P22 lysozyme may provide an "evolutionary link" between the phage-type lysozymes and the goose-type lysozymes.