Hen egg white lysozyme (HEWL) has recently been reported to be able to catalyze polymerization reactions of small molecules like 2-ethynylpryimidne (2-EP) without needing organic solvents or toxic transitional metals. This chemistry is quite different from its natural muramidase activity. T4 lysozyme (T4L) is a bacteriophage lysozyme that functionally rivals HEWL in its enzymatic abilities but has a different sequence but structurally similar active site with two key acidic residues. A D20A mutation of one of these key residues resulted in a partial reduction in muramidase activity, consistent with others results. Interestingly this loss of a carboxylate also eliminated catalytic activity for the polymerization reaction of 2-EP, which was determined by a UV-vis assay over the course of 11 days. The D20A mutated protein was purified identically as the T4L wild type protein, which has been successful in both catalysis of polymerization and lysis. This observation suggests that not only is D20 an important catalytic site necessary for polymerization but it proves that T4L is responsible for the 2-EP reactions. Additional mutations are planned to try to further probe the mechanism of 2EP polymerization as has previously been done for muramidase activity. By obtaining a thorough understanding of the active site requirements in T4L it may be possible to predict new substrates and hence generate new conjugated polymer materials.

Alteration in enzymatic activity due to a mutation in bacteriophage lysozyme

2019 Spring National Meeting

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