result, and interestingly, it was evident that the antibacterial efficacy of the engineered enzymes was dominated by their Ivyc evasive properties, as opposed to their inherent Iytic capacities under noninhibitory conditions.
Given that ID and 1F had both inadvertently acquired greater susceptibility to the Ivyp homologue, we contemplated the possibility that they might also have greater sensitivity to MliC, an unrelated membrane-bound lysozyme inhibitor and known E. coli virulence factor.35,36 To test this hypothesis, we purified a soluble form of E. coli MliC and tested its inhibitory capacity in microplate kinetic assays (Figure 4B). For wild type hLYZ, MliC was significantly less potend than Ivyc (at 200 nM inhibitor, 86% vs 6% residual activity, respectively). Conversely, MliC and Ivyc manifested largely equivalent inhibition of 1D (60% vs 55% residual activity, respectively) and 2A (80% vs 87% residual activity, respectively). In a complete reversal of the wild type hLYZ trend, 1F was substantially more susceptible to MliC than Ivyc (33% vs 45% residual activity, respectively). Thus, as was found with Ivyp, the mutations selected