Elucidating Physicochemical Features of Holin Proteins Responsible for Bacterial Cell Lysis

Bacterial resistance to conventional antibiotics stimulated the development of so-called "phage therapies" that rely on cell lysis, which is a process of destroying bacterial cells due to their infections by bacterial viruses. For λ bacteriophages, it is known that the critical role in this process is played by holin proteins that aggregate in cellular membranes before breaking them apart. While multiple experimental studies probed various aspects of cell lysis, the underlying molecular mechanisms remain not well understood. Here we investigate what physicochemical properties of holin proteins are the most relevant for these processes by employing statistical correlation analysis of cell lysis dynamics for different experimentally observed mutant species. Our findings reveal significant correlations between various physicochemical features and cell lysis dynamics. Notably, we uncover a strong inverse correlation between local hydrophobicity and cell lysis times, underscoring the crucial role of hydrophobic interactions in membrane disruption. Stimulated by these observations, a predictive model capable of explicitly estimating cell lysis times for any holin protein mutants based on their mean hydrophobicity values is developed. Our study not only provides important microscopic insights into cell lysis phenomena but also proposes specific routes to optimize medical and biotechnological applications of bacteriophages.