Siddharth Premnath

Once a miracle cure, antibiotics now face resistance from their targets, forming the basis of one of the most significant problems of the 21st century. In addition to the emergence of multiresistant bacteria, there is a shortage of antibiotics due to the high cost and risk associated with their development. Antimicrobial peptides (AMPs) could offer an alternative to traditional small-molecule antibiotics. Bacteriocins, a subgroup of AMPs, are small, bacterially-produced peptides with highly specific activity against several targets. As a result of this high specificity, they are less disruptive to the native microbiota than conventional antibiotics and will likely minimize negative off-target effects. Developing new, potent molecules as therapies was the main goal of this project. Site-saturation mutagenesis is a commonly used method to create a gene library containing all possible single mutations in a gene sequence, and this technique was implemented to engineer enterocin B, a relatively unexplored, heat-stable bacteriocin with a broad spectrum of inhibition. An active enterocin B variant with inhibitory activity against Enterococci was developed, thus contributing to the search for the next the generation of antimicrobial therapies. Looking ahead, a library of enterocin B variants could be developed, thereby broadening our understanding of the sequence-activity relationship for these peptides. Additionally, these variants could be tested for activity against a broader array of bacterial strains to determine specificity.