Expanding the biosynthetic mechanisms of natural antimicrobial peptides - Project Summary The recent interest in developing alternatives to traditional antibiotics are driving timely investments that are urgently needed to confront the growing antimicrobial resistance crisis. Fortuitously, the burgeoning microbial genomics era has revitalized efforts to explore natural products (NPs) as key sources of new antibiotics and their alternatives. However, tapping NPs as therapeutics requires a sophisticated understanding of biosynthetic mechanisms, the instructions of which are frequently encoded within discrete biosynthetic gene clusters (BGCs). Antimicrobial peptides (AMPs), a diverse class of NPs that are widely produced across evolution, are intensively being researched as an antibiotic alternative, especially because AMPs rapidly kill bacteria and that resistance to AMPs has been slow to emerge. Here, we aim to build upon the recent discovery of an AMP family, of which the corresponding BGC is unlike previously recognized BGCs for AMPs. Moreover, this AMP family and its BGC are widespread throughout diverse bacteria, which represents a rich resource of AMPs to exploit for future therapeutic development. Thus, to advance these efforts, the overarching goal of this project is to dissect the mechanisms of this novel BGC that leads to AMP production. Using a combination of molecular biology techniques, bacterial genetic approaches, and biochemical assays, we will focus on ascribing roles of the BGC components to 1) biosynthetic events that yield the mature AMP product and 2) the regulatory phenomena that may be needed to balance AMP yield against fitness costs to the producer. Our results will provide key knowledge that will serve as the basis for future sophisticated biochemical examinations, empower genome mining and bioengineering of this AMP class, advance future efforts that seek to optimize yields for cost-effective manufacturing of this AMP family in sufficient quantities for preclinical and clinical studies, and in designing strategies to prevent or subvert the rise of resistance to this AMP family.