Protein-protein interactions in natural product biosynthesis

Project Summary. Natural products from non-ribosomal peptide synthetases, polyketide synthases, and their hybrid pathways serve as therapeutics for infectious diseases, immunosuppression, anti-inflammatory regulation, antifungal and antiparasitic applications. Given their complexity and robustness, these metabolic pathways are excellent starting points for molecular design and production, particularly given the promise of synthetic biology for biomanufacturing new molecular entities. However, we do not fully understand the mechanics and organization that regulates these multi-modular and multi-domain catalytic machines. Using both model systems and clinically relevant biosynthetic pathways, our team will explore the use of peptidyl carrier protein (PCP) crosslinking enabled through recently developed chemical biology methods. We will focus on elucidating structural information about protein-protein interactions between PCPs and ketosynthase, condensation, and thioesterase catalytic domains to elucidate the molecular mechanisms and structural requirements that guide biosynthesis. Using in silico molecular modeling, we will apply these findings toward the in vitro evolution of new PCP-enzyme arrangements capable of catalyzing the biosynthesis of novel molecules. Our team combines chemical biological probe development with NMR, X-ray crystallographic and single particle cryo-EM structural biology to develop a computationally tested understanding of the protein-protein interfaces and mechanisms that guide substrate processivity within carrier protein dependent biosynthesis.