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.

Grant Number: 5R01GM095970-14
NIH Institute/Center: NIH
Principal Investigator: Michael Burkart