CAREER: Reprogramming Polyketide Biosynthesis

North Carolina State University, Raleigh NC

Investigators

Abstract

The Chemistry of Life Sciences Program funds Professor Gavin Williams of North Carolina State University for a CAREER award to carry research entitled "Reprogramming Polyketide Biosynthesis." Polyketide synthases (PKSs) are giant enzyme assemblies that construct a large array of natural products called polyketides. In general, polyketide structure is determined by the identity and sequence of modules in the PKS, and this feature offers the prospect of creating designer PKSs for the synthesis of polyketide analogues. However, our poor understanding of the relationship between protein sequence, structure and function, limits the extent to which PKSs can be manipulated. The development and application of tools at the interface of chemistry and biology is likely required to overcome engineering obstacles and contribute to our understanding of PKS chemistry. This work will employ key techniques in chemical biology to probe, interrogate, and manipulate the chemistry of PKSs in vitro. The project aims to 1) overcome strict PKS substrate specificity by using directed molecular evolution to create a chemo-enzymatic pathway constructed from discrete, "stand-alone" enzymes, 2) explore the use of non-natural prosthetic arms to alter substrate specificity, promiscuity, and catalysis of PKSs, and 3) map critical protein interaction interfaces, with single residue resolution, using a novel photocrosslinking assay. The design principles gathered from this research will reveal how PKSs and related enzymes catalyze the construction of complex products from simple building blocks. The researchers will explore the limitations with which PKSs can be manipulated by chemical biology, and fully delineate the synthetic capabilities of biosynthetic machinery. The broader impacts resulting from teacher-scholar activities which are integrated with the research plan includes invigorating youth to become the next generation of scientists, demonstrating enzyme chemistry and its importance, and emphasizing the role of chemistry in society. Proposed activities include: 1) the creation of an "enzyme workstation" that integrates underlying concepts in the NC K-12 program; 2) broaden participation of underrepresented minorities by co-leading the NSF REU Chemistry site at NCSU and mentoring future NC Project SEED; 3) design and implementation of an undergraduate laboratory module and graduate class aimed at unifying concepts in chemistry and biology; and 4) involvement of the broader community by participation in Science Café.