RUI: Biochemical Comparison of Type II Polyketide Biosynthetic Enzymes Across Phyla for Expanded Access to Chemical Diversity

Haverford College, Haverford PA

Investigators

Abstract

With the support of the Chemistry of Life Processes Program in the Division of Chemistry, Dr. Louise Charkoudian and her team from Haverford College will investigate how assemblies of bacterial proteins can be leveraged to synthesize molecules that benefit society. Bacteria have evolved the ability to express protein assemblies that catalyze the manufacture of very complicated molecules. If understood at the molecular level, these protein assemblies hold tremendous potential to provide sustainable access to important chemical commodities. This project will engage undergraduate students in the study of the evolution of these assemblies, in identifying the features that confer function and stability upon these assemblies, and in the engineering of new assemblies that have the potential to catalyze the synthesis of novel molecules. The research will provide information about protein assemblies that have never been studied in the laboratory. Tools to facilitate future discovery and engineering efforts will also be developed. The undergraduate students engaged in this research will gain scientific knowledge and learn research skills. They will also learn how to develop professional networks and about different institutions and career paths in a “Symbiotic Professional Development Seminar Series”. This series will also be open to graduate students from research universities. To spark scientific appreciation and foster engagement of the community in discussions of scientific topics, Dr. Charkoudian will develop a “BioArt Greeting Cards” project in which photographs of student-made pieces of biological art are turned into greeting cards. Type II polyketide synthases (PKSs) are powerful biocatalysts in reactions that produce structurally complex and diverse molecules. Progress towards reconstituting type II PKSs in vitro has been stymied by the lack of a robust heterologous expression system for obtaining key type II PKS components. In this project, bioinformatics will be used to create an updated catalogue of type II PKS biosynthetic gene clusters and to identify those ripe for characterization based on phylogeny of origin, inferred evolutionary history, and other sequence patterns. Non-actinomycete bacterial species will be evaluated as a source of type II PKS enzymes that can be expressed in E. coli as stable, active proteins. Specifically, ketosynthase chain length factors (KSCLFs), acyl carrier proteins (ACPs) and phosphopantetheinyl transferases (PPTases) will be characterized to determine the features that influence their stability and function. The compatibility of type II PKS ACPs with PPTases across different PKSs will be explored. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.