Chemical Tools for Precision Metabolic Labeling and Detection of Terpenes and Prenylated Molecules

University Of Tennessee Knoxville, Knoxville TN

Investigators

Abstract

With the support of the Chemistry of Life Processes (CLP) Program in the Division of Chemistry, Joshua Baccile of the University of Tennessee is studying two biologically important classes of chemical entities, terpenes and prenylated molecules. They are among the largest classes of biomolecules and are both critical to basic life processes and clinically important as drugs. Terpenes and prenylated molecules both derive in part or in full, from the two structurally related five-carbon building blocks, isopentenyl pyrophosphate and dimethylallyl pyrophosphate (IPP and DMAPP, respectively). IPP and DMAPP are therefore among the most significant metabolic precursors in biology. Despite this prominence, chemical tools and strategies to study IPP and DMAPP in cells are lacking. Dr. Baccile aims to bridge this scientific gap through the development of a suite of IPP- and DMAPP-based chemical probes and methods for the metabolic labeling of terpenes and prenylated molecules and their detection in a cell-specific manner. The proposed tools and experiments will also enable a systematic evaluation of the roles of IPP and DMAPP themselves, which is not currently possible. In addition to the chemical innovation, Dr. Baccile will integrate objectives for innovation in student research mentorship, teaching, and learning through the introduction of new pedagogical training methods in the laboratory. Baccile will endeavor to broaden participation in chemistry through a dedicated summer program for underrepresented students in STEM (science, technology, engineering and mathematics) from community colleges. This research project sets out to investigate a facile and modular synthesis of IPP and DMAPP probes, which leverages a “prodrug”-like mechanism for precision metabolic labeling. While related strategies have been employed for metabolic labeling of glycans and proteins, this approach is innovative in natural product and post-translational modification (PTM) research. The proposed cell-type specific isotopic labeling and enrichment methods will enable detailed studies of the isoprenoid pathway in heterogenous cell populations, which could be transformative in our understanding of host-microbe interactions and tumor development. Currently, five-carbon prenyl PTMs are presumed to be absent in life in contrast to the well-established higher order protein prenylations known, specifically protein farnesylation (15 carbons) and geranylgeranylation (20 carbons). However, chemical probes engineered to definitively rule out such five-carbon modifications have not previously been tested. Successful application of the proposed probes will enable the potential identification of five-carbon prenyl modifications, which would be a paradigm shift in the field of protein prenylation. Significant regulatory mechanisms and signaling cascades could be mediated through this yet unknown PTM. We note that the proposed synthetic approach is modular and readily adapted to other pyrophosphate metabolites. This project is an important step toward the long-term goal of creating resources to study the biosynthesis, regulation, and function of biomolecules, with a focus on using isotopic labeling and enrichment chemistry to understand interkingdom signaling. 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.