FACULTY & STAFF
Gregory P. Tochtrop
Assistant Professor of Chemistry
tochtrop@case.edu
Office Phone: 368-2351
Synthetic Organic Chemistry and Biochemistry
B.S., University of Missouri, 1996
Ph.D., Washington University School of Medicine, 2002
NIH Postdoctoral Fellow, Harvard University, 2002-2006
At the heart of many if not most biological events is the inherently chemical process of a small molecule being recognized by a large biological polymer. Research projects in the lab will be designed to push back the boundaries of the tools used to monitor protein small molecule interactions. This work spans from pure synthetic organic chemistry to quantitative biochemistry. The three projects which will start the lab are outlined below.
Chemical Interrogation of FXR Function
The pool of bile acids present in the human body at any one time is chemically heterogeneous consisting of at least 100 distinct members. One of the major interactions responsible for bile acid homeostasis (and consequently cholesterol homeostasis) is their recognition by the nuclear receptor FXR. The proposed experimental approach is to synthesize 13C and 15N isotopically enriched bile acids and monitor recognition, segregation, and competition using NMR. Using this approach we will be able to monitor single bile acids in complex mixtures and understand their effects on the transcription of FXR gene products.
Diversity Oriented Synthesis
We anticipate building the concept of generating skeletal diversity through chemistries that 'reorganize' the carbon skeletons of compelx natural products into novel molecules. The clevage of the B-C unsaturated ring fusion of lanosterol is a prime example of this strategy. Here, oxidative cleavage of the unsaturated ring fusion followed by transannular addition or full condensation affords diverse skeletons depending partly on the oxidation state of carbons C-7 and C-11. These molecules will be used to probe biological systems using a 'chemical genetic' approach.
A Proteome Wide Binding Assay
Small molecule microarray technology entails the covalent coupling of small molecules to a glass surface. Traditionally, this surface is then probed with a fluorescently labeled protein to identify binding interactions. The goal of this project is to take small collections of molecules (Ideally from diversity oriented libraries from the lab) and print them repetitively in the format of a 96-well plate (to facilitate the screening of multiple proteins). These 100 molecules will then be screened against the entire yeast proteome (approximately 4000 proteins) for potential binding interactions.
Selected Publications
- Rati Verma, Noel R. Peters, Mariapina D'Onofrio, Gregory P. Tochtrop, Kathleen M. Sakamoto, Ranjani Varadan, David Fushman, Raymond J. Deshaies, and Randall W. King "Inhibition of Proteasome-Dependent Degradation by a Small Molecule that Binds the Ubiquitin Chain", Science 306, 117-120 (2004)
- Gregory P. Tochtrop, Gregory T. Dekoster, Douglas F. Covey, and David P. Cistola "Ligand Site Specificity in Human Ileal Bile Acid Binding Protein" JACS 126, 11024-11029 (2004)
- Gregory P. Tochtrop, Jamie L. Bruns, Changguo Tang, Douglas F. Covey, and David P. Cistola "Calorimetric Analysis of Bile Salt Binding to Human Ileal Bile Acid Binding Protein" Biochemistry 42, 11561-11567 (2003)
- Gregory P. Tochtrop, Gregory T. DeKoster, David P. Cistola, and Douglas F. Covey "Synthesis of [3,4-13C2]-Enriched Bile Salts As NMR Probes of Protein-Ligand Interactions" J. Org. Chem. 67, 6764-6771 (2002)
- Gregory P. Tochtrop, Klaus Richter, Changguo Tang, James J. Toner, Douglas F. Covey, and David P. Cistola, "Energetics by NMR: Site-Specific Binding in a Positively Cooperative System," PNAS 99, 1847-1852 (2002)