The Brown Center invites you to our Faculty Spotlight on Friday, October 29th at 2:00 PM on Zoom. The spotlight series is a showcase of research, creative inquiry, and other scholarly engagement of the campus community. Stop by and learn about the research of our talented Stetson community!
Dr. Matthew Shannon – Assistant Professor of Biochemistry
Department of Chemistry
Development of Methods to Extract Long Distances in Proteins using Nuclear Magnetic Spectroscopy (NMR)
Structure determination of proteins, or folded polymers of amino acids, is a crucial step to understand their function. Many spectroscopic methods besides NMR currently exist to determine the structures of proteins such as X-ray crystallography and cryo-EM; however, these methods subject samples to conditions that are not representative of their native, physiological aqueous state. In NMR, samples are studied in vitro at temperature, pH, and concentrations that tend to mimic in vivo conditions. To determine the structures of proteins using NMR, short distances (< 0.5 nm) can be determined by measuring Nuclear Overhauser Effects (NOEs) and dipolar couplings between atomic nuclei (e.g., 1H, 13C, and 15N are the NMR active nuclei that comprise over 99% of the atoms in proteins). To unambiguously determine the structures and interactions of proteins more precisely and accurately, it is advantageous to have novel methods to measure longer distances (> 1 nm). Herein, we show that imidazole, the sidechain of the amino acid histidine, can chelate to paramagnetic metal ions (e.g., Cu2+, Mn2+, and Co2+). These paramagnetic ions can either cause NMR signals to broaden (Cu2+ and Mn2+) or shift (Co2+). The extent of peak broadening (i.e., paramagnetic relaxation enhancements) or peak shifting (i.e., pseudocontact shifts) can be used to calculate accurate, precise long distances on the nm scale.
Matthew Shannon (Ph.D., The Ohio State University) is an Assistant Professor in the Department of Chemistry and Biochemistry. As a biophysical chemist by training, his interdisciplinary research interests focus on the use of spectroscopic methods to probe the structure, dynamics, and interactions of macromolecules in solution. He specializes in the application of novel NMR methods to probe atomic level information of proteins that are important for their biological function.