Biophysical Society Conference | Tahoe 2022

Molecular Biophysics of Membranes

Poster Abstracts

23-POS Board 6 AN ENVIRONMENTALLY ULTRASENSITIVE MONOFLUOROETHYL NMR PROBE FOR MONITORING MULTI-CONFORMATIONAL EQUILIBRIA IN MEMBRANE PROTEIN Yun Huang 1,2 ; Krishna Reddy 3 ; Clay Bracken 3 ; Wenhu Zhang 4 ; David Eliezer 3 ; Olga Boudker 1,2 ; 1 Weill Cornell Medicine, Department of Physiology & Biophysics, New York, NY, USA 2 Howard Hughes Medical Institute, Chevy Chase, MD, USA 3 Weill Cornell Medicine, Department of Biochemistry, New York, NY, USA 4 Weill Cornell Medicine, Department of Microbiology & Immunology, New York, NY, USA Membrane proteins often undergo multiple conformational transitions to mediate solute transport or signal transduction. 19F NMR is an important tool for detecting and monitoring conformational transitions in membrane proteins. However, current 19F labels have a narrow chemical shift dispersion, limiting their ability to differentiate multiple conformations. Here, we report a new 19F NMR label which shows ultra-high sensitivity to conformational changes and achieves chemical shift dispersion reaching 9 ppm. Using the new probe, we show that at least 6 states comprise the conformational ensemble of a glutamate transporter homolog, GltPh. Guided by the 19F NMR spectra, we have used cryo-EM to determine the structures of these conformations and propose an ensemble description of the functional states of the transporter. This work demonstrated that combining the new 19F NMR and cryo-EM is powerful in studying the dynamic mechanisms of membrane proteins.

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