Speaker
Description
In this talk I will first present our recent development of multiple 19F-based solid-state NMR techniques that increase the distance reach of NMR to ~2 nm. 19F-19F distances can be measured by both spin diffusion and dipolar recoupling techniques under fast MAS frequencies of 25 – 55 kHz at the medium-high magnetic field of 14.1 Tesla. Fast MAS suppresses the 19F chemical shift anisotropy sidebands without compromising the dipolar coupling measurements. An empirically calibrated master curve has been obtained from 19F-19F spin diffusion buildup rates to allow extraction of semi-quantitative distances. We also demonstrate 13C-19F and 1H-19F distance measurements under fast MAS. These long-distance 19F SSNMR techniques are instrumental for determining the cholesterol-binding site of the influenza M2 protein, the oligomeric structure of the HIV fusion protein gp41, and the interhelical packing of the influenza B virus M2 protein. In the second part of the talk, I will describe the determination of a novel amyloid fibril structure formed by the anti-hypoglycemia pharmaceutical peptide, glucagon.