EUROISMAR 2019

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.