UC San Diego

Solid-state nuclear magnetic resonance (NMR) spectroscopy is a robust method to solve the structures of membrane proteins in their native bilayer environments. Two systems have been well established: oriented samples (OS) are referred to proteins incorporated in the magnetic aligned bicelles, and rotationally aligned (RA) samples are referred to proteins undergoing fast rotational diffusion in proteoliposomes. 1H-15N and 1H-13C dipolar couplings are measured as the angular restraints for the structure calculations. New separated-local-field experiment, Dual- PISEMO, is developed for OS solid-state NMR to measure 1H- 13C dipolar couplings of the uniformly 13C labeled proteins, which provide both backbone and side-chain conformations. In order to obtain the full assignments and restraints in OS solid-state NMR, 1H-irradiations with mismatched conditions are implemented to improve the crucial step: the magnetization transfer between 15N and 13C. Non-uniform sampling (NUS) is an alternative approach to further the experimental time of high-dimensional solid -state NMR experiments. Compressed sensing (CS) is able to reconstruct the spectra with 25 ̃ 33% of data with the optimized sampling scheme, and covariance spectroscopy provides promising results with alternative States sampling scheme, which requires 50% of data or less. Viral protein "u" (Vpu) from HIV-1 is a type I membrane protein consisting of a transmembrane domain and a cytoplasmic domain, which are associated with different biological activities to enhance viral infectivity. It is essential to determine the three-dimensional structure of Vpu in order to understand its mechanisms in the molecular level and to develop new classes of anti-viral drugs. Magic- angle spinning (MAS) experiments providing high- sensitivity and high- resolution spectra, are implemented to study Vpu incorporated into proteoliposomes. 15N, 13C chemical shift and 1H-15N, 1H-13C dipolar couplings are measured and converted to equivalent structural restraints