Solid-State NMR Spectroscopy
NMR is one of the few techniques that can characterize molecules at an atomic level, and is therefore ideally suited to answer many detailed questions about protein structure and function. We use magic-angle spinning NMR to investigate samples that are intrinsically in a solid or semi-solid state such as large protein complexes, amyloid fibrils, and membrane proteins embedded in lipid bilayers. Recently, an increase in the spinning frequency to 111 kHz was shown to optimize sensitivity and resolution for fully protonated samples by detection of proton resonances. Several synergies, including the straightforward detection of side-chain protons, and a multitude of proton-proton distances is transforming the technique into a more versatile and general approach for protein structure determination (see the aliphatic proton spectra shown in the figure for a microcrystalline protein, a capsid protein, a fibril, and a membrane protein). The MPI is a premier institution for magnetic resonance, and in the Solid-State group, we have dedicated instruments at 850 MHz, 800 MHz, 600 MHz with DNP, and 400 MHz, as well as time on a shared 950 MHz instrument.