Expanding the horizons for structural analysis of fully protonated protein assemblies by NMR spectroscopy at MAS frequencies above 100*kHz
Publication date: Available online 3 July 2017
Source:Solid State Nuclear Magnetic Resonance
Author(s): Jochem Struppe, Caitlin M. Quinn, Manman Lu, Mingzhang Wang, Guangjin Hou, Xingyu Lu, Jodi Kraus, Loren B. Andreas, Jan Stanek, Daniela Lalli, Anne Lesage, Guido Pintacuda, Werner Maas, Angela M. Gronenborn, Tatyana Polenova
The recent breakthroughs in NMR probe technologies resulted in the development of MAS NMR probes with rotation frequencies exceeding 100*kHz. Herein, we explore dramatic increases in sensitivity and resolution observed at MAS frequencies of 110–111*kHz in a novel 0.7*mm HCND probe that enable structural analysis of fully protonated biological systems. Proton- detected 2D and 3D correlation spectroscopy under such conditions requires only 0.1–0.5*mg of sample and a fraction of time compared to conventional 13C-detected experiments. We discuss the performance of several proton- and heteronuclear- (13C-,15N-) based correlation experiments in terms of sensitivity and resolution, using a model microcrystalline fMLF tripeptide. We demonstrate the applications of ultrafast MAS to a large, fully protonated protein assembly of the 231-residue HIV-1 CA capsid protein. Resonance assignments of protons and heteronuclei, as well as 1H-15N dipolar and 1HN CSA tensors are readily obtained from the high sensitivity and resolution proton-detected 3D experiments. The approach demonstrated here is expected to enable the determination of atomic-resolution structures of large protein assemblies, inaccessible by current methodologies.
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