On the Performance of Spin Diffusion NMR Techniques in Oriented Solids: Prospects for Resonance Assignments and Distance Measurements from Separated Local Field Experiments.
Related Articles On the Performance of Spin Diffusion NMR Techniques in Oriented Solids: Prospects for Resonance Assignments and Distance Measurements from Separated Local Field Experiments.
J Phys Chem B. 2010 Oct 11;
Authors: Traaseth NJ, Gopinath T, Veglia G
NMR spin diffusion experiments have the potential to provide both resonance assignment and internuclear distances for protein structure determination in oriented solid-state NMR. In this paper, we compared the efficiencies of three spin diffusion experiments: proton-driven spin diffusion (PDSD), cross-relaxation-driven spin diffusion (CRDSD), and proton-mediated proton transfer (PMPT). As model systems for oriented proteins, we used single crystals of N-acetyl-L-(15)N-leucine (NAL) and N-acetyl-L-(15)N-valyl-L-(15)N-leucine (NAVL) to probe long and short distances, respectively. We demonstrate that, for short (15)N/(15)N distances such as those found in NAVL (3.3 Å), the PDSD mechanism gives the most intense cross-peaks, while, for longer distances (>6.5 Å), the CRDSD and PMPT experiments are more efficient. The PDSD was highly inefficient for transferring magnetization across distances greater than 6.5 Å (NAL crystal sample), due to small (15)N/(15)N dipolar couplings (