Use of a Copper-Chelated Lipid Speeds Up NMR Measurements from Membrane Proteins

• Published in: Journal of the American Chemical Society Vol. 132; no. 20; pp. 6929 - 6931
• Main Authors: Yamamoto, Kazutoshi, Xu, Jiadi, Kawulka, Karen E, Vederas, John C, Ramamoorthy, Ayyalusamy
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 26.05.2010
• Subjects: Chelating Agents - chemistry; Copper - chemistry; Lipid Bilayers - chemistry; Magnetic Resonance Spectroscopy - methods; Membrane Proteins - chemistry; Time Factors
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja102103n

Recent studies have demonstrated the abilities of solid-state NMR techniques to solve atomic-level-resolution structures and dynamics of membrane-associated proteins and peptides. However, high-throughput applications of solid-state NMR spectroscopy are hampered by long acquisition times due to the low sensitivity of the technique. In this study, we demonstrate the use of a paramagnetic copper-chelated lipid to enhance the spin−lattice relaxation and thereby speed up solid-state NMR measurements. Fluid lamellar-phase bicelles composed of a lipid, detergent, and the copper-chelated lipid and containing a uniformly 15N-labeled antimicrobial peptide, subtilosin A, were used at room temperature. The use of a chelating lipid reduces the concentration of free copper and limits RF-induced heating, a major problem for fluid samples. Our results demonstrate a 6.2-fold speed increase and a 2.7-fold improvement in signal-to-noise ratio for solid-state NMR experiments under magic-angle spinning and static conditions, respectively. Furthermore, solid-state NMR measurements are shown to be feasible even for nanomole concentrations of a membrane-associated peptide.