Yamamoto K, Xu J, Kawulka KE, Vederas JC, Ramamoorthy A. Use of a copper-chelated lipid speeds up NMR measurements from membrane proteins.
J Am Chem Soc 2010;
132:6929-31. [PMID:
20433169 DOI:
10.1021/ja102103n]
[Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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 (15)N-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.
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