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Lipid–Protein Nanodiscs: Possible Application in High-Resolution NMR Investigations of Membrane Proteins and Membrane-Active Peptides

Z. O. Shenkarev*, E. N. Lyukmanova, O. I. Solozhenkin, I. E. Gagnidze, O. V. Nekrasova, V. V. Chupin, A. A. Tagaev, Z. A. Yakimenko, T. V. Ovchinnikova, M. P. Kirpichnikov, and A. S. Arseniev*

Shemyakin–Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; fax: (495) 335-5033; E-mail: zh@nmr.ru; aars@nmr.ru

* To whom correspondence should be addressed.

Received January 26, 2009; Revision received February 6, 2009
High-resolution NMR is shown to be applicable for investigation of membrane proteins and membrane-active peptides embedded into lipid–protein nanodiscs (LPNs). 15N-Labeled K+-channel from Streptomyces lividans (KcsA) and the antibiotic antiamoebin I from Emericellopsis minima (Aam-I) were embedded in LPNs of different lipid composition. Formation of stable complexes undergoing isotropic motion in solution was confirmed by size-exclusion chromatography and 31P-NMR spectroscopy. The 2D 1H-15N-correlation spectra were recorded for KcsA in the complex with LPN containing DMPC and for Aam-I in LPNs based on DOPG, DLPC, DMPC, and POPC. The spectra recorded were compared with those in detergent-containing micelles and small bicelles commonly used in high-resolution NMR spectroscopy of membrane proteins. The spectra recorded in LPN environments demonstrated similar signal dispersion but significantly increased 1HN line width. The spectra of Aam-I embedded in LPNs containing phosphatidylcholine showed significant selective line broadening, thus suggesting exchange process(es) between several membrane-bound states of the peptide. 15N relaxation rates were measured to obtain the effective rotational correlation time of the Aam-I molecule. The obtained value (~40 nsec at 45°C) is indicative of additional peptide motions within the Aam-I/LPN complex.
KEY WORDS: nanodisc, apolipoprotein, high-density lipoprotein particle, membrane protein, membrane-active peptide, model membranes, NMR spectroscopy

DOI: 10.1134/S0006297909070086