title: Hydration and temperature dependence of 13C and 1H NMR spectra of the DMPC phospholipid membrane and complete resonance assignment of its crystalline state.
abstract: Inhomogeneous line broadening due to conformational distributions of molecules is one of the troublesome problems in solid-state NMR spectroscopy. The best possible way to avoid it is to crystallize the sample. Here, we present a highly resolved (13)C cross-polarization (CP) magic angle spinning (MAS) NMR spectrum of the highly ordered crystalline 1,2-dimyrystoyl-sn-glycero-3-phosphocholine (DMPC) and completely assigned it using two-dimensional (2D) solid-state NMR spectra, dipolar heteronuclear correlation (HETCOR) spectra, scalar heteronuclear J coupling based chemical shift correlation (MAS-J-HMQC) spectra, and Dipolar Assisted Rotational Resonance (DARR) spectra. A comparison between assigned chemical shift values by solid-state NMR in this study and the calculated chemical shift values for X-ray crystal DMPC structures shows good agreement, indicating that the two isomers in the crystalline DMPC take the same conformation as the X-ray crystal structure. The phase diagram of the low hydration level of DMPC (3 ≤ n(W) ≤ 12) determined by (1)H and (13)C NMR spectra indicates that DMPC takes a crystalline state only in a very narrow region around n(W) = 4 and T < 313 K. These findings provide us with conformational information on crystalline DMPC and the physical properties of DMPC at a low hydration level and can possibly help us obtain a highly resolved solid-state NMR spectrum of microcrystalline membrane-associated protein samples.
authors: Suntory Foundation for Life Sciences, Bioorganic Research Institute, Mishima-Gun, Osaka, Japan. nomura@sunbor.or.jp
authors: Kaoru
authors: K
authors: Nomura
authors: Masami
authors: M
authors: Lintuluoto
authors: Kenichi
authors: K
authors: Morigaki
mesh_terms: D002462:Cell Membrane / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D008968:Molecular Conformation; D012821:Silanes / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D012821:Silanes; D014867:Water; D004134:Dimyristoylphosphatidylcholine