title: Study of phospholipid structure by 1H, 13C, and 31P dipolar couplings from two-dimensional NMR.
abstract: Various motionally averaged 31P-1H, 13C-1H, 1H-1H, and 31P-13C dipolar couplings were measured for natural-abundance and unoriented phosphocholine in the L alpha phase. The couplings were obtained and assigned by a variety of advanced and partly novel two-dimensional solid-state NMR experiments. Whereas 31P-1H and 31P-13C dipolar couplings provide long-range structural constraints, geminal 1H-1H couplings and the signs of 13C-1H couplings are important new elements in a segmental order-tensor analysis of the lipid headgroup and glycerol backbone. The implications of these measured dipolar couplings for the conformational exchange of the lipid headgroup and the bending of the headgroup from the glycerol backbone are discussed. These dipolar couplings are also analyzed semiquantitatively in terms of the segmental order tensor.
authors.affiliation: Materials Science Division, Lawrence Berkeley Laboratory, University of California, Berkeley 94720, USA.
authors.forename: M
authors.initials: M
authors.lastname: Hong
authors.forename: K
authors.initials: K
authors.lastname: Schmidt-Rohr
authors.forename: D
authors.initials: D
authors.lastname: Nanz
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D002247:Carbon Isotopes; D006859:Hydrogen / Q000737:chemistry; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000737:chemistry; D008968:Molecular Conformation; D015394:Molecular Structure; D010713:Phosphatidylcholines / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry*; D010758:Phosphorus / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D010743:Phospholipids; D010758:Phosphorus; D006859:Hydrogen