Biological and model membranes studied by nuclear magnetic resonance of spin one half nuclei

Abstract

There is an inherent anisotropy in biological and model membrane systems and this anisotropy has a profound influence on the nuclear magnetic resonance spectra of such systems. For nuclei with a quadrupole moment the quadrupole coupling usually dominates the NMR spectrum, while for nuclei with spin quantum number I = ½ dipolar couplings provides the most important effects. The quadrupole coupling only affects isolated spins and usually gives rise to simple spectra. The dipole interactions on the other hand couple several spins. In a lipid bilayer with a multitude of spin-½ nuclei these couplings can give rise to complicated manybody effects. Thus the interpretation of the NMR spectra of membrane systems poses problems but at the same time there is a lot of information to be gained.

The use of wide‐line [14N]nitrogen NMR as a probe in model membranes

“…To do this, it is essential to probe various positions in the lipid molecules. Because of the overabundance of hydrogen atoms, proton NMR spectra have been difficult to interpret [9,10] and give little information about the motion of a single segment of the lipid molecule. 3'P NMR [l I] has been successfully used to probe the head group region of phospholipids.…”

NMR Studies of Membrane Structure and Dynamics

“…Recent efforts have been directed toward developing spectroscopic probes that would circumvent the possible perturbations in the bilayer produced by the bulky nitroxide radical. Nuclear Magnetic Resonance (NMR) spectroscopy is a natural tool for this purpose and there has been considerable effort using IH, 2H, 13C, and 31p probes which are either endogenous or incorporated into the lipid molecule (3)(4)(5)(6)(7)(8)(9)(10)(11). These efforts constitute the subject of the present review.…”

“…The comprehensive biannual reviews of NMR studies on liquid crystals by Tiddy (10,11) also include extensive coverage of phospholipid systems. Finally, Wennerstr6m & Lindblom (9) have recently reviewed I = ½ NMR studies of model membrane systems. This review contains an excellent general discussion of the mathematical formalism necessary for describing systems in which second-rank tensor interactions are incompletely averaged.…”

Deuterium magnetic resonance: theory and application to lipid membranes

“…As a result the spectra contain a large number of overlapping resonances and are rather difficult to analyse. Nevertheless, important information on the structure and dynamic behaviour of lipid systems has been provided by these techniques (Wennerstrom & Lindblom, 1977). Deuterium magnetic resonance of membraneous systems differs from conventional proton or carbon-13 nmr by the following principal features.…”