NMR methods for measuring lateral diffusion in membranes

Lateral diffusion is a fundamental property of biological membrane components, important for a host of biomembrane functions. Although long studied, novel aspects of the relationship between the structure of membrane components and their lateral diffusion properties continue to emerge. NMR-based lateral diffusion measurements are complicated by the spectral broadening arising from the slow anisotropic motions in membranes. Nevertheless, both pulsed field gradient (PFG) and exchange spectroscopy (EXSY) methods can be adapted to permit NMR measurements of lateral diffusion in membranes. These variously will be described in overview, highlighting advantages and limitations of each, but with particular emphasis on results from our laboratory using 1H PFG NMR measurements in magnetically aligned bicelles and 31P CODEX (Centreband-Only-Detection-of-Exchange) measurements in spherical phospholipid vesicles.

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► We review NMR-based methods for measuring lateral diffusion in membranes.
► General aspects of lateral diffusion in membranes are covered first.
► NMR spectroscopy as applicable to membranes is described, emphasizing the effects of anisotropic motions.
► Pulsed field gradient NMR studies of membrane lateral diffusion are detailed.
► Newer exchange NMR methods for measuring lateral diffusion are introduced.