Diffusion of Peptides and Small Molecules Encapsulated in Lipidic Cubic Phases by Band-Selective Excitation Short Transient ¹H PGSE NMR

In model membrane systems, such as lipidic cubic phases (LCPs), ¹H NMR spectra are dominated by resonances from water and lipid molecules. The measurement of translational diffusion of peptides/molecules encapsulated in LCPs using conventional ¹H pulsed-gradient spin-echo (PGSE) NMR is, therefore, immensely difficult due to the dynamic range caused by the intense resonance(s) from the surrounding environment. The present study reports the use of a band-selective short transient PGSE sequence, avoiding the perturbation of both hydration water and lipids, for measuring the diffusion of molecules encapsulated within the lipid bilayer and the aqueous channels of LCPs.