A High Resolution Solid State NMR Approach for the Structural Studies of Bicelles

摘要

Bicelles are increasingly being used as membrane mimicking systems in NMR experiments to investigate the structure of membrane proteins. In this study, we demonstrate the effectiveness of a 2D solid-state NMR approach that can be used to measure the structural constraints such as heteronuclear dipolar couplings between ¹H, ¹³C and ³¹P nuclei in bicelles without the need for isotopic enrichment. This method does not require a high radio frequency power unlike the presently used rotating-frame separated-local-field (SLF) techniques like PISEMA. In addition, multiple dipolar couplings can be measured accurately and the presence of a strong dipolar coupling does not suppress the weak couplings. High resolution spectra obtained from magnetically aligned DMPC:DHPC bicelles even in the presence of peptides suggest that this approach will be useful in understanding lipid-protein interactions that play a vital role in shaping up the function of membrane proteins.