Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - ENABLE (Elucidating natural bilayer lipid environments)

Teaser

Recent developments in my laboratory had led to important new information concerning the role of lipids in mediating protein interactions. Given the transient nature of protein lipid interactions, the challenge was to develop a technology to study the dynamic membrane protein...

Summary

Recent developments in my laboratory had led to important new information concerning the role of lipids in mediating protein interactions. Given the transient nature of protein lipid interactions, the challenge was to develop a technology to study the dynamic membrane protein in its native lipid environment. This, in turn, would answer key questions about how lipids modulate protein interfaces, occupy different binding sites, modulate membrane protein structure and modify function in vivo. Given the importance of membrane proteins in physiology, and therefore as potential drug targets, understanding their modulation by lipids is a major step towards more effective drug development. The overall aim of the project therefore is to understand the effects of the natural lipid environment on membrane proteins.

Work performed

We commenced work on elucidating the chemical synergy between membrane proteins and endogenous lipids, demonstrating for the first time how lipids can act as molecular ‘glues’ and are instrumental in regulating oligomeric assemblies of membrane proteins. We extended this research to investigate selected G-protein coupled receptors (GPCRs) and found that lipids also mediated critical interactions. In parallel with this work we also commenced development of a native desorption electrospray ionisation (DESI) platform. Construction of this device enabled us to lift membrane proteins from planar targets, functionalised in-house, directly into the mass spectrometer for characterisation.

Final results

We had previously considered using lipid vesicles for use with the DESI platform, predicting that this would enable us to release membrane proteins directly from the vesicles. We realised, however, that we needed a sonication step to release them directly from lipid vesicles into the mass spectrometer. This gave rise to a spectacular breakthrough in which we were able to release protein complexes directly from their membrane environments in a process known as SoLVe-MS (Sonicated Lipid Vesicle- MS).