Hydrogen-deuterium exchange mass spectrometry of membrane proteins in lipid nanodiscs

• Published in: Chemistry and physics of lipids 2019-05, Vol.220, p.14-22
• Main Authors: Redhair, Michelle, Clouser, Amanda F., Atkins, William M.
• Format: Article
• Language: English
• Subjects: Conformational dynamics; Conformational exchange; Deuterium Exchange Measurement; H/DX mass spectrometry; Lipids - chemistry; Mass Spectrometry; Membrane protein; Membrane Proteins - chemistry; Nanodisc; Nanostructures - chemistry
• ISSN: 0009-3084; 1873-2941
• DOI: 10.1016/j.chemphyslip.2019.02.007

•H/DX mass spectrometry enables interrogation of backbone dynamics and solvation of membrane proteins in a lipid environment.•Improvements in experimental workflow of H/DX MS with proteonanodiscs lead to increased peptide coverage, including some membrane spanning regions.•H/DX MS can be used to probe membrane topology, ligand binding, and protein-protein interactions of membrane proteins.•Existing literature examples of H/DX MS of proteins in nanodiscs reveal a wide range of behavior including combinations of EX1 and EX2 kinetics. Hydrogen deuterium exchange mass spectrometry (H/DX MS) provides a quantitative comparison of the relative rates of exchange of amide protons for solvent deuterons. In turn, the rate of amide exchange depends on a complex combination of the stability of local secondary structure, solvent accessibility, and dynamics. H/DX MS has, therefore, been widely used to probe structure and function of soluble proteins, but its application to membrane proteins was limited previously to detergent solubilized samples. The large excess of lipids from model membranes, or from membrane fractions derived from in vivo samples, presents challenges with mass spectrometry. The lipid nanodisc platform, consisting of apolipoprotein A-derived membrane scaffold proteins, provides a native like membrane environment in which to capture analyte membrane proteins with a well defined, and low, ratio of lipid to protein. Membrane proteins in lipid nanodiscs are amenable to H/DX MS, and this is expected to lead to a rapid increase in the number of membrane proteins subjected to this analysis. Here we review the few literature examples of the application of H/DX MS to membrane proteins in nanodiscs. The incremental improvements in the experimental workflow of the H/DX MS are described and potential applications of this approach to study membrane proteins are described.