Chromatographic Phospholipid Trapping for Automated H/D Exchange Mass Spectrometry of Membrane Protein–Lipid Assemblies

Dietmar Hammerschmid*, Valeria Calvaresi, Chloe Bailey, Ben Russell Lewis, Argyris Politis, Michael Morris, Laetitia Denbigh, Malcolm Anderson, Eamonn Reading*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

Lipid interactions modulate the function, folding, structure, and organization of membrane proteins. Hydrogen/deuterium exchange mass spectrometry (HDX-MS) has emerged as a useful tool to understand the structural dynamics of these proteins within lipid environments. Lipids, however, have proven problematic for HDX-MS analysis of membrane-embedded proteins due to their presence of impairing proteolytic digestion, causing liquid chromatography column fouling, ion suppression, and/or mass spectral overlap. Herein, we describe the integration of a chromatographic phospholipid trap column into the HDX-MS apparatus to enable online sample delipidation prior to protease digestion of deuterium-labeled protein–lipid assemblies. We demonstrate the utility of this method on membrane scaffold protein–lipid nanodisc─both empty and loaded with the ∼115 kDa transmembrane protein AcrB─proving efficient and automated phospholipid capture with minimal D-to-H back-exchange, peptide carry-over, and protein loss. Our results provide insights into the efficiency of phospholipid capture by ZrO2-coated and TiO2 beads and describe how solution conditions can be optimized to maximize not only the performance of our online but also the existing offline, delipidation workflows for HDX-MS. We envision that this HDX-MS method will significantly ease membrane protein analysis, allowing to better interrogate their dynamics in artificial lipid bilayers or even native cell membranes.
Original languageEnglish
Pages (from-to)3002-3011
Number of pages10
JournalAnalytical Chemistry
Volume95
Issue number5
Early online date27 Jan 2023
DOIs
Publication statusPublished - 7 Feb 2023

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