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A Mass‐Spectrometry‐Based Approach to Distinguish Annular and Specific Lipid Binding to Membrane Proteins
Author(s) -
Bolla Jani Reddy,
Corey Robin A.,
Sahin Cagla,
Gault Joseph,
Hummer Alissa,
Hopper Jonathan T. S.,
Lane David P.,
Drew David,
Allison Timothy M.,
Stansfeld Phillip J.,
Robinson Carol V.,
Landreh Michael
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201914411
Subject(s) - chemistry , flippase , mass spectrometry , membrane lipids , substrate (aquarium) , dimer , membrane protein , biophysics , membrane , plasma protein binding , biochemistry , chromatography , organic chemistry , biology , phospholipid , ecology , phosphatidylserine
Abstract Membrane proteins engage in a variety of contacts with their surrounding lipids, but distinguishing between specifically bound lipids, and non‐specific, annular interactions is a challenging problem. Applying native mass spectrometry to three membrane protein complexes with different lipid‐binding properties, we explore the ability of detergents to compete with lipids bound in different environments. We show that lipids in annular positions on the presenilin homologue protease are subject to constant exchange with detergent. By contrast, detergent‐resistant lipids bound at the dimer interface in the leucine transporter show decreased k off rates in molecular dynamics simulations. Turning to the lipid flippase MurJ, we find that addition of the natural substrate lipid‐II results in the formation of a 1:1 protein–lipid complex, where the lipid cannot be displaced by detergent from the highly protected active site. In summary, we distinguish annular from non‐annular lipids based on their exchange rates in solution.