title: Probing the Lipid Annular Belt by Gas-Phase Dissociation of Membrane Proteins in Nanodiscs.
abstract: Interactions between membrane proteins and lipids are often crucial for structure and function yet difficult to define because of their dynamic and heterogeneous nature. Here, we use mass spectrometry to demonstrate that membrane protein oligomers ejected from nanodiscs in the gas phase retain large numbers of lipid interactions. The complex mass spectra that result from gas-phase dissociation were assigned using a Bayesian deconvolution algorithm together with mass defect analysis, allowing us to count individual lipid molecules bound to membrane proteins. Comparison of the lipid distributions measured by mass spectrometry with molecular dynamics simulations reveals that the distributions correspond to distinct lipid shells that vary according to the type of protein-lipid interactions. Our results demonstrate that nanodiscs offer the potential for native mass spectrometry to probe interactions between membrane proteins and the wider lipid environment.
authors.affiliation: Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ (UK).
authors.forename: Michael T
authors.initials: MT
authors.lastname: Marty
authors.affiliation: Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ (UK).
authors.forename: Kin Kuan
authors.initials: KK
authors.lastname: Hoi
authors.affiliation: Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ (UK).
authors.forename: Joseph
authors.initials: J
authors.lastname: Gault
authors.affiliation: Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford OX1 3QZ (UK). carol.robinson@chem.ox.ac.uk.
authors.forename: Carol V
authors.initials: CV
authors.lastname: Robinson
mesh_terms: D005740:Gases / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000737:chemistry*; D049329:Nanostructures
chemical_list: D005740:Gases; D008055:Lipids; D008565:Membrane Proteins
keywords: lipid annulus; mass spectrometry; membrane proteins; nanodiscs; protein-lipid interactions