Structural and functional basis for lipid synergy on the activity of the antibacterial peptide ABC transporter McjD

DOI: 10.1074/jbc.M116.732107

Authors: Shahid Mehmood (University of Oxford) , Valentina Corradi (University of Calgary) , Hassan Choudhury (Imperial College London) , Rohanah Hussain (Diamond Light Source) , Patrick Becker (Imperial College London) , Danny Axford (Diamond Light Source) , Severine Zirah (Museum National d'Histoire Naturelle) , Sylvie Rebuffat (Museum National d'Histoire Naturelle) , D. Peter Tieleman (University of Calgary) , Carol V. Robinson (Oxford Univiersity) , Konstantinos Beis (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Biological Chemistry

State: Published (Approved)
Published: August 2016
Diamond Proposal Number(s): 10136 , 14484

Abstract: The lipid bilayer is a dynamic environment that consists of a mixture of lipids with different properties that regulate the function of membrane proteins; these lipids are either annular, masking the protein hydrophobic surface, or specific lipids, essential for protein function. In this study, using tandem mass spectrometry, we have identified specific lipids associated with the Escherichia coli ABC transporter McjD, which translocates the antibacterial peptide MccJ25. Using non-denaturing mass spectrometry, we show that McjD in complex with MccJ25 survives the gas-phase. Partial delipidation of McjD resulted in reduced ATPase activity and thermostability as shown by Circular Dichroism, both of which could be restored upon addition of defined E. coli lipids. We have resolved a phosphatidylglycerol lipid associated with McjD at 3.4 Å resolution, while molecular dynamic simulations carried out in different lipid environments assessed the binding of specific lipids to McjD. Combined, our data show a synergistic effect of zwitterionic and negatively charged lipids on the activity of McjD; the zwitterionic lipids provide structural stability to McjD whereas the negatively charged lipids are essential for its function.

Journal Keywords: lipid, membrane transport; membrane protein; structure-function; structural biology; ABC transporter; non-denaturing mass spectrometry; molecular dynamics; delipidation; circular dichroism

Subject Areas: Biology and Bio-materials


Instruments: B23-Circular Dichroism , I24-Microfocus Macromolecular Crystallography

Added On: 28/08/2016 14:31

Documents:
21656.full.pdf

Discipline Tags:

Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Spectroscopy Macromolecular Crystallography (MX) Circular Dichroism (CD)