6BAJ

Cryo-EM structure of lipid bilayer in the native cell membrane nanoparticles of AcrB

Summary for 6BAJ

• Entry DOI: 10.2210/pdb6baj/pdb
• EMDB information: 7074
• Descriptor: Multidrug efflux pump subunit AcrB, PHOSPHATIDYLETHANOLAMINE, DODECANE, ... (4 entities in total)
• Functional Keywords: lipid bilayer, native cell membrane nanoparticles system, resistance-nodulation-cell division (rnd) family, phospholipid, membrane protein
• Biological source: Escherichia coli (strain K12)
• Total number of polymer chains: 3
• Total formula weight: 368837.76

Authors

Qiu, W.,Fu, Z.,Guo, Y. (deposition date: 2017-10-13, release date: 2018-12-19, Last modification date: 2024-03-13)

Primary citation

Qiu, W.,Fu, Z.,Xu, G.G.,Grassucci, R.A.,Zhang, Y.,Frank, J.,Hendrickson, W.A.,Guo, Y.
Structure and activity of lipid bilayer within a membrane-protein transporter.
Proc.Natl.Acad.Sci.USA, 115:12985-12990, 2018

PubMed Abstract: Membrane proteins function in native cell membranes, but extraction into isolated particles is needed for many biochemical and structural analyses. Commonly used detergent-extraction methods destroy naturally associated lipid bilayers. Here, we devised a detergent-free method for preparing cell-membrane nanoparticles to study the multidrug exporter AcrB, by cryo-EM at 3.2-Å resolution. We discovered a remarkably well-organized lipid-bilayer structure associated with transmembrane domains of the AcrB trimer. This bilayer patch comprises 24 lipid molecules; inner leaflet chains are packed in a hexagonal array, whereas the outer leaflet has highly irregular but ordered packing. Protein side chains interact with both leaflets and participate in the hexagonal pattern. We suggest that the lipid bilayer supports and harmonizes peristaltic motions through AcrB trimers. In AcrB D407A, a putative proton-relay mutant, lipid bilayer buttresses protein interactions lost in crystal structures after detergent-solubilization. Our detergent-free system preserves lipid-protein interactions for visualization and should be broadly applicable.

PubMed: 30509977
DOI: 10.1073/pnas.1812526115

Experimental method

ELECTRON MICROSCOPY (3.2 Å)