7KF5

Cryo-electron microscopy structure of the heavy metal efflux pump CusA in the symmetric closed state

Summary for 7KF5

• Entry DOI: 10.2210/pdb7kf5/pdb
• EMDB information: 22843
• Descriptor: Cation efflux system protein CusA (1 entity in total)
• Functional Keywords: efflux, pump, heavy metal. copper, silver, closed, open, transport, membrane protein, transport protein
• Biological source: Escherichia coli
• Total number of polymer chains: 3
• Total formula weight: 347501.84

Authors

Moseng, M.A. (deposition date: 2020-10-13, release date: 2021-04-14, Last modification date: 2024-03-06)

Primary citation

Moseng, M.A.,Lyu, M.,Pipatpolkai, T.,Glaza, P.,Emerson, C.C.,Stewart, P.L.,Stansfeld, P.J.,Yu, E.W.
Cryo-EM Structures of CusA Reveal a Mechanism of Metal-Ion Export.
Mbio, 12:-, 2021

PubMed Abstract: Gram-negative bacteria utilize the resistance-nodulation-cell division (RND) superfamily of efflux pumps to expel a variety of toxic compounds from the cell. The CusA membrane protein, which recognizes and extrudes biocidal Cu(I) and Ag(I) ions, belongs to the heavy-metal efflux (HME) subfamily of RND efflux pumps. We here report four structures of the trimeric CusA heavy-metal efflux pump in the presence of Cu(I) using single-particle cryo-electron microscopy (cryo-EM). We discover that different CusA protomers within the trimer are able to bind Cu(I) ions simultaneously. Our structural data combined with molecular dynamics (MD) simulations allow us to propose a mechanism for ion transport where each CusA protomer functions independently within the trimer. The bacterial RND superfamily of efflux pumps mediate resistance to a variety of biocides, including Cu(I) and Ag(I) ions. Here we report four cryo-EM structures of the trimeric CusA pump in the presence of Cu(I). Combined with MD simulations, our data indicate that each CusA protomer within the trimer recognizes and extrudes Cu(I) independently.

PubMed: 33820823
DOI: 10.1128/mBio.00452-21

Experimental method

ELECTRON MICROSCOPY (3.2 Å)