5NIL

Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump-MacB section

Summary for 5NIL

• Entry DOI: 10.2210/pdb5nil/pdb
• EMDB information: 3653
• Descriptor: Outer membrane protein TolC, Macrolide export protein MacA, Macrolide export ATP-binding/permease protein MacB (3 entities in total)
• Functional Keywords: abc transporter, drug efflux pump, multi-drug resistance, macrolide transporter, toxin transporter, transport protein
• Biological source: Escherichia coli (strain K12); More
• Total number of polymer chains: 11
• Total formula weight: 545014.30

Authors

Fitzpatrick, A.W.P.,Llabres, S.,Neuberger, A.,Blaza, J.N.,Bai, X.-C.,Okada, U.,Murakami, S.,van Veen, H.W.,Zachariae, U.,Scheres, S.H.W.,Luisi, B.F.,Du, D. (deposition date: 2017-03-24, release date: 2017-05-24, Last modification date: 2024-05-15)

Primary citation

Fitzpatrick, A.W.P.,Llabres, S.,Neuberger, A.,Blaza, J.N.,Bai, X.C.,Okada, U.,Murakami, S.,van Veen, H.W.,Zachariae, U.,Scheres, S.H.W.,Luisi, B.F.,Du, D.
Structure of the MacAB-TolC ABC-type tripartite multidrug efflux pump.
Nat Microbiol, 2:17070-17070, 2017

PubMed Abstract: The MacA-MacB-TolC assembly of Escherichia coli is a transmembrane machine that spans the cell envelope and actively extrudes substrates, including macrolide antibiotics and polypeptide virulence factors. These transport processes are energized by the ATPase MacB, a member of the ATP-binding cassette (ABC) superfamily. We present an electron cryo-microscopy structure of the ABC-type tripartite assembly at near-atomic resolution. A hexamer of the periplasmic protein MacA bridges between a TolC trimer in the outer membrane and a MacB dimer in the inner membrane, generating a quaternary structure with a central channel for substrate translocation. A gating ring found in MacA is proposed to act as a one-way valve in substrate transport. The MacB structure features an atypical transmembrane domain with a closely packed dimer interface and a periplasmic opening that is the likely portal for substrate entry from the periplasm, with subsequent displacement through an allosteric transport mechanism.

PubMed: 28504659
DOI: 10.1038/nmicrobiol.2017.70

Experimental method

ELECTRON MICROSCOPY (5.3 Å)