PDBsum entry 2j8s

Membrane protein

PDB id: 2j8s

Contents

Protein chains

1044 a.a. *

156 a.a. *

Ligands

LMT ×10

LMU

Waters ×350

* Residue conservation analysis

PDB id:

2j8s

Name:

Membrane protein

Title:

Drug export pathway of multidrug exporter acrb revealed by darpin inhibitors

Structure:

Acriflavine resistance protein b. Chain: a, b, c. Synonym: acrb. Engineered: yes. Darpin. Chain: d, e. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k-12. Expressed in: escherichia coli. Expression_system_taxid: 469008. Synthetic construct. Organism_taxid: 32630. Expression_system_taxid: 562.

Resolution:

2.54Å R-factor: 0.229 R-free: 0.271

Authors:

G.Sennhauser,P.Amstutz,C.Briand,O.Storchenegger,M.G.Gruetter

Key ref:

G.Sennhauser et al. (2007). Drug export pathway of multidrug exporter AcrB revealed by DARPin inhibitors. PLoS Biol, 5, 0. PubMed id: 17194213 DOI: 10.1371/journal.pbio.0050007

Date:

27-Oct-06 Release date: 23-Jan-07

Protein chains

P31224  (ACRB_ECOLI) -  Multidrug efflux pump subunit AcrB from Escherichia coli (strain K12)

Seq: 1049 a.a.

Struc: 1044 a.a.

Protein chains

No UniProt id for this chain

Struc: 156 a.a.

DOI no: 10.1371/journal.pbio.0050007

PLoS Biol 5:0 (2007)

PubMed id: 17194213

Drug export pathway of multidrug exporter AcrB revealed by DARPin inhibitors.

G.Sennhauser, P.Amstutz, C.Briand, O.Storchenegger, M.G.Grütter.

ABSTRACT

The multidrug exporter AcrB is the inner membrane component of the AcrAB-TolC drug efflux system in Escherichia coli and is responsible for the resistance of this organism to a wide range of drugs. Here we describe the crystal structure of the trimeric AcrB in complex with a designed ankyrin-repeat protein (DARPin) inhibitor at 2.5-A resolution. The three subunits of AcrB are locked in different conformations revealing distinct channels in each subunit. There seems to be remote conformational coupling between the channel access, exit, and the putative proton-translocation site, explaining how the proton motive force is used for drug export. Thus our structure suggests a transport pathway not through the central pore but through the identified channels in the individual subunits, which greatly advances our understanding of the multidrug export mechanism.

Selected figure(s)

Figure 4.
Figure 4.The Extension of the Channels in the Individual Subunits of AcrB
The view is the same as in Figure 2A. For simplicity, the DARPins are not shown. The channels are colored in transparent blue. The potential export pathway is represented by dashed lines. The loop forming the bottom of the periplasmic channel entrance (PE) and TM helix 8 are highlighted in red. The gate to the central funnel formed by the residues Gln124, Gln125, and Tyr758 is shown in space filling representation for clarity.
(A) In subunit A, the channel is opened to the periplasm, while the gate is in the closed conformation. The pore domain subdomains are labeled.
(B) In subunit B, the channel displays an open conformation to the periplasm and to the membrane bilayer (CE). The gate is in a closed conformation.
(C) Subunit C displays a closed conformation of the channel entrances, while the gate is open, extending the channel to the central funnel.

Figure 5.
Figure 5.Conformational Changes in the TM Region of AcrB
(A) Wire model of the superpositioned TM domains of subunit A and subunit C viewed from the periplasmic side. Subunit B is omitted since it displays a similar conformation as subunit A. The individual helices are labeled.
(B) Detailed interactions of the amino acid residues in the putative proton-translocation site viewed in the same orientation as in (A). Residues involved in the hydrogen-bonded network (dashed lines) are labeled. The |Fo-Fc| omit electron density map (blue mesh) of Lys940 in subunit C is contoured at 3.5 σ.

The above figures are reprinted from an Open Access publication published by Public Library of Science: PLoS Biol (2007, 5, 0-0) copyright 2007.

Figures were selected by an automated process.