3KSS

Structure and Mechanism of the Heavy Metal Transporter CusA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.88 Å
  • R-Value Free: 0.325 
  • R-Value Work: 0.260 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structures of the CusA efflux pump suggest methionine-mediated metal transport.

Long, F.Su, C.C.Zimmermann, M.T.Boyken, S.E.Rajashankar, K.R.Jernigan, R.L.Yu, E.W.

(2010) Nature 467: 484-488

  • DOI: 10.1038/nature09395
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Gram-negative bacteria, such as Escherichia coli, frequently use tripartite efflux complexes in the resistance-nodulation-cell division (RND) family to expel various toxic compounds from the cell. The efflux system CusCBA is responsible for extruding ...

    Gram-negative bacteria, such as Escherichia coli, frequently use tripartite efflux complexes in the resistance-nodulation-cell division (RND) family to expel various toxic compounds from the cell. The efflux system CusCBA is responsible for extruding biocidal Cu(I) and Ag(I) ions. No previous structural information was available for the heavy-metal efflux (HME) subfamily of the RND efflux pumps. Here we describe the crystal structures of the inner-membrane transporter CusA in the absence and presence of bound Cu(I) or Ag(I). These CusA structures provide new structural information about the HME subfamily of RND efflux pumps. The structures suggest that the metal-binding sites, formed by a three-methionine cluster, are located within the cleft region of the periplasmic domain. This cleft is closed in the apo-CusA form but open in the CusA-Cu(I) and CusA-Ag(I) structures, which directly suggests a plausible pathway for ion export. Binding of Cu(I) and Ag(I) triggers significant conformational changes in both the periplasmic and transmembrane domains. The crystal structure indicates that CusA has, in addition to the three-methionine metal-binding site, four methionine pairs-three located in the transmembrane region and one in the periplasmic domain. Genetic analysis and transport assays suggest that CusA is capable of actively picking up metal ions from the cytosol, using these methionine pairs or clusters to bind and export metal ions. These structures suggest a stepwise shuttle mechanism for transport between these sites.


    Organizational Affiliation

    Molecular, Cellular and Developmental Biology Interdepartmental Graduate Program, Iowa State University, Iowa 50011, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cation efflux system protein cusA
A
1055Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: cusA (ybdE)
Find proteins for P38054 (Escherichia coli (strain K12))
Go to UniProtKB:  P38054
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CU1
Query on CU1

Download SDF File 
Download CCD File 
A
COPPER (I) ION
Cu
VMQMZMRVKUZKQL-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.88 Å
  • R-Value Free: 0.325 
  • R-Value Work: 0.260 
  • Space Group: H 3 2
Unit Cell:
Length (Å)Angle (°)
a = 180.363α = 90.00
b = 180.363β = 90.00
c = 287.980γ = 120.00
Software Package:
Software NamePurpose
ADSCdata collection
DENZOdata reduction
PDB_EXTRACTdata extraction
PHENIXrefinement
SCALEPACKdata scaling
HKL-2000data reduction
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2009-11-23 
  • Released Date: 2010-09-22 
  • Deposition Author(s): Su, C.-C.

Revision History 

  • Version 1.0: 2010-09-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Source and taxonomy, Version format compliance
  • Version 1.2: 2017-11-01
    Type: Refinement description