3OW7

Crystal structure of the membrane fusion protein CusB from Escherichia coli.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.78 Å
  • R-Value Free: 0.324 
  • R-Value Work: 0.280 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure of the membrane fusion protein CusB from Escherichia coli.

Su, C.C.Yang, F.Long, F.Reyon, D.Routh, M.D.Kuo, D.W.Mokhtari, A.K.Van Ornam, J.D.Rabe, K.L.Hoy, J.A.Lee, Y.J.Rajashankar, K.R.Yu, E.W.

(2009) J.Mol.Biol. 393: 342-355

  • DOI: 10.1016/j.jmb.2009.08.029
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Gram-negative bacteria, such as Escherichia coli, frequently utilize tripartite efflux complexes belonging to the resistance-nodulation-division family to expel diverse toxic compounds from the cell. These systems contain a periplasmic membrane fusio ...

    Gram-negative bacteria, such as Escherichia coli, frequently utilize tripartite efflux complexes belonging to the resistance-nodulation-division family to expel diverse toxic compounds from the cell. These systems contain a periplasmic membrane fusion protein (MFP) that is critical for substrate transport. We here present the x-ray structures of the CusB MFP from the copper/silver efflux system of E. coli. This is the first structure of any MFPs associated with heavy-metal efflux transporters. CusB bridges the inner-membrane efflux pump CusA and outer-membrane channel CusC to mediate resistance to Cu(+) and Ag(+) ions. Two distinct structures of the elongated molecules of CusB were found in the asymmetric unit of a single crystal, which suggests the flexible nature of this protein. Each protomer of CusB can be divided into four different domains, whereby the first three domains are mostly beta-strands and the last domain adopts an entirely helical architecture. Unlike other known structures of MFPs, the alpha-helical domain of CusB is folded into a three-helix bundle. This three-helix bundle presumably interacts with the periplasmic domain of CusC. The N- and C-termini of CusB form the first beta-strand domain, which is found to interact with the periplasmic domain of the CusA efflux pump. Atomic details of how this efflux protein binds Cu(+) and Ag(+) were revealed by the crystals of the CusB-Cu(I) and CusB-Ag(I) complexes. The structures indicate that CusB consists of multiple binding sites for these metal ions. These findings reveal novel structural features of an MFP in the resistance-nodulation-division efflux system and provide direct evidence that this protein specifically interacts with transported substrates.


    Organizational Affiliation

    Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, 50011, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cation efflux system protein cusB
A, B
413Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: cusB (ylcD)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Multi-Drug Efflux Transporters
Protein: 
CusA metal-ion efflux pump
Find proteins for P77239 (Escherichia coli (strain K12))
Go to UniProtKB:  P77239
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CU1
Query on CU1

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.78 Å
  • R-Value Free: 0.324 
  • R-Value Work: 0.280 
  • Space Group: I 2 2 2
Unit Cell:
Length (Å)Angle (°)
a = 84.237α = 90.00
b = 111.008β = 90.00
c = 258.867γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
PHENIXrefinement
PHASERphasing
ADSCdata collection
HKL-2000data reduction
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2010-09-17 
  • Released Date: 2010-11-17 
  • Deposition Author(s): Su, C.-C.
  • This entry supersedes: 3H9T

Revision History 

  • Version 1.0: 2010-11-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance