Biological Assembly 1  

 3D View: Structure | Electron Density | Predict Membrane 

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 90.36 kDa 
• Atom Count: 4548 
• Modelled Residue Count: 594 
• Deposited Residue Count: 826 
• Unique protein chains: 1

3OOC

Crystal structure of the membrane fusion protein CusB from Escherichia coli

• DOI: 10.2210/pdb3OOC/pdb
• Entry: 3OOC supersedes: 3H9I

• Classification: TRANSPORT PROTEIN
• Organism(s): Escherichia coli K-12
• Expression System: Escherichia coli
• Mutation(s): No 
• Membrane Protein: Yes  mpstruc


• Deposited: 2010-08-30 Released: 2010-12-29 
• Deposition Author(s): 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.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.40 Å
• R-Value Free: 0.318 
• R-Value Work: 0.261 
• R-Value Observed: 0.264 

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

• PubMed: 19695261 
• DOI: 10.1016/j.jmb.2009.08.029
• Primary Citation of Related Structures:  
  3H94, 3OOC, 3OPO, 3OW7


• 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 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.

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Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cation efflux system protein cusB	A, B	413	Escherichia coli K-12	Mutation(s): 0  Gene Names: cusB, ylcD, b0574, JW0563 Membrane Entity: Yes
UniProt
Find proteins for P77239 (Escherichia coli (strain K12)) Explore P77239  Go to UniProtKB:  P77239

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.40 Å
• R-Value Free: 0.318 
• R-Value Work: 0.261 
• R-Value Observed: 0.264 
• Space Group: I 2 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 84.962	α = 90
b = 113.244	β = 90
c = 258.942	γ = 90

Software Package:

Software Name	Purpose
DENZO	data reduction
SCALEPACK	data scaling
SHARP	phasing
DM	phasing
PHENIX	refinement
PDB_EXTRACT	data extraction
ADSC	data collection

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2010-08-30 
• Released Date: 2010-12-29 
Deposition Author(s): 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.
• This entry supersedes: 3H9I

Revision History  

• Version 1.0: 2010-12-29
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance