3PIK

Outer membrane protein CusC

• PDB DOI: https://doi.org/10.2210/pdb3PIK/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Escherichia coli
• Mutation(s): No 
• Membrane Protein: Yes  OPMPDBTMMemProtMD


• Deposited: 2010-11-06 Released: 2011-02-02 
• Deposition Author(s): van den Berg, B.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.243 
• R-Value Work: 0.197 
• R-Value Observed: 0.200 

Literature

Crystal Structure of Escherichia coli CusC, the Outer Membrane Component of a Heavy Metal Efflux Pump.

Kulathila, R., Kulathila, R., Indic, M., van den Berg, B.

(2011) PLoS One 6: e15610-e15610

• PubMed: 21249122 
• DOI: https://doi.org/10.1371/journal.pone.0015610
• Primary Citation of Related Structures:  
  3PIK


• PubMed Abstract: 
  

  While copper has essential functions as an enzymatic co-factor, excess copper ions are toxic for cells, necessitating mechanisms for regulating its levels. The cusCBFA operon of E. coli encodes a four-component efflux pump dedicated to the extrusion of Cu(I) and Ag(I) ions. We have solved the X-ray crystal structure of CusC, the outer membrane component of the Cus heavy metal efflux pump, to 2.3 Å resolution. The structure has the largest extracellular opening of any outer membrane factor (OMF) protein and suggests, for the first time, the presence of a tri-acylated N-terminal lipid anchor. The CusC protein does not have any obvious features that would make it specific for metal ions, suggesting that the narrow substrate specificity of the pump is provided by other components of the pump, most likely by the inner membrane component CusA.

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Organizational Affiliation: 

University of Massachusetts Medical School, Program in Molecular Medicine, Worcester, Massachusetts, United States of America.

Biological Assembly 1  

Global Symmetry: Cyclic - C3  (Explore in 3D)
Global Stoichiometry: Homo 3-mer - A3 

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

Macromolecule Content

• Total Structure Weight: 50.06 kDa 
• Atom Count: 3,602 
• Modelled Residue Count: 429 
• Deposited Residue Count: 446 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cation efflux system protein cusC	A	446	Escherichia coli	Mutation(s): 0  Gene Names: cusC, ibeB, ylcB, b0572, JW0561 Membrane Entity: Yes
UniProt
Find proteins for P77211 (Escherichia coli (strain K12)) Explore P77211  Go to UniProtKB:  P77211

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	D [auth A], E [auth A], F [auth A], G [auth A], H [auth A], I [auth A], J [auth A]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L
UNL	B [auth A], C [auth A]	Unknown ligand QAOWNCQODCNURD-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.30 Å
• R-Value Free: 0.243 
• R-Value Work: 0.197 
• R-Value Observed: 0.200 
• Space Group: H 3 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 89.03	α = 90
b = 89.03	β = 90
c = 473.037	γ = 120

Software Package:

Software Name	Purpose
HKL-2000	data collection
PHASER	phasing
PHENIX	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2011-02-02 
Deposition Author(s): van den Berg, B.

Revision History  

• Version 1.0: 2011-02-02
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2024-04-03
  Changes: Data collection, Database references, Derived calculations, Refinement description