Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 67.04 kDa 
• Atom Count: 4714 
• Modelled Residue Count: 602 
• Deposited Residue Count: 602 
• Unique protein chains: 1

1CII

COLICIN IA

• PDB DOI: 10.2210/pdb1CII/pdb

• Classification: TRANSMEMBRANE PROTEIN
• Organism(s): Escherichia coli
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 1997-01-08 Released: 1998-01-14 
• Deposition Author(s): Wiener, M., Freymann, D., Ghosh, P., Stroud, R.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 3.00 Å
• R-Value Free: 0.312 
• R-Value Work: 0.241 
• R-Value Observed: 0.241 

Literature

Crystal structure of colicin Ia.

Wiener, M., Freymann, D., Ghosh, P., Stroud, R.M.

(1997) Nature 385: 461-464

• PubMed: 9009197 
• DOI: 10.1038/385461a0
• Primary Citation of Related Structures:  
  1CII


• PubMed Abstract: 
  

The ion-channel forming colicins A, B, E1, Ia, Ib and N all kill bacterial cells selectively by co-opting bacterial active-transport pathways and forming voltage-gated ion conducting channels across the plasma membrane of the target bacterium. The crystal structure of colicin Ia reveals a molecule 210 A long with three distinct functional domains arranged along a backbone of two extraordinarily long alpha-helices. A central domain at the bend of the hairpin-like structure mediates specific recognition and binding to an outer-membrane receptor. A second domain mediates translocation across the outer membrane via the TonB transport pathway; the TonB-box recognition element of colicin Ia is on one side of three 80 A-long helices arranged as a helical sheet. A third domain is made up of 10 alpha-helices which form a voltage-activated and voltage-gated ion conducting channel across the plasma membrane of the target cell. The two 160 A-long alpha-helices that link the receptor-binding domain to the other domains enable the colicin Ia molecule to span the periplasmic space and contact both the outer and plasma membranes simultaneously during function.

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Related Citations: 

• The Domain Structure of the Ion Channel-Forming Protein Colicin Ia
  Ghosh, P., Mel, S.F., Stroud, R.M.
  (1994) Nat Struct Biol 1: 597

• The Structure and Function of Colicin Ia
  Ghosh, P.
  (1992) Thesis --: --

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Organizational Affiliation: 

S-964 Department of Biochemistry and Biophysics, University of California, San Francisco 94143-0448, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
COLICIN IA	A	602	Escherichia coli	Mutation(s): 0  Gene Names: cia
UniProt
Find proteins for P06716 (Escherichia coli) Explore P06716  Go to UniProtKB:  P06716

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 3.00 Å
• R-Value Free: 0.312 
• R-Value Work: 0.241 
• R-Value Observed: 0.241 
• Space Group: C 2 2 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 64.4	α = 90
b = 178.6	β = 90
c = 285.5	γ = 90

Software Package:

Software Name	Purpose
PHASES	phasing
SOLOMON	phasing
X-PLOR	model building
XTALVIEW	refinement
X-PLOR	refinement
DENZO	data reduction
SCALEPACK	data scaling
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1997-01-08 
• Released Date: 1998-01-14 
Deposition Author(s): Wiener, M., Freymann, D., Ghosh, P., Stroud, R.

Revision History  

• Version 1.0: 1998-01-14
  Type: Initial release
  
• Version 1.1: 2008-03-24
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance