Biological Assembly 1  

 3D View: Structure | Electron Density

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

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

Macromolecule Content

• Total Structure Weight: 51132.72 
• Atom Count: 3033 
• Residue Count: 459 
• Unique protein chains: 1

1SG2

Crystal structure of the periplasmic chaperone Skp

• DOI: 10.2210/pdb1SG2/pdb

• Classification: CHAPERONE
• Organism(s): Escherichia coli (strain K12)
• Expression System: Escherichia coli


• Deposited: 2004-02-23 Released: 2004-09-14 
• Deposition Author(s): Korndorfer, I.P., Dommel, M.K., Skerra, A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.35 Å
• R-Value Free: 0.279 
• R-Value Work: 0.223 

Literature

Structure of the periplasmic chaperone Skp suggests functional similarity with cytosolic chaperones despite differing architecture.

Korndorfer, I.P., Dommel, M.K., Skerra, A.

(2004) Nat.Struct.Mol.Biol. 11: 1015-1020

• PubMed: 15361861 
• DOI: 10.1038/nsmb828


• PubMed Abstract: 
  

The 17-kDa protein (Skp) of Escherichia coli is a homotrimeric periplasmic chaperone for newly synthesized outer-membrane proteins. Here we present its X-ray structure at a resolution of 2.35 A. Three hairpin-shaped alpha-helical extensions reach out by approximately 60 A from a trimerization domain, which is composed of three intersubunit beta-sheets that wind around a central axis. The alpha-helical extensions approach each other at their distal turns, resulting in a fold that resembles a 'three-pronged grasping forceps'. The overall shape of Skp is reminiscent of the cytosolic chaperone prefoldin, although it is based on a radically different topology. The peculiar architecture, with apparent plasticity of the prongs and distinct electrostatic and hydrophobic surface properties, supports the recently proposed biochemical mechanism of this chaperone: formation of a Skp(3)-Omp complex protects the outer membrane protein from aggregation during passage through the bacterial periplasm.

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Related Citations: 

• The periplasmic E. coli chaperone Skp is a trimer in solution: biophysical and preliminary crystallographic characterization
  Schlapschy, M.,Dommel, M.K.,Hadian, K.,Fogarasi, M.,Korndoerfer, I.P.,Skerra, A.
  () TO BE PUBLISHED --: --




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Organizational Affiliation: 

Lehrstuhl für Biologische Chemie, Technische Universität München, 85350 Freising-Weihenstephan, Germany.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Seventeen Kilodalton Protein	A, B, C	153	Escherichia coli (strain K12)	Mutation(s): 0  Gene Names: skp (hlpA, ompH)
Find proteins for P0AEU7 (Escherichia coli (strain K12)) Go to UniProtKB:  P0AEU7

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.35 Å
• R-Value Free: 0.279 
• R-Value Work: 0.223 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length (Å)	Angle (°)
a = 54.985	α = 90.00
b = 83.911	β = 90.00
c = 158.378	γ = 90.00

Software Package:

Software Name	Purpose
REFMAC	refinement
CCP4	data scaling
MOSFLM	data reduction
SHELXS	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-02-23 
• Released Date: 2004-09-14 
• Deposition Author(s): Korndorfer, I.P., Dommel, M.K., Skerra, A.

Revision History 

• Version 1.0: 2004-09-14
  Type: Initial release
• Version 1.1: 2008-04-29
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Advisory, Version format compliance