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 and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 25.45 kDa 
• Atom Count: 1997 
• Modelled Residue Count: 236 
• Deposited Residue Count: 236 
• Unique protein chains: 2

1U00

HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC

• PDB DOI: 10.2210/pdb1U00/pdb

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


• Deposited: 2004-07-12 Released: 2004-10-05 
• Deposition Author(s): Cupp-Vickery, J.R., Peterson, J.C., Ta, D.T., Vickery, L.E.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.95 Å
• R-Value Free: 0.210 
• R-Value Work: 0.174 
• R-Value Observed: 0.178 

Literature

Crystal Structure of the Molecular Chaperone HscA Substrate Binding Domain Complexed with the IscU Recognition Peptide ELPPVKIHC.

Cupp-Vickery, J.R., Peterson, J.C., Ta, D.T., Vickery, L.E.

(2004) J Mol Biol 342: 1265-1278

• PubMed: 15351650 
• DOI: 10.1016/j.jmb.2004.07.025
• Primary Citation of Related Structures:  
  1U00


• PubMed Abstract: 
  

HscA, a specialized bacterial Hsp70-class molecular chaperone, interacts with the iron-sulfur cluster assembly protein IscU by recognizing a conserved LPPVK sequence motif. We report the crystal structure of the substrate-binding domain of HscA (SBD, residues 389-616) from Escherichia coli bound to an IscU-derived peptide, ELPPVKIHC. The crystals belong to the space group I222 and contain a single molecule in the asymmetric unit. Molecular replacement with the E.coli DnaK(SBD) model was used for phasing, and the HscA(SBD)-peptide model was refined to Rfactor=17.4% (Rfree=21.0%) at 1.95 A resolution. The overall structure of HscA(SBD) is similar to that of DnaK(SBD), although the alpha-helical subdomain (residues 506-613) is shifted up to 10 A relative to the beta-sandwich subdomain (residues 389-498) when compared to DnaK(SBD). The ELPPVKIHC peptide is bound in an extended conformation in a hydrophobic cleft in the beta-subdomain, which appears to be solvent-accessible via a narrow passageway between the alpha and beta-subdomains. The bound peptide is positioned in the reverse orientation of that observed in the DnaK(SBD)-NRLLLTG peptide complex placing the N and C termini of the peptide on opposite sides of the HscA(SBD) relative to the DnaK(SBD) complex. Modeling of the peptide in the DnaK-like forward orientation suggests that differences in hydrogen bonding interactions in the binding cleft and electrostatic interactions involving surface residues near the cleft contribute to the observed directional preference.

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Organizational Affiliation: 

Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA. [e-mail]

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Chaperone protein hscA	A	227	Escherichia coli	Mutation(s): 0  Gene Names: hscA
UniProt
Find proteins for P0A6Z1 (Escherichia coli (strain K12)) Explore P0A6Z1  Go to UniProtKB:  P0A6Z1

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
IscU recognition peptide	B [auth P]	9	N/A	Mutation(s): 0

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.95 Å
• R-Value Free: 0.210 
• R-Value Work: 0.174 
• R-Value Observed: 0.178 
• Space Group: I 2 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 62.761	α = 90
b = 83.34	β = 90
c = 128.734	γ = 90

Software Package:

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

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-07-12 
• Released Date: 2004-10-05 
Deposition Author(s): Cupp-Vickery, J.R., Peterson, J.C., Ta, D.T., Vickery, L.E.

Revision History  

• Version 1.0: 2004-10-05
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance