PDBsum entry: 1u00

Chaperone

PDB id: 1u00

Contents

Protein chain

227 a.a. *

Ligands

GLU-LEU-PRO-PRO-VAL-LYS-ILE-HIS-CYS

Waters ×259

* Residue conservation analysis

PDB id:

1u00

Name:

Chaperone

Title:

Hsca substrate binding domain complexed with the iscu recognition peptide elppvkihc

Structure:

Chaperone protein hsca. Chain: a. Fragment: hsca substrate binding domain. Synonym: hsc66. Engineered: yes. Iscu recognition peptide. Chain: p. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Gene: hsca. Expressed in: escherichia coli. Expression_system_taxid: 562. Synthetic: yes

Biol. unit:

Dimer (from PQS)

Resolution:

1.95Å R-factor: 0.178 R-free: 0.210

Authors:

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

Key ref:

J.R.Cupp-Vickery et al. (2004). Crystal structure of the molecular chaperone HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC. J Mol Biol, 342, 1265-1278. PubMed id: 15351650 DOI: 10.1016/j.jmb.2004.07.025

Date:

12-Jul-04 Release date: 05-Oct-04

Protein chain

P0A6Z1  (HSCA_ECOLI) -  Chaperone protein hscA

Seq: 616 a.a.

Struc: 227 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

 Gene Ontology (GO) functional annotation 

• Biochemical function: ATP binding (1 term)

DOI no: 10.1016/j.jmb.2004.07.025

J Mol Biol 342:1265-1278 (2004)

PubMed id: 15351650

Crystal structure of the molecular chaperone HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC.

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

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.