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| {{STRUCTURE_1u00| PDB=1u00 | SCENE= }} | | {{STRUCTURE_1u00| PDB=1u00 | SCENE= }} |
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| '''HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC'''
| | ===HscA substrate binding domain complexed with the IscU recognition peptide ELPPVKIHC=== |
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| ==Overview==
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| 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.
| | The line below this paragraph, {{ABSTRACT_PUBMED_15351650}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 15351650 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_15351650}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Hsp70]] | | [[Category: Hsp70]] |
| [[Category: Iscu]] | | [[Category: Iscu]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 10:34:36 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 09:47:33 2008'' |
