Contributions of the LPPVK Motif of the Iron-Sulfur Template Protein IscU to Interactions with the Hsc66-Hsc20 Chaperone System

Hsc66 (HscA) and Hsc20 (HscB) from Escherichia coli comprise a specialized chaperone system that selectively binds the iron-sulfur cluster template protein IscU. Hsc66 interacts with peptides corresponding to a discrete region of IscU including residues 99–103 (LPPVK), and a peptide containing resid...

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Bibliographic Details
Published in:The Journal of biological chemistry 2003-09, Vol.278 (39), p.37582-37589
Main Authors: Hoff, Kevin G., Cupp-Vickery, Jill R., Vickery, Larry E.
Format: Article
Language:English
Subjects:
Amino Acid Motifs
Escherichia coli
Escherichia coli Proteins - chemistry
Escherichia coli Proteins - metabolism
Heat-Shock Proteins - metabolism
Hsc20 protein
Hsc66 protein
HSP70 Heat-Shock Proteins - metabolism
Iron-Sulfur Proteins - chemistry
Iron-Sulfur Proteins - metabolism
IscU protein
Models, Molecular
Molecular Chaperones - metabolism
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Summary:Hsc66 (HscA) and Hsc20 (HscB) from Escherichia coli comprise a specialized chaperone system that selectively binds the iron-sulfur cluster template protein IscU. Hsc66 interacts with peptides corresponding to a discrete region of IscU including residues 99–103 (LPPVK), and a peptide containing residues 98–106 stimulates Hsc66 ATPase activity in a manner similar to IscU. To determine the relative contributions of individual residues in the LPPVK motif to Hsc66 binding and regulation, we have carried out an alanine mutagenesis scan of this motif in the Glu98–Cys106 peptide and the IscU protein. Alanine substitutions in the Glu98–Cys106 peptide resulted in decreased ATPase stimulation (2–10-fold) because of reduced binding affinity, with peptide(P101A) eliciting
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M305292200