Nucleotide-dependent interactions within a specialized Hsp70/Hsp40 complex involved in Fe-S cluster biogenesis.
J Am Chem Soc
; 136(33): 11586-9, 2014 Aug 20.
Article
em En
| MEDLINE
| ID: mdl-25080945
ABSTRACT
The structural mechanism by which Hsp70-type chaperones interact with Hsp40-type co-chaperones has been of great interest, yet still remains a matter of debate. Here, we used solution NMR spectroscopy to investigate the ATP-/ADP-dependent interactions between Escherichia coli HscA and HscB, the specialized Hsp70/Hsp40 molecular chaperones that mediate iron-sulfur cluster transfer. We observed that NMR signals assigned to amino acid residues in the J-domain and its "HPD" motif of HscB broadened severely upon the addition of ATP-bound HscA, but these signals were not similarly broadened by ADP-bound HscA or the isolated nucleotide binding domain of HscA complexed with either ATP or ADP. An HscB variant with an altered HPD motif, HscB(H32A,P33A,D34A), failed to manifest WT-like NMR signal perturbations and also abolished WT-like stimulation of ATP hydrolysis by HscA. In addition, residues 153-171 in the C-terminal region of HscB exhibited NMR signal perturbations upon interaction with HscA, alone or complexed with ADP or ATP. These results demonstrate that the HPD motif in the J-domain of HscB directly interacts with ATP-bound HscA and suggest that a second, less nucleotide-dependent binding site for HscA resides in the C-terminal region of HscB.
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Choque Térmico HSP70
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Proteínas de Choque Térmico HSP40
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Proteínas Ferro-Enxofre
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Nucleotídeos
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article