1am1
ATP BINDING SITE IN THE HSP90 MOLECULAR CHAPERONE
Structural highlights
FunctionHSP82_YEAST Molecular chaperone that promotes the maturation, structural maintenance and proper regulation of specific target proteins involved in cell cycle control and signal transduction. Undergoes a functional cycle that is linked to its ATPase activity. The nucleotide-free form of the dimer is found in an open conformation in which the N-termini are not dimerized and the complex is ready for client protein binding. Binding of ATP induces large conformational changes, resulting in the formation of a ring-like closed structure in which the N-terminal domains associate intramolecularly with the middle domain and also dimerize with each other, stimulating their intrinsic ATPase activity and acting as a clamp on the substrate. Finally, ATP hydrolysis results in the release of the substrate. This cycle probably induces conformational changes in the client proteins, thereby causing their activation. Interacts dynamically with various co-chaperones that modulate its substrate recognition, ATPase cycle and chaperone function. Required for growth at high temperatures.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedHsp90 molecular chaperones in eukaryotic cells play essential roles in the folding and activation of a range of client proteins involved in cell cycle regulation, steroid hormone responsiveness, and signal transduction. The biochemical mechanism of Hsp90 is poorly understood, and the involvement of ATP in particular is controversial. Crystal structures of complexes between the N-terminal domain of the yeast Hsp90 chaperone and ADP/ATP unambiguously identify a specific adenine nucleotide binding site homologous to the ATP-binding site of DNA gyrase B. This site is the same as that identified for the antitumor agent geldanamycin, suggesting that geldanamycin acts by blocking the binding of nucleotides to Hsp90 and not the binding of incompletely folded client polypeptides as previously suggested. These results finally resolve the question of the direct involvement of ATP in Hsp90 function. Identification and structural characterization of the ATP/ADP-binding site in the Hsp90 molecular chaperone.,Prodromou C, Roe SM, O'Brien R, Ladbury JE, Piper PW, Pearl LH Cell. 1997 Jul 11;90(1):65-75. PMID:9230303[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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