HSP90 N-terminal domain bound to ACP
[HS90A_HUMAN] Molecular chaperone that promotes the maturation, structural maintenance and proper regulation of specific target proteins involved for instance in cell cycle control and signal transduction. Undergoes a functional cycle that is linked to its ATPase activity. 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. 
Publication Abstract from PubMed
The activation of molecular chaperone heat-shock protein 90 (Hsp90) is dependent on ATP binding and hydrolysis, which occurs in the N-terminal domains of protein. Here, we have determined three crystal structures of the N-terminal domain of human Hsp90 in native and in complex with ATP and ATP analog, providing a clear view of the catalytic mechanism of ATP hydrolysis by Hsp90. Additionally, the binding of ATP leads the N-terminal domains to be an intermediate state that could be used to partially explain why the isolated N-terminal domain of Hsp90 has very weak ATP hydrolytic activity.
Structure insights into mechanisms of ATP hydrolysis and the activation of human heat-shock protein 90.,Li J, Sun L, Xu C, Yu F, Zhou H, Zhao Y, Zhang J, Cai J, Mao C, Tang L, Xu Y, He J Acta Biochim Biophys Sin (Shanghai). 2012 Apr;44(4):300-6. doi:, 10.1093/abbs/gms001. Epub 2012 Feb 7. PMID:22318716
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.