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Structure and functional relationships of Hsp90
Chrisostomos Prodromou1, Laurence H Pearl
1Section of Structural Biology, Institute of Cancer Research, Chester Beatty Laboratories, 237 Fulham Road, London SW3 6JB, UK. chris.prodromou@icr.ac.uk, laurence.pearl@icr.ac.uk
Current Cancer Drug Targets
|October 8, 2003
Summary
Heat shock protein 90 (Hsp90) function involves regulated ATPase activity influenced by co-chaperones. Structural and biochemical studies reveal how ATP binding and hydrolysis drive Hsp90 conformational changes essential for client protein interactions.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- Heat shock protein 90 (Hsp90) is a crucial molecular chaperone involved in protein homeostasis.
- Understanding Hsp90's mechanism requires detailed knowledge of its interactions with client proteins and co-chaperones.
Purpose of the Study:
- To elucidate the molecular mechanisms governing Hsp90's ATPase activity and conformational dynamics.
- To characterize the roles of key co-chaperones in regulating Hsp90 function.
Main Methods:
- X-ray crystallography for structure determination of Hsp90 domains.
- Biochemical assays to assess ATPase activity.
- Co-immunoprecipitation and other biochemical methods to identify and characterize Hsp90-co-chaperone complexes.
Main Results:
- Structural determination of Hsp90 N-terminal and middle regions provided insights into its ATP cycle.
- Co-chaperones Sti1 and Cdc37/p50 inhibit Hsp90 ATPase activity, stabilizing an 'open' state.
- Co-chaperone Sba1/p23 and Aha1 modulate ATPase activity, influencing the 'closed' state.
- Identification of a catalytic loop in the middle region essential for ATP hydrolysis.
Conclusions:
- Hsp90 function is intricately regulated by ATP binding, hydrolysis, and interactions with diverse co-chaperones.
- Structural insights into Hsp90 domains are critical for understanding its ATP-driven conformational changes and client protein interactions.