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ATP sensitive tryptophans of hsp90
B B Bartha1, K Ajtai, D O Toft
1Department of Biochemistry and Molecular Biology, Mayo Foundation, Rochester, MN 55905, USA.
Biophysical Chemistry
|August 6, 1998
Summary
This study reveals that Adenosine triphosphate (ATP) specifically binds to heat shock protein 90 (hsp90) near tryptophan residues. This interaction is crucial for understanding hsp90
Area of Science:
- Biochemistry
- Molecular Biology
- Protein-ligand interactions
Background:
- Heat shock protein 90 (hsp90) is a crucial molecular chaperone involved in various cellular processes.
- Understanding the binding mechanism of Adenosine triphosphate (ATP) to hsp90 is essential for elucidating its function.
Purpose of the Study:
- To investigate the interaction between ATP and hsp90 using fluorescence quenching techniques.
- To determine the binding mechanism and specificity of ATP to hsp90.
Main Methods:
- Fluorescence quenching of tryptophan residues in hsp90.
- Utilizing different quenchers (ATP and acrylamide) and varying temperatures.
- Analyzing quenching mechanisms (static vs. collisional) and inhibition kinetics.
Main Results:
- ATP and acrylamide exhibit distinct quenching mechanisms for free tryptophan.
- Hsp90 contains two classes of tryptophan residues with differing accessibility to quenchers.
- ATP competitively inhibits acrylamide quenching, indicating static quenching and proximity to tryptophan residues.
- The dissociation constant for ATP-hsp90 interaction suggests high specificity.
Conclusions:
- ATP binds specifically to hsp90 in close proximity to tryptophan residues.
- The interaction is primarily mediated by static quenching, implying a defined binding site.
- This study provides insights into the molecular details of ATP binding to hsp90.