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ATP-binding properties of human Hsp90
T Scheibel1, S Neuhofen, T Weikl
1Institut für Biophysik und physikalische Biochemie, Universität Regensburg, 93040 Regensburg, Germany.
The Journal of Biological Chemistry
|July 25, 1997
Summary
Human heat shock protein 90 (Hsp90) does not tightly bind ATP or exhibit ATPase activity. Weak ATP binding was detected, but its functional significance remains unclear.
Area of Science:
- Molecular Biology
- Biochemistry
- Cell Biology
Background:
- Heat shock protein 90 (Hsp90) is a crucial chaperone in eukaryotic cells, involved in signaling pathways and maintaining receptor function.
- Hsp90 levels increase under cellular stress, and its chaperone function is often considered ATP-independent.
- Despite established yeast Hsp90 properties, ATP-dependent functions in human Hsp90 remain debated.
Purpose of the Study:
- To investigate the ATP-binding properties and ATPase activity of human Hsp90.
- To clarify the role of ATP in human Hsp90 function.
Main Methods:
- Investigated human Hsp90 ATP-binding using various methods.
- Utilized electron spin resonance (ESR) spectroscopy with spin-labeled ATP analogues.
Main Results:
- Human Hsp90 demonstrated no tight ATP binding.
- No detectable ATPase activity was observed for human Hsp90.
- Weak ATP binding (half-maximal at 400 microM) was detected using ESR spectroscopy.
Conclusions:
- Human Hsp90 does not appear to bind ATP tightly or possess significant ATPase activity.
- A weak, functionally enigmatic ATP interaction with human Hsp90 was identified.
- Further research is needed to elucidate the functional implications of weak ATP binding in Hsp90.