Effect of Hydrogen Peroxide on the Activity and Structure of Escherichia coli Chaperone GroEL

F. Wang¹, W.-B. Ou¹, S. Li¹, and H.-M. Zhou^1,2*

¹Department of Biological Science and Biotechnology, Tsinghua University, Beijing, 100084 P. R. China; fax: (8610) 627-85505; E-mail: zhm-dbs@mail.tsinghua.edu.cn

²Protein Science Laboratory of the Ministry of Education, School of Life Science and Engineering, Tsinghua University, Beijing, 100084 P. R. China

^* To whom correspondence should be addressed.

Received March 16, 2001

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Chaperone GroEL was treated with different concentrations of hydrogen peroxide. The conformational states of GroEL were monitored by protein intrinsic fluorescence, 8-anilino-1-naphthalene sulfonate fluorescence, and far-UV CD measurements. The results show that GroEL has unusual ability to resist oxidative stress. GroEL kept its quaternary structure and activity even when treated with 10 mM hydrogen peroxide. Two fragments were formed when GroEL was treated with high concentrations of hydrogen peroxide (more than 20 mM). It is suggested that GroEL, as a molecular chaperone, is related to oxidative process in vivo.

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KEY WORDS: GroEL, hydrogen peroxide, structure, activity

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