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Dehydration in the Folding of Reduced Cytochrome c Revealed by the Electron-Transfer-Triggered Folding under High Pressure

Kimura, Tetsunari and Sakamoto, Koichi and Morishima, Isao and Ishimori, Koichiro (2006) Dehydration in the Folding of Reduced Cytochrome c Revealed by the Electron-Transfer-Triggered Folding under High Pressure. Journal of the American Chemical Society, 128 (3). pp. 670-671. ISSN 0002-7863. https://resolver.caltech.edu/CaltechAUTHORS:20170421-104937310

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Abstract

We determined the activation volume associated with protein folding of reduced cytochrome c from the collapsed intermediate to the native state. The folding rate was followed by a change in the absorption (420 nm) at various pressures between 0.1 and 200 MPa and at various concentrations of denaturant (guanidine hydrochloride) between 3.2 and 4.0 M. Dependence of the folding rate on both these factors revealed that the activation volume at ambient pressure in the absence of denaturant is negative (ΔV_f^(0⧧) = −14 (±8) cm^3·mol^(-1)). Such a negative activation volume can be accounted for by a decrease in volume resulting from the dehydration of hydrophobic groups, primarily the heme group. Dehydration, which increases the entropy of the protein system, compensates for a decrease in the entropy accompanying the formation of the more compact and ordered transition state. We, therefore, propose that the positive change in the activation entropy for the folding reaction is due to the dehydration of hydrophobic groups. Furthermore, dehydration entropically promotes the protein folding reaction.


Item Type:Article
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http://dx.doi.org/10.1021/ja055084wDOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja055084wPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/ja055084wPublisherSupporting Information
Additional Information:© 2006 American Chemical Society. Received July 27, 2005. Publication Date (Web): December 22, 2005. This work was supported by Grants-in-Aids for Scientific Research from the Ministry of Education, Science, Sports, and Culture of Japan to K.I. (16041226). T.K. was supported by a Research Fellowship of the Japan Society for the Promotion of Science for Young Scientists.
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Funding AgencyGrant Number
Ministry of Education, Science, Sports, and Culture (MEXT)16041226
Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Issue or Number:3
Record Number:CaltechAUTHORS:20170421-104937310
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170421-104937310
Official Citation:Dehydration in the Folding of Reduced Cytochrome c Revealed by the Electron-Transfer-Triggered Folding under High Pressure Tetsunari Kimura, Koichi Sakamoto, Isao Morishima, and Koichiro Ishimori Journal of the American Chemical Society 2006 128 (3), 670-671 DOI: 10.1021/ja055084w
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76816
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:21 Apr 2017 18:14
Last Modified:03 Oct 2019 17:50

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