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Unfolding four-helix bundles

Gray, Harry B. and Winkler, Jay R. and Kozak, John J. (2011) Unfolding four-helix bundles. Molecular Physics, 109 (6). pp. 905-916. ISSN 0026-8976. doi:10.1080/00268976.2011.558855.

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A geometrical model has been developed to describe the early stages of unfolding of cytochromes c' and c-b_(562). Calculations are based on a step-wise extension of the polypeptide chain subject to the constraint that the spatial relationship among the residues of each triplet is fixed by the native-state crystallographic data. The response of each protein to these structural perturbations allows the evolution of each of the four helices in these two proteins to be differentiated. It is found that the two external helices in c' unfold before its two internal helices, whereas exactly the opposite behaviour is demonstrated by c-b_(562). Each of these cytochromes has an extended, internal, non-helical ("turning") region that initially lags behind the most labile helix but then, at a certain stage (identified for each cytochrome), unravels before any of the four helices present in the native structure. It is believed that these predictions will be useful in guiding future experimental studies on the unfolding of these two cytochromes.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Gray, Harry B.0000-0002-7937-7876
Winkler, Jay R.0000-0002-4453-9716
Additional Information:© 2011 Taylor & Francis. Received 25 October 2010; final version received 24 January 2011.
Subject Keywords:cytochrome four-helix bundles; proteins; denaturation; steric constrains
Issue or Number:6
Record Number:CaltechAUTHORS:20110414-085410464
Persistent URL:
Official Citation:Unfolding four-helix bundles Harry B. Gray; Jay R. Winkler; John J. Kozak Pages 905 - 916
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:23318
Deposited By: Ruth Sustaita
Deposited On:14 Apr 2011 23:10
Last Modified:09 Nov 2021 16:13

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