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X-ray absorption edge studies on oxidized and reduced cytochrome c oxidase

Hu, Valerie W. and Chan, Sunney I. and Brown, George S. (1977) X-ray absorption edge studies on oxidized and reduced cytochrome c oxidase. Proceedings of the National Academy of Sciences of the United States of America, 74 (9). pp. 3821-3825. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:HUVpnas77

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Abstract

The x-ray absorption edge spectra of the Cu and Fe centers in oxidized and reduced cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase; EC 1.9.3.1) have been obtained using synchrotron radiation from the SPEAR storage ring at the Stanford Linear Accelerator Center. In addition, oxidized and reduced plastocyanin as well as a number of model copper compounds in various oxidation states were also examined. A comparison of the absorption edge fine structure of cytochrome oxidase with those of the models indicates that one of the two coppers in the oxidized protein is in the + 1 oxidation state. Upon reduction of the protein with dithionite, the second copper becomes Cu(I). The shift in the Fe K-edge of cytochrome oxidase upon reduction is small (about 2 eV or 3 x 10(-19) J) and is comparable to that previously observed for the reduction of the heme iron of cytochrome c.


Item Type:Article
Additional Information:Copyright © 1977 by the National Academy of Sciences. Communicated by Harry B. Gray, June 23, 1977. This research would not have been possible without the overwhelming generosity of several people. Drs. Tsoo E. King, Chang-An Yu, and Linda Yu of the State University of New York at Albany generously supplied us with purified and concentrated cytochrome c oxidase. Drs. Robert Gagne and Harry Gray and Mr. Dave Dooley provided us with many of the model compounds referred to in this paper. Dr. William Blumberg made available to us his data on several model compounds prior to publication. To all these individuals, we are extremely grateful. We would also like to thank Drs. W. E. Blumberg, R. Gamble, H. B. Gray, and R. G. Shulman for many stimulating discussions and their continued interest and encouragement throughout this work. This work was partially supported by Grant 22432 from the National Institute of General Medical Sciences, U.S. Public Health Service, and by National Science Foundation Grant DMR73-07692, in cooperation with the Stanford Linear Accelerator Center and the U.S. Energy Research and Development Administration. V.W.H. is a recipient of a National Institutes of Health predoctoral traineeship. This is Contribution no. 5551 from the Division of Chemistry and Chemical Engineering. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.
Subject Keywords:copper oxidation states; absorption edge fine structure; model copper compounds; core electronic transitions; synchrotron radiation
Record Number:CaltechAUTHORS:HUVpnas77
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:HUVpnas77
Alternative URL:http://www.pnas.org/cgi/content/abstract/74/9/3821
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1493
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:23 Jan 2006
Last Modified:26 Dec 2012 08:44

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