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Electrochemistry of the Cu_A domain of Thermus thermophilus cytochrome ba _3

Immoos, Chad and Hill, Michael G. and Sanders, Donita and Fee, James A. and Slutter, Claire E. and Richards, John H. and Gray, Harry B. (1996) Electrochemistry of the Cu_A domain of Thermus thermophilus cytochrome ba _3. Journal of Biological Inorganic Chemistry, 1 (6). pp. 529-531. ISSN 0949-8257. doi:10.1007/s007750050088.

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The electrochemistry of a water-soluble fragment from the Cu_A domain of Thermus thermophilus cytochrome ba _3 has been investigated. At 25  °C, Cu_A exhibits a reversible reduction at a pyridine-4-aldehydesemicarbazone-modified gold electrode (0.1 M Tris, pH 8) with E° = 0.24 V vs NHE. Thermodynamic parameters for the [Cu(Cys)_2Cu]^(+/0) electrode reaction were determined by variable-temperature electrochemistry (ΔS°_(rc) = –5.4(12) eu, ΔS° = –21.0(12) eu, ΔH° = –11.9(4) kcal/mol;ΔG° = –5.6 (11) kcal/mol). The relatively small reaction entropy is consistent with a low reorganization energy for [Cu(Cys)_2Cu]^(+/0) electron transfer. An irreversible oxidation of [Cu(Cys)_2Cu]^+ at 1 V vs NHE confirms that the Cu^(II):Cu^(II) state of Cu_A is significantly destabilized relative to the Cu^(II) state of analogous blue-copper proteins.

Item Type:Article
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Gray, Harry B.0000-0002-7937-7876
Additional Information:© 1996 SBIC. Received: 3 June 1996; Accepted: 26 August 1996. This work was supported by the NIH (DK19038 to H.B.G.; GM35342 to J.A.F.; GM16424 to J.H.R.; GM07616 to C.E.S.), the Research Corporation (M.G.H.), the Camille and Henry Dreyfus Foundation (Faculty Start-up Grant to M.G.H.), and the NSF (DUE-9551647).
Funding AgencyGrant Number
Research CorporationUNSPECIFIED
Camille and Henry Dreyfus FoundationUNSPECIFIED
Subject Keywords:Cu-A domain; Thermus thermophilus; cytochrome ba(3); electrochemistry
Issue or Number:6
Record Number:CaltechAUTHORS:20150427-150735788
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Official Citation:Immoos, C., Hill, M. G., Sanders, D., Fee, J. A., Slutter, C. E., Richards, J. H., & Gray, H. B. (1996). Electrochemistry of the CuA domain of Thermus thermophilus cytochrome ba 3. JBIC Journal of Biological Inorganic Chemistry, 1(6), 529-531. doi: 10.1007/s007750050088
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57024
Deposited On:27 Apr 2015 23:31
Last Modified:10 Nov 2021 21:06

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