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Electron tunneling in Ru-modified His46Asp azurin. Coupling through the Cu ligands

Regan, J. J. and Di Bilio, A. J. and Winkler, J. R. and Richards, J. H. and Gray, H. B. (1998) Electron tunneling in Ru-modified His46Asp azurin. Coupling through the Cu ligands. Inorganica Chimica Acta, 275-276 (1-2). pp. 470-480. ISSN 0020-1693. doi:10.1016/S0020-1693(98)00066-8.

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We compare electron transfer (ET) rates in two chemically modified Pseudomonas aeruginosa azurins, to examine the role of the Cu ligands in the ET coupling. In both cases, ET proceeded from Cu^+ to a Ru(bpy)_2(im)^(3+) attached to the native His83. In this otherwise native system, the Cu^+ Ru^(3+) → Cu^(2+)Ru^(2+) rate is 1.2(1) × 10^6 s^(−1) (−ΔG° = 0.76 eV) (J.J. Regan, A.J. Di Bilio, R. Langen, L.K. Skov, J.R. Winkler, H.B. Gray and J.N. Onuchic, Chem. Biol., 2 (1995) 489 [1]; A.J. Di Bilio, M.G. Hill, N. Bonander, B.G. Karlsson, R.M. Villahermosa, B.G. Malmström, J.R. Winkler and H.B. Gray, J. Am. Chem. Soc., 119 (1997) 9921 [2]). In the His46Asp mutant (46 being one of the Cu ligands), the rate drops to 3.2(4) × 10^4 s^(−1) (−ΔG° ∼ 0.78 eV). Analysis suggests that this drop is primarily due to a disruption of electronic tube coupling, rather than to just a change in the driving force and/or reorganization energy of the reaction.

Item Type:Article
Related URLs:
URLURL TypeDescription
Winkler, J. R.0000-0002-4453-9716
Gray, H. B.0000-0002-7937-7876
Additional Information:© 1998 Elsevier Science S.A. Received 2 June 1997: accepted 26 September 1997. We thank Claire Slulter and Jack Mizoguchi for helpful discussions. This work was supported by the National Institutes of Health (DK19038 to H.B.G.; GM16424 to J.H.R.) and the Department of Energy (DE-FG03-96ER62219 to J.J.R.).
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG03-96ER62219
Subject Keywords:Electron transfer; Azurin; Copper ligands; Electron tunneling
Issue or Number:1-2
Record Number:CaltechAUTHORS:20150427-151804934
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Official Citation:J.J. Regan, A.J. Di Bilio, J.R. Winkler, J.H. Richards, H.B. Gray, Electron tunneling in Ru-modified His46Asp azurin. Coupling through the Cu ligands, Inorganica Chimica Acta, Volumes 275–276, 1 July 1998, Pages 470-480, ISSN 0020-1693, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:57025
Deposited By: Tony Diaz
Deposited On:27 Apr 2015 23:34
Last Modified:10 Nov 2021 21:06

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