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Tryptophan-Accelerated Electron Flow Through Proteins

Shih, Crystal and Museth, Anna Katrine and Abrahamsson, Malin and Blanco-Rodríguez, Ana María and Di Bilio, Angel J. and Sudhamsu, Jawahar and Crane, Brian R. and Ronayne, Kate L. and Towrie, Mike and Vlček, Antonín, Jr. and Richards, John H. and Winkler, Jay R. and Gray, Harry B. (2008) Tryptophan-Accelerated Electron Flow Through Proteins. Science, 320 (5884). pp. 1760-1762. ISSN 0036-8075. doi:10.1126/science.1158241.

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Energy flow in biological structures often requires submillisecond charge transport over long molecular distances. Kinetics modeling suggests that charge-transfer rates can be greatly enhanced by multistep electron tunneling in which redox-active amino acid side chains act as intermediate donors or acceptors. We report transient optical and infrared spectroscopic experiments that quantify the extent to which an intervening tryptophan residue can facilitate electron transfer between distant metal redox centers in a mutant Pseudomonas aeruginosa azurin. CuI oxidation by a photoexcited ReI-diimine at position 124 on a histidine(124)-glycine(123)-tryptophan(122)-methionine(121) β strand occurs in a few nanoseconds, fully two orders of magnitude faster than documented for single-step electron tunneling at a 19 angstrom donor-acceptor distance.

Item Type:Article
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URLURL TypeDescription Material
Winkler, Jay R.0000-0002-4453-9716
Gray, Harry B.0000-0002-7937-7876
Additional Information:© 2008 American Association for the Advancement of Science. Received 24 March 2008; accepted 21 May 2008. We thank C. Grădinaru, B. Leigh, and J. Miller for assistance in the early stages of this work. Supported by NIH (DK19038 to H.B.G.); NSF (CHE-0749997 to B.R.C., and CHE-0533150 to H.B.G. and J.R.W.); the Foundation BLANCEFLOR Boncompagni-Ludovisi, née Bildt; STINT, the Swedish Foundation for International Cooperation in Research and Higher Education (MLAA); the Engineering and Physical Sciences Research Council; Queen Mary, University of London; and the Science and Technology Facilities Council (CMSD43). The coordinates of the ReI(CO)3 (dmp)(H124)|(W122)|AzCuII crystal structure have been deposited in the Protein Data Bank (accession number 2I7O).
Funding AgencyGrant Number
Foundation BLANCEFLOR Boncompagni-LudovisiUNSPECIFIED
Swedish Foundation for International Cooperation in Research and Higher Education (STINT)UNSPECIFIED
Engineering and Physical Sciences Research Council (EPSRC)UNSPECIFIED
Queen Mary, University of LondonUNSPECIFIED
Science and Technology Facilities Council (STFC)CMSD43
Issue or Number:5884
Record Number:CaltechAUTHORS:20141118-091949973
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51885
Deposited By: Tony Diaz
Deposited On:18 Nov 2014 18:08
Last Modified:10 Nov 2021 19:17

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