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Mimicking protein-protein electron transfer: voltammetry of Pseudomonas aeruginosa azurin and the Thermus thermophilus Cu_A domain at ω-derivatized self-assembled-monolayer gold electrodes

Fujita, Kyoko and Nakamura, Nobufumi and Ohno, Hiroyuki and Leigh, Brian S. and Niki, Katsumi and Gray, Harry B. and Richards, John H. (2004) Mimicking protein-protein electron transfer: voltammetry of Pseudomonas aeruginosa azurin and the Thermus thermophilus Cu_A domain at ω-derivatized self-assembled-monolayer gold electrodes. Journal of the American Chemical Society, 126 (43). pp. 13954-61. ISSN 0002-7863. doi:10.1021/ja047875o. https://resolver.caltech.edu/CaltechAUTHORS:20150424-154505770

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Abstract

Well-defined voltammetric responses of redox proteins with acidic-to-neutral pI values have been obtained on pure alkanethiol as well as on mixed self-assembled-monolayer (SAM) ω-derivatized alkanethiol/gold bead electrodes. Both azurin (P. aeruginosa) (pI = 5.6) and subunit II (CuA domain) of ba_3-type cytochrome c oxidase (T. thermophilus) (pI = 6.0) exhibit optimal voltammetric responses on 1:1 mixtures of [H_3C(CH_2)_nSH + HO(CH_2)_nSH] SAMs. The electron transfer (ET) rate vs distance behavior of azurin and CuA is independent of the ω-derivatized alkanethiol SAM headgroups. Strikingly, only wild-type azurin and mutants containing Trp48 give voltammetric responses:  based on modeling, we suggest that electronic coupling with the SAM headgroup (H_3C− and/or HO−) occurs at the Asn47 side chain carbonyl oxygen and that an Asn47-Cys112 hydrogen bond promotes intramolecular ET to the copper. Inspection of models also indicates that the CuA domain of ba3-type cytochrome c oxidase is coupled to the SAM headgroup (H_3C− and/or HO−) near the main chain carbonyl oxygen of Cys153 and that Phe88 (analogous to Trp143 in subunit II of cytochrome c oxidase from R. sphaeroides) is not involved in the dominant tunneling pathway. Our work suggests that hydrogen bonds from hydroxyl or other proton-donor groups to carbonyl oxygens potentially can facilitate intermolecular ET between physiological redox partners.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/ja047875oDOIArticle
http://pubs.acs.org/doi/abs/10.1021/ja047875oPublisherArticle
ORCID:
AuthorORCID
Gray, Harry B.0000-0002-7937-7876
Additional Information:© 2004 American Chemical Society. Received April 13, 2004. Publication Date (Web): October 7, 2004. Dedicated to the memory of Katsumi Niki, who passed away on 4 May 2004, a few weeks after our manuscript was submitted. This work was supported by NIH DK19038, NSF, and the Arnold and Mabel Beckman Foundation. K.F. thanks the Japan Society for Promotion of Science (Research Fellowship for Young Scientists) for support; B.S.L. acknowledges the Parsons Foundation for a graduate fellowship.
Funders:
Funding AgencyGrant Number
NIHDK19038
NSFUNSPECIFIED
Arnold and Mabel Beckman FoundationUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Parsons FoundationUNSPECIFIED
Issue or Number:43
DOI:10.1021/ja047875o
Record Number:CaltechAUTHORS:20150424-154505770
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150424-154505770
Official Citation:Mimicking Protein−Protein Electron Transfer:  Voltammetry of Pseudomonas aeruginosa Azurin and the Thermus thermophilus CuA Domain at ω-Derivatized Self-Assembled-Monolayer Gold Electrodes Kyoko Fujita, Nobufumi Nakamura, Hiroyuki Ohno, Brian S. Leigh, Katsumi Niki, Harry B. Gray, and John H. Richards Journal of the American Chemical Society 2004 126 (43), 13954-13961 DOI: 10.1021/ja047875o
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:56980
Collection:CaltechAUTHORS
Deposited By: George Porter
Deposited On:24 Apr 2015 23:00
Last Modified:10 Nov 2021 21:06

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