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Electron Flow through Nitrotyrosinate in Pseudomonas aeruginosa Azurin

Warren, Jeffrey J. and Herrera, Nadia and Hill, Michael G. and Winkler, Jay R. and Gray, Harry B. (2013) Electron Flow through Nitrotyrosinate in Pseudomonas aeruginosa Azurin. Journal of the American Chemical Society, 135 (30). pp. 11151-11158. ISSN 0002-7863. PMCID PMC3839300. doi:10.1021/ja403734n.

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We have designed ruthenium-modified Pseudomonas aeruginosa azurins that incorporate 3-nitrotyrosine (NO_(2)YOH) between Ru(2,2′-bipyridine)_2(imidazole)(histidine) and Cu redox centers in electron transfer (ET) pathways. We investigated the structures and reactivities of three different systems: RuH107NO_(2)YOH109, RuH124NO_(2)YOH122, and RuH126NO_(2)YOH122. RuH107NO_(2)YOH109, unlabeled H124NO_(2)YOH122, and unlabeled H126NO_(2)YOH122 were structurally characterized. The pKa’s of NO_(2)YOH at positions 122 and 109 are 7.2 and 6.0, respectively. Reduction potentials of 3-nitrotyrosinate (NO_(2)YO^–)-modified azurins were estimated from cyclic and differential pulse voltammetry data: oxidation of NO_(2)YO^(–)122 occurs near 1.1 versus NHE; oxidation of NO_(2)YO^(–)109 is near 1.2 V. Our analysis of transient optical spectroscopic experiments indicates that hopping via NO_(2)YO^– enhances Cu^I oxidation rates over single-step ET by factors of 32 (RuH107NO_(2)YO^(–)109), 46 (RuH126NO_(2)YO^(–)122), and 13 (RuH124NO_(2)YO^(–)122).

Item Type:Article
Related URLs:
URLURL TypeDescription CentralArticle
Warren, Jeffrey J.0000-0002-1747-3029
Herrera, Nadia0000-0003-4157-9429
Winkler, Jay R.0000-0002-4453-9716
Gray, Harry B.0000-0002-7937-7876
Additional Information:© 2013 American Chemical Society. Received: April 15, 2013; published: July 16, 2013. Our work was supported by NIH (DK019038 to H.B.G. and J.R.W.; GM095037 to J.J.W.), an NSF Center for Chemical Innovation (Powering the Planet, CHE-0947829), and the Arnold and Mabel Beckman Foundation. We also acknowledge the Gordon and Betty Moore Foundation and the Sanofi- Aventis Bioengineering Research Program for their support of the Molecular Observatory facilities at the California Institute of Technology. X-ray crystallography data was collected at the Stanford Synchrotron Radiation Lightsource (SSRL), a Directorate of the SLAC National Accelerator Laboratory and an Office of Science User Facility operated for the U.S. Department of Energy, Office of Molecular Biology Program and Environmental Research, and by the National Institutes of Health, National Center for Research Resources, Biomedical Technology Program (P41RR001209), and the National Institute of General Medical Sciences.
Group:CCI Solar Fuels
Funding AgencyGrant Number
Arnold and Mabel Beckman FoundationUNSPECIFIED
Sanofi-Aventis Bioengineering Research ProgramUNSPECIFIED
Issue or Number:30
PubMed Central ID:PMC3839300
Record Number:CaltechAUTHORS:20131025-104510564
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Official Citation:Electron Flow through Nitrotyrosinate in Pseudomonas aeruginosa Azurin Jeffrey J. Warren, Nadia Herrera, Michael G. Hill, Jay R. Winkler, and Harry B. Gray Journal of the American Chemical Society 2013 135 (30), 11151-11158
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42069
Deposited On:28 Oct 2013 20:21
Last Modified:10 Nov 2021 04:37

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