Reduction of Dioxygen Catalyzed by Pyrene-Wired Heme Domain Cytochrome P450 BM3 Electrodes

Udit, Andrew K.; Hill, Michael G.; Bittner, V. Garrett; Arnold, Frances H.; Gray, Harry B.

doi:10.1021/ja0466560

Cited by 58 publications

(55 citation statements)

References 15 publications

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“…2 and 3, the cathodic and anodic waves observed for SoxR are asymmetric: The oxidation wave is pronounced and substantially less broad compared with the reduction wave. In an ideal quasi-reversible system, the anodic to cathodic peak current ratio is unity (42,44), but this is certainly not the case for SoxR. We find an anodic to cathodic peak current ratio of 3.0 for SoxR in Fig.…”

Section: Soxr Binding Is Reported Through the Redmond Red Electrochemmentioning

confidence: 73%

DNA binding shifts the redox potential of the transcription factor SoxR

Gorodetsky

Dietrich²,

Lee

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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Electrochemistry measurements on DNA-modified electrodes are used to probe the effects of binding to DNA on the redox potential of SoxR, a transcription factor that contains a [2Fe-2S] cluster and is activated through oxidation. A DNA-bound potential of ؉200 mV versus NHE (normal hydrogen electrode) is found for SoxR isolated from Escherichia coli and Pseudomonas aeruginosa. This potential value corresponds to a dramatic shift of ؉490 mV versus values found in the absence of DNA. Using Redmond red as a covalently bound redox reporter affixed above the SoxR binding site, we also see, associated with SoxR binding, an attenuation in the Redmond red signal compared with that for Redmond red attached below the SoxR binding site. This observation is consistent with a SoxRbinding-induced structural distortion in the DNA base stack that inhibits DNA-mediated charge transport to the Redmond red probe. The dramatic shift in potential for DNA-bound SoxR compared with the free form is thus reconciled based on a high-energy conformational change in the SoxR-DNA complex. The substantial positive shift in potential for DNA-bound SoxR furthermore indicates that, in the reducing intracellular environment, DNA-bound SoxR is primarily in the reduced form; the activation of DNA-bound SoxR would then be limited to strong oxidants, making SoxR an effective sensor for oxidative stress. These results more generally underscore the importance of using DNA electrochemistry to determine DNA-bound potentials for redox-sensitive transcription factors because such binding can dramatically affect this key protein property.

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Section: Soxr Binding Is Reported Through the Redmond Red Electrochemmentioning

confidence: 73%

DNA binding shifts the redox potential of the transcription factor SoxR

Gorodetsky

Dietrich²,

Lee

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

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“…2, inset), correlating with electrochemical reduction of O 2 catalyzed by the heme of HMP (on bare Gr electroreduction of O 2 starts at potentials lower than À300 mV). This electrocatalytic reduction reaction is characteristic of the heme and heme proteins such as peroxidases and different type of globins (Ferapontova, 2004); it may be also observed with more complex heme-containing enzymes such as theophylline oxidase (Shipovskov and Ferapontova, 2008), cytochromes P450 (Uldt et al, 2004) and other types flavohemoglobins, e.g. from Ralstonia eutropha entrapped into the methylcellulose film (solely the heme redox transformation and no FAD signals were detected) (de Oliveira et al, 2007).…”

Section: Direct Electrochemistry Of Hmp Adsorbed On Graphitementioning

confidence: 85%

Direct electrochemistry and Os-polymer-mediated bioelectrocatalysis of NADH oxidation by Escherichia coli flavohemoglobin at graphiteelectrodes

Sosna

Bonamore²,

Gorton

et al. 2013

Biosensors and Bioelectronics

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a b s t r a c tEscherichia coli flavohemoglobin (HMP), which contains one heme and one FAD as prosthetic groups and is capable of reducing O 2 by its heme at the expense of NADH oxidized at its FAD site, was electrochemically studied at graphite (Gr) electrodes. Two signals were observed in voltammograms of HMP adsorbed on Gr, at À 477 and À 171 mV vs. Ag9AgCl, at pH 7.4, correlating with electrochemical responses from the FAD and heme domains, respectively. The electron transfer rate constant for ET reaction between FAD of HMP and the electrode was estimated to be 83 s. Direct bioelectrocatalytic oxidation of NADH by HMP was not observed, presumably due to impeded substrate access to HMP orientated on Gr through the FAD-domain and/or partial denaturation of HMP. Bioelectrocatalysis was achieved when HMP was wired to Gr by the Os redox polymers, with the onset of NADH oxidation at the formal potential of the particular Os complex (þ140 mV or À 195 mV). Apparent Michaelis constants K M app and j max were determined, showing bioelectrocatalytic efficiency of NADH oxidation by HMP exceeding the one earlier shown with diaphorase, which makes HMP very attractive as a component of bioanalytical and bioenergetic devices.

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“…A more elegant approach is to deliver the reducing equivalents directly from the cosubstrate to the oxidoreductases, thereby shortcutting the complicated natural electron transport chain. Ever since the pioneering work by Vilker and coworkers 14 , a range of direct regeneration approaches have been reported [15][16][17][18][19][20][21][22][23][24][25][26][27][28] .…”

mentioning

confidence: 99%

Photobiocatalytic chemistry of oxidoreductases using water as the electron donor

et al. 2014

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To date, water has been poorly studied as the sacrificial electron donor for biocatalytic redox reactions using isolated enzymes. Here we demonstrate that water can also be turned into a sacrificial electron donor to promote biocatalytic redox reactions. The thermodynamic driving force required for water oxidation is obtained from UV and visible light by means of simple titanium dioxide-based photocatalysts. The electrons liberated in this process are delivered to an oxidoreductase by simple flavin redox mediators. Overall, the feasibility of photobiocatalytic, water-driven bioredox reactions is demonstrated.

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Reduction of Dioxygen Catalyzed by Pyrene-Wired Heme Domain Cytochrome P450 BM3 Electrodes

Abstract: Cytochromes P450 (P450s) catalyze oxygenations of inert substrates under physiological conditions. 1 Exploiting this activity in vitro would be greatly facilitated if reductants other than NADPH could be found. While an electrode is perhaps the most attractive

Cited by 58 publications

References 15 publications

DNA binding shifts the redox potential of the transcription factor SoxR

DNA binding shifts the redox potential of the transcription factor SoxR

Direct electrochemistry and Os-polymer-mediated bioelectrocatalysis of NADH oxidation by Escherichia coli flavohemoglobin at graphiteelectrodes

Photobiocatalytic chemistry of oxidoreductases using water as the electron donor

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