Probing Electron Transfer in the Manganese‐Oxide‐Forming MnxEFG Protein Complex using Fourier Transformed AC Voltammetry: Understanding the Oxidative Priming Effect. Issue 6 (10th August 2017)

• Record Type: Journal Article
• Authors: Tao, Lizhi; Simonov, Alexandr N.; Romano, Christine A.; Butterfield, Cristina N.; Tebo, Bradley M.; Bond, Alan M.; Spiccia, Leone; Martin, Lisandra L.; Casey, William H.
• Is Part Of: ChemElectroChem. Volume 5:Issue 6(2018)
• Page Start: 872
• Page End: 876
• Publication Date: 2017-08-10
• Subjects: MnOx mineralisation -- electron transfer -- multicopper oxidase -- direct current protein voltammetry -- Fourier transformed alternating current voltammetry; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201700563
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: MnxG, a multicopper oxidase, is an enzyme from the marine Bacillus species, which produces manganese oxide minerals through the aerobic oxidation of dissolved Mn 2+ − a key process in global manganese geochemical cycling. When isolated in an active form as a part of the MnxEFG protein complex, the enzymatic activity of MnxG is substantially enhanced by mild oxidative priming. Herein, the mechanism for this effect is probed by using direct current (dc) and Fourier transformed alternating current (ac) voltammetric analysis of the MnxEFG complex and the catalytically inactive MnxEF subunit immobilised on a carbon electrode. Analysis of these ac voltammetric data reveals a significant enhancement in the rate of electron transfer in the Type 2 Cu sites upon oxidative priming of the enzyme, which is attributed to the improved catalytic activity of MnxG in the MnxEFG protein complex. Abstract : Held accountable : The MnxEFG protein complex is responsible for the formation of manganese‐oxide minerals in the environment. Mild oxidation of MnxEFG significantly enhances its enzymatic activity. The present study employs Fourier transformed ac voltammetry to demonstrate that this oxidative priming effect originates from facilitated internal electron transfer in the catalytic redox sites of the MnxEFG complex.