Effect of Ionic Strength on the Rate of Extracellular Electron Transport in Shewanella oneidensis MR‐1 through Bound‐Flavin Semiquinones. Issue 11 (5th September 2014)

• Record Type: Journal Article
• Authors: Kalathil, Shafeer; Hashimoto, Kazuhito; Okamoto, Akihiro
• Is Part Of: ChemElectroChem. Volume 1:Issue 11(2014)
• Page Start: 1840
• Page End: 1843
• Publication Date: 2014-09-05
• Subjects: Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201402195
• Languages: English
• ISSNs: 2196-0216

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>Cell‐secreted flavin binds to outer‐membrane <italic>c</italic>‐type cytochromes (OM <italic>c</italic>‐Cyts) as a redox cofactor in <italic>Shewanella oneidensis</italic> MR‐1, generating a semiquinone (Sq) state to enhance the rate of extracellular electron‐transport (EET) process by several orders of magnitude. Here, as ionic strength (<italic>I</italic>_s) is a major factor in stabilizing bound Sq in flavoproteins, we examined the influence of <italic>I</italic>_s on the flavin affinity in OM <italic>c‐</italic>Cyts to promote Sq formation for enhancing the rate of the EET process. Estimated dissociation constants showed that an increase in <italic>I</italic>_s induces threefold higher Sq formation in OM <italic>c‐</italic>Cyts. However, the higher <italic>I</italic>_s neither resulted in the larger current production nor current enhancement by flavin addition. Strong <italic>I</italic>_s dependency for the redox potential of heme centers in OM <italic>c</italic>‐Cyts suggests that <italic>I</italic>_s not only controls the stability of Sq, but also alters coupling constants among redox centers in OM <italic>c</italic>‐Cyts through structural changes.</p> </abstract>