Grebenko Artem, Dremov Vyacheslav, Barzilovich Petr, Bubis Anton, Sidoruk Konstantin, Voeikova Tatiyana, Gagkaeva Zarina, Chernov Timur, Korostylev Evgeny, Gorshunov Boris, Motovilov Konstantin
Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation.
Institute of Solid State Physics (RAS), Academician Osipyana street 2, Chernogolovka, Russia.
PLoS One. 2018 Jan 19;13(1):e0191289. doi: 10.1371/journal.pone.0191289. eCollection 2018.
For decades respiratory chain and photosystems were the main firing field of the studies devoted to mechanisms of electron transfer in proteins. The concept of conjugated lateral electron and transverse proton transport during cellular respiration and photosynthesis, which was formulated in the beginning of 1960-s, has been confirmed by thousands of experiments. However, charge transfer in recently discovered bacterial nanofilaments produced by various electrogenic bacteria is regarded currently outside of electron and proton conjugation concept. Here we report the new study of charge transfer within nanofilaments produced by Shewanella oneidensis MR-1 conducted in atmosphere of different relative humidity (RH). We utilize impedance spectroscopy and DC (direct current) transport measurements to find out the peculiarities of conductivity and Raman spectroscopy to analyze the nanofilaments' composition. Data analysis demonstrates that apparent conductivity of nanofilaments has crucial sensitivity to humidity and contains several components including one with unusual behavior which we assign to electron transport. We demonstrate that in the case of Shewanella oneidensis MR-1 charge transfer within these objects is strongly mediated by water. Basing on current data analysis of conductivity we conclude that the studied filaments of Shewanella oneidensis MR-1 are capable of hybrid (conjugated) electron and ion conductivity.
几十年来，呼吸链和光系统一直是致力于蛋白质中电子转移机制研究的主要领域。20世纪60年代初提出的细胞呼吸和光合作用过程中电子侧向共轭和质子横向传输的概念，已被数千次实验所证实。然而，目前认为各种产电细菌产生的细菌纳米丝中的电荷转移超出了电子和质子共轭的概念。在此，我们报告了在不同相对湿度（RH）环境下对希瓦氏菌MR-1产生的纳米丝内电荷转移的新研究。我们利用阻抗谱和直流（direct current）传输测量来找出导电性的特性，并利用拉曼光谱分析纳米丝的组成。数据分析表明，纳米丝的表观导电性对湿度具有至关重要的敏感性，并且包含几个成分，其中一个具有不寻常的行为，我们将其归因于电子传输。我们证明，对于希瓦氏菌MR-1，这些物体内的电荷转移强烈地由水介导。基于目前对导电性的数据分析，我们得出结论，所研究的希瓦氏菌MR-1的细丝能够进行混合（共轭）电子和离子传导。
