Ramach Ulrich, Andersson Jakob, Schöfbeck Rosmarie, Valtiner Markus
Institute for Applied Physics, Vienna University of Technology, 1090 Vienna, Austria.
Competence Center for Electrochemical, Surface Technologies, CEST, 2700 Wiener Neustadt, Austria.
iScience. 2022 Dec 30;26(2):105918. doi: 10.1016/j.isci.2022.105918. eCollection 2023 Feb 17.
The light-driven reactions of photosynthesis as well as the mitochondrial power supply are located in specialized membranes containing a high fraction of redox-active lipids. In-plane charge transfer along such cell membranes is currently thought to be facilitated by the diffusion of redox lipids and proteins. Using a membrane on-a-chip setup, we show here that redox-active model membranes can sustain surprisingly high currents (mA) in-plane at distances of 25 μm. We also show the same phenomenon in free-standing monolayers at the air-water interface once the film is compressed such that the distance between redox centers is below 1 nm. Our data suggest that charge transfer within cell walls hosting electron transfer chains could be enabled by the coupling of redox-lipids via simultaneous electron and proton in-plane hopping, similar to conductive polymers. This has major implications for our understanding of the role of lipid membranes, suggesting that Q-lipid-containing membranes may be essential for evolving the complex redox machineries of life.
光合作用的光驱动反应以及线粒体供能过程都位于含有高比例氧化还原活性脂质的特殊膜中。目前认为，沿此类细胞膜的面内电荷转移是由氧化还原脂质和蛋白质的扩散促进的。通过芯片上的膜装置，我们在此表明，氧化还原活性模型膜在25μm的距离内能够在面内维持惊人的高电流（毫安）。我们还表明，一旦在空气 - 水界面处的独立单层膜被压缩，使得氧化还原中心之间的距离低于1nm，也会出现同样的现象。我们的数据表明，承载电子传递链的细胞壁内的电荷转移可能是通过氧化还原脂质通过电子和质子同时面内跳跃的耦合来实现的，类似于导电聚合物。这对我们理解脂质膜的作用具有重要意义，表明含Q脂质的膜对于生命复杂氧化还原机制的进化可能至关重要。
