Multiple hops move electrons from bacteria to rocks.
Multiple hops move electrons from bacteria to rocks.
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多次跳跃将电子从细菌转移到岩石。
DOI：
10.1073/pnas.2115620118
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发表时间：
2021
影响因子：
11.1
通讯作者：
Beratan,DavidN
中科院分区：
文献类型：
--
作者：
Beratan,DavidN
生物能量学的核心原理是光子给分子中的电子提供能量，这些电子推动质子，质子浓度梯度形成化学键。在电子和原子的层面上，对其工作原理的理解是难以捉摸的，尤其是在那些生活在生存边缘的生物体中。细菌或细菌电缆是如何在微米到厘米之间的源和汇之间移动电子的？van Wonderen等人在《美国国家科学院院刊》（PNAS）上表明，在使用矿物质作为终端电子受体的“岩石呼吸”细菌中，血红素到血红素的电子跳跃传输机制使电子能够通过细菌细胞包膜出口(1)。一些生物氧化还原反应可以在低温下进行的惊人发现(2)推动了振动耦合电子隧穿理论的发展(3)。理论预测，电子转移（ET）反应可以在几个纳米的时间尺度上发生，短至毫秒，支持电子隧穿可以加强分子生物能量学的概念。金属标记蛋白质的实验研究（4,5）和隧道通路理论(6)为蛋白质介导的ET的描述带来了原子细节。这些研究表明，电子隧道是通过通过键和通过空间相互作用实现的，这是由折叠蛋白质的分子结构及其辅因子决定的。电子通过细胞外附属物（细菌纳米线）在微米长度尺度上的传输与单步电子隧穿理论不一致(7)。电子是如何在几乎没有热力学驱动力的情况下，在生物相关的时间尺度上走出细胞包膜并传播数微米的？纳米线的建模要求电子隧穿必须发生在近范德华（vdW）接触的辅因子之间，以解释测量的电流（7,8）。在
The central dogma of bioenergetics is that photons energize electrons in molecules, those electrons push protons, and proton concentration gradients forge chemical bonds. An understanding of how this works—at the level of electrons and atoms—is elusive, especially in organisms that live life on the edge of survival. How do bacteria or bacterial cables move electrons between sources and sinks separated by micrometers to centimeters? In PNAS, van Wonderen et al. show that a heme-to-heme electron hopping transport mechanism enables the egress of electrons through the bacterial cell envelope in “rock-breathing” bacteria that use minerals as their terminal electron acceptors (1). The stunning discovery that some biological redox reactions can proceed at cryogenic temperatures (2) motivated the development of vibronically coupled electron-tunneling theories (3). Theory predicted that electron transfer (ET) reactions could occur over several nanometers on time scales as short as milliseconds, supporting the notion that electron tunneling could undergird molecular bioenergetics. Experimental studies of metal-labeled proteins (4, 5) and tunneling pathway theories (6) brought atomistic detail to the description of protein-mediated ET. These studies indicate that electron tunneling is enabled by both through-bond and through-space interactions, dictated by the molecular structure of the folded protein and by its cofactors.Electron transport through extracellular appendages (bacterial nanowires) on micrometer length scales is not reconciled by the theory of single-step electron tunneling (7). How can electrons exit the cell envelope and propagate for micrometers on biologically relevant timescales with little thermodynamic driving force? Modeling of nanowires requires that electron tunneling would have to occur between cofactors in near van der Waals (vdW) contact to explain the measured currents (7, 8). In