Understanding and using microbial conductive nanowires

摘要 电子沿硫还原菌蛋白细丝网络的长距离(&gt；10μm)传输，称为 微生物纳米线被用来解释一系列全球重要的氧化还原现象。这个 这些纳米线卓越的电子传导能力引起了人们对医学领域的极大兴趣 应用空间，例如用于构建生物兼容材料和生物传感器。十多年来，G. 硫还原菌纳米线被认为是IV型细菌菌毛，由许多间接遗传和 生化观察。最近，我们发现这些导电纳米线不是由IV型菌毛制成的。 相反，这些结构是一种聚合的多血红素c型细胞色素，omcs，从未被 以前的特点。OMCs细丝模型与OMCs在地杆菌中的已知作用是一致的 呼吸作用，但我们对细胞色素附属物的了解仍然非常有限。这项研究旨在解决 呼吸原核生物细胞色素细丝的基本科学问题及其应用 普通医学领域的新发现。具体地说，我将：a)鉴定和表征新的细胞色素 细菌和古生菌菌株中的细丝，通过生物信息学算法，然后进行显微镜验证。 B)然后用高分辨低温电子研究这些细丝的传导机制。 显微镜(低温电子显微镜)和电导率测量。C)最后，基于对细胞色素的这些新见解 长丝，我将为自组装的导电纳米线创造一个新的设计。这些纳米线可能是 直接来自新的细胞色素细丝或可能含有基于肽/蛋白质的自组装支架 核外表面附着可溶的细胞色素。这一结果将促进我们对 细胞色素纳米线，以及产生可用于许多领域的自组装纳米线支架 未来的生物医学应用。

Abstract Long-range (>10 μm) transport of electrons along networks of G. sulfurreducens protein filaments, known as microbial nanowires, has been invoked to explain a wide range of globally important redox phenomena. The remarkable electronic conduction capability of those nanowires has sparked a great deal of interest in the medical application space, such as for building biocompatible materials and biosensor. For more than a decade, G. sulfurreducens nanowires were thought to be bacterial type IV pili, supported by many indirect genetic and biochemical observations. Recently we showed that these conductive nanowires are not made of type IV pilins. Instead, these structures are a polymerized multi-heme c-type cytochrome, OmcS, which have never been characterized before. The OmcS filament model is consistent with the known roles of OmcS in Geobacter respiration, but our knowledge of cytochrome appendages is still very limited. This study aims at addressing fundamental scientific questions about cytochrome filaments in respiring prokaryotes as well as applying our discoveries into the general medical field. Specifically, I will: A) identify and characterize novel cytochrome filaments in bacterial and archaeal strains, through bioinformatics algorithms followed by microscopic validation. B) Then I will study the conduction mechanism of these filaments by high resolution cryogenic electron microscopy (cryo-EM) and conductivity measurement. C) Finally, based on these new insights into cytochrome filaments, I will create a novel design for a self-assembled conductive nanowire. These nanowires may be derived directly from a novel cytochrome filament or may contain a peptide/protein based self-assembled scaffold core with soluble cytochromes appended to the outer surface. The results will advance our understanding of cytochrome nanowires, as well as generating self-assembling nanowire scaffolds that may be used in many future biomedical applications.