Department of Microbiology and Molecular Genetics, Michigan State University, 567 Wilson Rd., Rm. 6190, East Lansing, MI, 48824, USA.
Microb Biotechnol. 2018 Nov;11(6):979-994. doi: 10.1111/1751-7915.13280. Epub 2018 May 27.
The reduction of iron oxide minerals and uranium in model metal reducers in the genus Geobacter is mediated by conductive pili composed primarily of a structurally divergent pilin peptide that is otherwise recognized, processed and assembled in the inner membrane by a conserved Type IVa pilus apparatus. Electronic coupling among the peptides is promoted upon assembly, allowing the discharge of respiratory electrons at rates that greatly exceed the rates of cellular respiration. Harnessing the unique properties of these conductive appendages and their peptide building blocks in metal bioremediation will require understanding of how the pilins assemble to form a protein nanowire with specialized sites for metal immobilization. Also important are insights into how cells assemble the pili to make an electroactive matrix and grow on electrodes as biofilms that harvest electrical currents from the oxidation of waste organic substrates. Genetic engineering shows promise to modulate the properties of the peptide building blocks, protein nanowires and current-harvesting biofilms for various applications. This minireview discusses what is known about the pilus material properties and reactions they catalyse and how this information can be harnessed in nanotechnology, bioremediation and bioenergy applications.
在模型金属还原剂属的杆状菌属中，氧化铁矿物和铀的减少是由主要由结构上不同的菌毛肽组成的导电菌毛介导的，该菌毛肽在内在膜中通过保守的 IVa 型菌毛装置被识别、加工和组装。在组装过程中，肽之间的电子偶联得到促进，从而允许以大大超过细胞呼吸速率的速率排出呼吸电子。利用这些导电附属物及其肽构建块在金属生物修复中的独特性质，需要了解菌毛如何组装成具有金属固定化专用位点的蛋白质纳米线。同样重要的是，要深入了解细胞如何组装菌毛以形成具有电活性基质的生物膜，并作为生物膜在电极上生长，从废有机基质的氧化中获取电流。遗传工程显示出有希望调节肽构建块、蛋白质纳米线和电流收集生物膜的特性，以用于各种应用。这篇小综述讨论了关于菌毛材料特性及其催化的反应的已知信息，以及如何将这些信息应用于纳米技术、生物修复和生物能源应用。
