LiT: Molecular and Electronic Signatures of Pilus Nanowires

所有生命形式的决定性属性是通过电子传递过程产生能量，如呼吸作用、光合作用和元素循环，这些过程直接影响我们的气候和地球资源。作为地球动力学的主要贡献者，细菌为研究生物电子转移提供了独特的机会。这个团队研究了被称为Geobacter（来自拉丁语“来自地球的细菌”）的细菌是如何通过将电子转移到不溶性矿物质（如氧化铁）来产生生长能量的。这些细菌产生导电的毛发状细丝（或“毛”，来自拉丁语“头发”），与矿物质建立电子接触。虽然其他生物和物理系统的导电性是由相关金属或氧化还原活性有机化合物介导的，但毛杆菌的导电性是由一个单一的、小的、重复的肽亚基组装而成的。因此，这些细菌“纳米线”已经进化出一种独特的机制，通过蛋白质组装有效地传递电子，并作为研究基于蛋白质的电子转移的范例。该项目将使用多学科方法来研究毛杆菌如何在远远超出细胞范围的距离上转移电子。计算方法将用于模拟毛的结构和电子特性，以确定电子转移的潜在途径。该团队将使用遗传方法来设计具有预测电子转移缺陷的菌毛，这些缺陷将在生物和物理分析中进行分析。通过对生物电子转移及其在地球矿化过程和气候反馈中的作用的突破性科学知识的发展，这项工作的发现将产生重大而广泛的影响。这项工作也将提供关于生物分子组装的多步电子流的新基础知识，这可以用于纳米生物技术，生物能源以及有毒金属和放射性核素的生物修复方面的新应用。这项工作还将用于培养生物学、物理学和工程学交叉学科的研究生和本科生。该项目的一个重要教育组成部分是整合跨部门本科课程的研究以及新开发的跨学科生物电子学研究生课程。努力将包括(i)研究生生物电子学课程开发，（ii） k-12教师培训模块，以增加具有技术知识，教学技能和有效教学动机的教师/学者的全国库，以及（iii）项目团队积极，有针对性地从代表性不足的群体中招募学生。

The defining property of all life forms is the generation of energy through electron transfer processes such as respiration, photosynthesis, and elemental cycling, which directly influence our climate and the Earth's resources. As major contributors to our planet's dynamics, bacteria offer a unique opportunity to investigate biological electron transfer. This team has investigated how bacteria termed Geobacter (from the latin "bacteria from Earth") generate energy for growth through the transfer of electrons to insoluble minerals, such as iron oxides. These bacteria produce conductive hair-like filaments (or "pili", from the latin "hair") to establish electronic contact with the minerals. While the conductivity of other biological and physical systems is mediated by associated metals or redox-active organic compounds, the conductive properties of Geobacter pili result from the assembly of a single, small, repeating peptide subunit. Thus, these bacterial "nanowires" have evolved a unique mechanism(s) for efficient electron transport through a protein assembly and serve as a paradigm to study protein-based electron transfer. This project will use a multidisciplinary approach to investigate how Geobacter pili transfer electrons at distances that greatly exceed the reach of the cell. Computational methods will be employed to model the structure and electronic properties of the pili to identify potential pathways for electron transfer. The team will use genetic approaches to engineer pili with predicted defects in electron transfer, which will be assayed in biological and physical assays. Findings from this work will have a significant broader impact via development of groundbreaking scientific knowledge about biological electron transfer and its role in Earth's mineralization processes and climate feedbacks. The proposed work will also provide new fundamental knowledge about multistep electron flow through biomolecular assemblies, which can be harnessed for novel applications in nanobiotechnology, bioenergy, and bioremediation of toxic metals and radionuclides. The proposed work will also be used to train a new cohort of graduate and undergraduate students in interdisciplinary science at the interface of biology, physics, and engineering. A key educational component of this project is the integration of the research in interdepartmental undergraduate courses as well as in a newly developed interdisciplinary graduate program in bioelectronics. Efforts will include (i) curricular development in bioelectronics for graduate students, (ii) a k-12 teacher-training module to increase the national pool of teacher/scholars with the technical knowledge, pedagogical skills, and motivation to effectively teach in this area, and (iii) an aggressive, targeted recruitment effort of students from underrepresented groups by the project's team.