LiT: Molecular and Electronic Signatures of Pilus Nanowires

所有生命形式的定义属性是通过呼吸、光合作用和元素循环等电子传递过程产生能量，这些过程直接影响我们的气候和地球资源。作为地球动态的主要贡献者，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Gebacter的细菌(源自拉丁语“来自地球的细菌”)是如何通过将电子转移到不溶矿物(如氧化铁)而产生生长所需的能量的。这些细菌产生像毛发一样的导电细丝(或“菌毛”，源自拉丁语“头发”)，以建立与矿物质的电子联系。虽然其他生物和物理系统的导电性是由伴生金属或氧化还原活性有机化合物介导的，但菌毛地杆菌的导电性是由单个、小的、重复的多肽亚基组装而成的。因此，这些细菌“纳米线”已经进化出一种独特的机制(S)，用于通过蛋白质组装进行有效的电子转移，并作为研究基于蛋白质的电子转移的范例。这个项目将使用多学科的方法来研究地杆菌菌毛是如何在远远超出细胞接触范围的距离内转移电子的。将使用计算方法对PILI的结构和电子性质进行建模，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的电子转移缺陷的菌毛，这将在生物和物理测试中进行分析。这项工作的结果将通过发展有关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开创性科学知识而产生重大而广泛的影响。这项拟议的工作还将提供有关生物分子组件中多步电子流动的新的基础知识，这些知识可用于纳米生物技术、生物能源以及有毒金属和放射性核素的生物修复。拟议的工作还将用于培训一批新的研究生和本科生，他们在生物学、物理学和工程学的交界处从事跨学科科学研究。这个项目的一个关键教育组成部分是将研究整合到跨系本科课程以及新开发的生物电子学跨学科研究生课程中。将努力包括：(I)为研究生开发生物电子学课程；(Ii)K-12教师培训模块，以增加国家教师/学者库中的技术知识、教学技能和在该领域有效教学的动力；以及(Iii)积极、有针对性地从项目团队代表性不足的群体中招聘学生。

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.