The movement of electrons in biomolecules and materials is central to many physical, chemical and biological processes as well as to electronics industry. The PI has found that protein filaments of common soil bacteria can move electrons similar to metallic systems. In this CAREER Project, the PI will identify the mechanism underlying this process that occurs over unprecedented distances. The results of the research could have applications in environmental, bioenergy, and microelectronics applications. The PI will integrate this research into a range of educational activities that will inspire and train the next-generation of interdisciplinary students to tackle challenging problems. The PI will draw from his own training in biophysics and structural and molecular biology as well as his experience in technology innovation and entrepreneurship to reach students at all levels. Specifically, the PI will first develop a new cross-disciplinary curriculum for undergraduate and graduate students to introduce key concepts at the intersection of physics, chemistry and biology that are not covered in traditional courses. Second, the PI will design hands-on laboratory activity on the science of bacteria-powered fuel cells, using the feedback from the teachers of New Haven Public School that primarily serve minority students. Third, the PI will disseminate molecular structures through a user-friendly software based on First Glance and Proteopedia. Fourth, the PI will increase participation of underrepresented and minority students into research by working closely with the Yale assistant dean of science education and the coordinator for local community and outreach events. Thus, this CAREER project will integrate highly interdisciplinary research at the interfaces of physics, chemistry and biology with a diverse educational program reaching students at all levels.
Electron transfer is fundamental to many life processes. Existing models of biological electron transfer rely primarily on tunneling and hopping mechanisms that are limited to few nanometers, and metallic conductivity has been considered impossible in proteins. These models cannot explain the remarkable capacity by bacteria to transport electrons over centimeters, 10,000 times their size. By introducing a new concept of delocalized conduction via closely stacked aromatic residues that can account for high conductivity in pili proteins, this CAREER project at Yale University proposal will expand the intellectual range of biophysics by building a mechanistic framework for extracellular electron transport. The overall goal of this project is to identify the mechanism of extracellular electron transfer in soil bacteria that occurs at rates and distances unprecedented in biology. Building on the discovery by the PI that pili protein filaments of Geobacter sulfurreducens show electrical properties similar to metallic polymers, this project aims to identify the structural, molecular and biophysical mechanism of metallic conductivity. First, the PI will identify crucial microscopic transport parameters in pili that led to electron delocalization. Second, the PI will visualize conformational changes in pili that drive electron transport. Third, the PI will obtain near atomic-resolution structures of pili using Cryo-EM. The success of this project could provide unprecedented new insights into the metabolism and communication of a diversity of microbial species that regulate our environment and are important for bioenergy and biofuel strategies. Engineering microbial interactions via conductive pili could potentially offer control over their physiology and ecology.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
