Microbial Wires Could Generate Energy or Immobilize Environmental Contaminants
A team of researchers from the University of East Anglia and Pacific Northwest National Laboratory have determined, for the first time, the molecular structure of the proteins that enable the bacterium Shewanella oneidensis to transfer an electrical charge. The bacteria survive in oxygen-free environments by constructing small wires that extend through the cell wall and contact minerals—a process called iron respiration or “breathing rocks.” Proteins within these wires pass electrons outward to create an electrical charge. Using resources at the Environmental Molecular Sciences Laboratory (EMSL), including X-ray crystallography, the scientists gained new insights about how these proteins work together to move electrons from the inside to the outside of a cell. Identifying the molecular structure of these proteins is a key step toward potentially using microbes as a source of electricity; for example, by connecting them to electrodes to create microbial fuel cells. Because the bacteria also trap and transform the minerals they contact, the new information could advance the development of microbe-based agents for use in environmental remediation such as cleaning up legacy radioactive waste. EMSL is a Department of Energy national scientific user facility.
Clarke, T. A., M. J. Edwards, A. J. Gates, A. Hall, G. F. White, J. Bradley, C. Reardon, L. Shi, A. S. Beliaev, M. J. Marshall, Z. Wang, N. J. Watmough, J. Fredrickson, J. Zachara, J. N. Butt, and D. J. Richardson. 2011. “Structure of a Bacterial Cell Surface Decaheme Electron Conduit,” Proceedings of the National Academy of Sciences of the United States, DOI 10.1073/pnas.1017200108.