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Nanowires project from bacteria to facilitate transfer of electrons
Credit: Yale University
These nanowires enable the bacteria to perform environmentally important functions such as cleaning up radioactive sites and generating electricity. Scientists have long known that Geobacter make conductive nanowires – 1/100,000 the width of a human hair – but to date no one had discovered what they are made of and why they are conductive.
A new study by researchers at Yale, University of Virginia and the University of California at Irvine published April 4 in the journal Cell reveals a surprise: the protein nanowires have a core of metal-containing molecules called hemes.
Previously nobody suspected such a structure. Using high-resolution cryo-electron microscopy, the researchers were able to see the nanowire's atomic structure and discover that hemes line up to create a continuous path along which electrons travel.
“This study solves a longstanding mystery of how nanowires move electrons to minerals in the soil,” said lead author Nikhil Malvankar, assistant professor of molecular biophysics and biochemistry at Yale and a faculty member at the Microbial Sciences Institute.
“It is possible we could use these wires to connect cells to electronics to build new types of materials and sensors.”
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Edward Egelman of Virginia and Allon Hochbaum of UC-Irvine are other senior authors. Fengbin Wang of Virginia and Yale's Yangqi Gu and are co-first authors. Other authors are Yale's Patrick O'Brien, Sophia Yi, Sibel Ebru Yalcin, Vishok Srikanth, Cong Shen, Dennis Vu and UC Irvine's Nicole Ing.