Deep in the ocean or underground, where there is no oxygen, Geobacter bacteria "breathe" by projecting tiny protein filaments called "nanowires" into the soil, to dispose of excess electrons resulting from the conversion of nutrients to energy.
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."
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.
Bill Hathaway | EurekAlert!
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The operational speed of semiconductors in various electronic and optoelectronic devices is limited to several gigahertz (a billion oscillations per second). This constrains the upper limit of the operational speed of computing. Now researchers from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg, Germany, and the Indian Institute of Technology in Bombay have explained how these processes can be sped up through the use of light waves and defected solid materials.
Light waves perform several hundred trillion oscillations per second. Hence, it is natural to envision employing light oscillations to drive the electronic...
Most natural and artificial surfaces are rough: metals and even glasses that appear smooth to the naked eye can look like jagged mountain ranges under the microscope. There is currently no uniform theory about the origin of this roughness despite it being observed on all scales, from the atomic to the tectonic. Scientists suspect that the rough surface is formed by irreversible plastic deformation that occurs in many processes of mechanical machining of components such as milling.
Prof. Dr. Lars Pastewka from the Simulation group at the Department of Microsystems Engineering at the University of Freiburg and his team have simulated such...
Investigation of the temperature dependence of the skyrmion Hall effect reveals further insights into possible new data storage devices
The joint research project of Johannes Gutenberg University Mainz (JGU) and the Massachusetts Institute of Technology (MIT) that had previously demonstrated...
Researchers at Chalmers University of Technology, Sweden, recently completed a 5-year research project looking at how to make fibre optic communications systems more energy efficient. Among their proposals are smart, error-correcting data chip circuits, which they refined to be 10 times less energy consumptive. The project has yielded several scientific articles, in publications including Nature Communications.
Streaming films and music, scrolling through social media, and using cloud-based storage services are everyday activities now.
After helping develop a new approach for organic synthesis -- carbon-hydrogen functionalization -- scientists at Emory University are now showing how this approach may apply to drug discovery. Nature Catalysis published their most recent work -- a streamlined process for making a three-dimensional scaffold of keen interest to the pharmaceutical industry.
"Our tools open up whole new chemical space for potential drug targets," says Huw Davies, Emory professor of organic chemistry and senior author of the paper.
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