Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Structure of bacterial nanowire protein hints at secrets of conduction: Electrically conducting bacteria important for energy, environment and technology

Zooming in on the Geobacter-Gonorrhea composite shows how the aromatic residues (teal balloon-like structures) bulge from the surface of pilin proteins (variously colored helical structures) within the fiber.
Zooming in on the Geobacter-Gonorrhea composite shows how the aromatic residues (teal balloon-like structures) bulge from the surface of pilin proteins (variously colored helical structures) within the fiber.

Abstract:
Tiny electrical wires protrude from some bacteria and contribute to rock and dirt formation. Researchers studying the protein that makes up one such wire have determined the protein's structure. The finding is important to such diverse fields as producing energy, recycling Earth's carbon and miniaturizing computers.

Structure of bacterial nanowire protein hints at secrets of conduction: Electrically conducting bacteria important for energy, environment and technology

Richland, WA | Posted on November 12th, 2013

"This is the first atomic resolution structure of this protein from an electrically conductive bacterial species, and it sets the foundation for understanding how these nanowires work," said structural biologist Patrick Reardon of the Department of Energy's Pacific Northwest National Laboratory. Reardon is the 2012 William R. Wiley Distinguished Postdoctoral Fellow at EMSL, the DOE's Environmental Molecular Sciences Laboratory at PNNL.

With the help of related structures on disease-causing bacteria, the researchers show that the protein's shape and form suggest possible ways for the bacteria to shuttle electrons along the nanowire. The results were reported in October in the Journal of Biological Chemistry.

"How to get electrons from the inside of bacteria to the outside is important for many different things, such as bacterial fuel cells, how carbon cycles through the environment and how to make new nanomaterials for applications like biocomputers," said Reardon.

Aromatic Therapy

Many bacterial species wave fingerlike projections along their bodies. The bacteria use these fingers, called pili, to adhere to surfaces or weave into films or recognize objects in the environment. A group of related bacteria makes these bendy, stretchy structures out of a protein called pilin, and an even smaller group uses these structures like electrical wires.

Researchers and engineers would like to take advantage of this wiring. Bacteria produce electrons while respiring and use the wires to run electrons out of their little bacterial bodies. Normally the electrons build up or break down minerals in rock, but the system can also be used to clean up toxic heavy metals or to run a bacterial fuel cell.

To better understand how pilins contribute to conduction, Reardon and NMR lead scientist Karl Mueller explored pilin from an electrically conducting bacteria known as Geobacter sulfurreducens.

Previous research on Geobacter's pilin — PilA — provided a big hint. PilA required certain spots along its length known as aromatic residues to conduct electricity. Without those aromatic residues where they were, Geobacter had no zip in its pili.

But proteins are like a long string that folds up into a compact three-dimensional shape. Without knowing the shape of pilin, it wasn't clear where the aromatic residues landed in space or how they contributed to electron shuttling.

Hop or Flow?

To find out, the researchers used NMR — a technology similar to medical MRIs — at EMSL to picture the shape of PilA.

On its own, PilA looks like a long skinny spring, with a slight kink about halfway up. The aromatic residues, which are bulky anyway, bulge along its length. But the protein by itself isn't enough to reveal how conduction works. Many pilin proteins work together to form a fiber, and Reardon and Mueller only had one.

Nor did the researchers have the whole fiber to put into the NMR instrument. To get more clues, Reardon borrowed the computer image of an assembled fiber from an unrelated species, the bacteria that cause gonorrhea. Gonorrhea's fiber does not conduct electricity nor does its pilin have as many aromatic residues. But its pilin has a similar shape to PilA, so using a computer program, Reardon overlaid PilA on its Gonorrhea cousins.

At this point, the aromatic residues clearly stood out.

"We get clusters of aromatic residues, and they wrap along the wire candy cane style," said Reardon.

But that just raised another question. If the electrons traveling along Geobacter's pilin are using these aromatic residues, they could be hopping from aromatic island to aromatic island. Alternatively, the aromatic residues could be close enough to pass the electrons through like a baton in a running race. Reardon and Mueller agree the single structure is not enough to choose between the two options.

The next step, Mueller said, is to purify the whole fiber from Geobacter microbes and determine the complete structure. The task is technologically challenging however because the fiber has to be grown within the bacteria themselves. Visualizing the whole fiber, though, will show the scientists if the fiber resembles islands in a stream more, or the streambed itself.

This work was supported by the Department of Energy's Office of Science.

####

About DOE/Pacific Northwest National Laboratory
Interdisciplinary teams at Pacific Northwest National Laboratory address many of America's most pressing issues in energy, the environment and national security through advances in basic and applied science. Founded in 1965, PNNL employs 4,300 staff and has an annual budget of about $950 million. It is managed by Battelle for the U.S. Department of Energy. For more information, visit the PNNL News Center, or follow PNNL on Facebook, Google+, LinkedIn and Twitter.

EMSL, the Environmental Molecular Sciences Laboratory, is a national scientific user facility sponsored by the Department of Energy's Office of Science. Located at Pacific Northwest National Laboratory in Richland, Wash., EMSL offers an open, collaborative environment for scientific discovery to researchers around the world. Its integrated computational and experimental resources enable researchers to realize important scientific insights and create new technologies. Follow EMSL on Facebook, LinkedIn and Twitter.

The Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.

For more information, please click here

Contacts:
Mary Beckman

509-375-3688

Copyright © DOE/Pacific Northwest National Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Reference: Patrick N. Reardon, and Karl T. Mueller. Structure of the Type IVa Major Pilin from the Electrically Conductive Bacterial Nanowires of Geobacter sulfurreducens, J. Biol. Chem. Oct. 11, 2013, DOI: 10.1074/jbc.M113.498527:

Related News Press

News and information

Halas wins American Physical Society's Lilienfeld Prize: Rice University nanoscientist honored for pioneering research in plasmonics October 23rd, 2017

GTC Shanghai Highlights GF’s Momentum in China: Company shares details of technology roadmap and customer adoption in the world’s fastest-growing market for semiconductors October 23rd, 2017

Nanobiotix completes patient inclusion for Phase II/III trial of NBTXR3 in soft tissue sarcoma October 23rd, 2017

Arrowhead Pharmaceuticals Reports Inducement Grants under NASDAQ Marketplace Rule 5635(c)(4) October 23rd, 2017

Laboratories

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Videos/Movies

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Bringing the atomic world into full color: Researchers turn atomic force microscope measurements into color images October 19th, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Nanobiotix completes patient inclusion for Phase II/III trial of NBTXR3 in soft tissue sarcoma October 23rd, 2017

Researchers bring optical communication onto silicon chips: Ultrathin films of a semiconductor that emits and detects light can be stacked on top of silicon wafers October 23rd, 2017

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Tech’s Contribution Includes Liten’s Knowhow in Magnetic Materials and Simulation And Leti’s Expertise in Wide-bandgap Semiconductors October 20th, 2017

Chip Technology

GTC Shanghai Highlights GF’s Momentum in China: Company shares details of technology roadmap and customer adoption in the world’s fastest-growing market for semiconductors October 23rd, 2017

Researchers bring optical communication onto silicon chips: Ultrathin films of a semiconductor that emits and detects light can be stacked on top of silicon wafers October 23rd, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

MIPT scientists revisit optical constants of ultrathin gold films October 20th, 2017

Discoveries

Researchers bring optical communication onto silicon chips: Ultrathin films of a semiconductor that emits and detects light can be stacked on top of silicon wafers October 23rd, 2017

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

A step closer to understanding quantum mechanics: Swansea University’s physicists develop a new quantum simulation protocol October 22nd, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Announcements

Nanobiotix completes patient inclusion for Phase II/III trial of NBTXR3 in soft tissue sarcoma October 23rd, 2017

Arrowhead Pharmaceuticals Reports Inducement Grants under NASDAQ Marketplace Rule 5635(c)(4) October 23rd, 2017

Researchers bring optical communication onto silicon chips: Ultrathin films of a semiconductor that emits and detects light can be stacked on top of silicon wafers October 23rd, 2017

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

A step closer to understanding quantum mechanics: Swansea University’s physicists develop a new quantum simulation protocol October 22nd, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

Environment

Single ‘solitons’ promising for optical technologies October 9th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

High-tech electronics made from autumn leaves: New process converts biomass waste into useful electronic devices August 30th, 2017

Nanoparticles pollution rises 30 percent when flex-fuel cars switch from bio to fossil: Study carried out in São Paulo, home to the world's largest flex fuel urban fleet, shows increase of ultrafine particulate matter when ethanol prices rose and consumption fell August 28th, 2017

Energy

New nanomaterial can extract hydrogen fuel from seawater: Hybrid material converts more sunlight and can weather seawater's harsh conditions October 4th, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

Nanobiotechnology

Nanobiotix completes patient inclusion for Phase II/III trial of NBTXR3 in soft tissue sarcoma October 23rd, 2017

Arrowhead Pharmaceuticals Reports Inducement Grants under NASDAQ Marketplace Rule 5635(c)(4) October 23rd, 2017

Arrowhead Presents Promising Preclinical Data on Development of ARO-AAT for Treatment of Alpha-1 Liver Disease at Liver Meeting(R) 2017 October 23rd, 2017

Spinning strands hint at folding dynamics: Rice University lab uses magnetic beads to model microscopic proteins, polymers October 17th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project