Long‐range electron transport in random trapping models

1988 ◽  
Vol 88 (4) ◽  
pp. 2692-2699 ◽  
Author(s):  
Kalyan Kundu ◽  
Dora Izzo ◽  
Philip Phillips
Keyword(s):  
Electron Transport ◽  
Long Range

scholarly journals Efficient long-range conduction in cable bacteria through nickel protein wires

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Henricus T. S. Boschker ◽  
Perran L. M. Cook ◽  
Lubos Polerecky ◽  
Raghavendran Thiruvallur Eachambadi ◽  
Helena Lozano ◽  
...  
Keyword(s):  
Electron Transport ◽  
Long Range ◽  
Cell Envelope ◽  
Protein Structures ◽  
Chemical Imaging ◽  
Electrical Currents ◽  
Core Proteins ◽  
Active Metal ◽  
Unknown Form ◽  
High Resolution Microscopy

AbstractFilamentous cable bacteria display long-range electron transport, generating electrical currents over centimeter distances through a highly ordered network of fibers embedded in their cell envelope. The conductivity of these periplasmic wires is exceptionally high for a biological material, but their chemical structure and underlying electron transport mechanism remain unresolved. Here, we combine high-resolution microscopy, spectroscopy, and chemical imaging on individual cable bacterium filaments to demonstrate that the periplasmic wires consist of a conductive protein core surrounded by an insulating protein shell layer. The core proteins contain a sulfur-ligated nickel cofactor, and conductivity decreases when nickel is oxidized or selectively removed. The involvement of nickel as the active metal in biological conduction is remarkable, and suggests a hitherto unknown form of electron transport that enables efficient conduction in centimeter-long protein structures.

scholarly journals Protein Nanowires: the Electrification of the Microbial World and Maybe Our Own

2020 ◽  
Vol 202 (20) ◽  
Author(s):  
Derek R. Lovley ◽  
Dawn E. Holmes
Keyword(s):  
Electron Transport ◽  
Long Range ◽  
Electronic Devices ◽  
Electricity Production ◽  
Microbial World ◽  
Electrically Conductive ◽  
Anaerobic Digesters ◽  
Content Type ◽  
Type Iv ◽  
Type Iv Pilin

ABSTRACT Electrically conductive protein nanowires appear to be widespread in the microbial world and are a revolutionary “green” material for the fabrication of electronic devices. Electrically conductive pili (e-pili) assembled from type IV pilin monomers have independently evolved multiple times in microbial history as have electrically conductive archaella (e-archaella) assembled from homologous archaellin monomers. A role for e-pili in long-range (micrometer) extracellular electron transport has been demonstrated in some microbes. The surprising finding of e-pili in syntrophic bacteria and the role of e-pili as conduits for direct interspecies electron transfer have necessitated a reassessment of routes for electron flux in important methanogenic environments, such as anaerobic digesters and terrestrial wetlands. Pilin monomers similar to those found in e-pili may also be a major building block of the conductive “cables” that transport electrons over centimeter distances through continuous filaments of cable bacteria consisting of a thousand cells or more. Protein nanowires harvested from microbes have many functional and sustainability advantages over traditional nanowire materials and have already yielded novel electronic devices for sustainable electricity production, neuromorphic memory, and sensing. e-pili can be mass produced with an Escherichia coli chassis, providing a ready source of material for electronics as well as for studies on the basic mechanisms for long-range electron transport along protein nanowires. Continued exploration is required to better understand the electrification of microbial communities with microbial nanowires and to expand the “green toolbox” of sustainable materials for wiring and powering the emerging “Internet of things.”

Long-range correlated electron transport in M-DNA

2016 ◽  
Vol 478 ◽  
pp. 45-47
Author(s):  
Aleš Omerzu ◽  
Miloš Borovšak
Keyword(s):  
Electron Transport ◽  
Long Range ◽  
Correlated Electron

scholarly journals Plastocyanin is the long-range electron carrier between photosystem II and photosystem I in plants

2020 ◽  
Vol 117 (26) ◽  
pp. 15354-15362 ◽  
Author(s):  
Ricarda Höhner ◽  
Mathias Pribil ◽  
Miroslava Herbstová ◽  
Laura Susanna Lopez ◽  
Hans-Henning Kunz ◽  
...  
Keyword(s):  
Electron Transport ◽  
Photosystem Ii ◽  
Long Range ◽  
Narrow Range ◽  
Higher Plants ◽  
Regulatory Element ◽  
Photosynthetic Electron Transport ◽  
Electron Carrier ◽  
Mobile Electron ◽  
Electron Carriers

In photosynthetic electron transport, large multiprotein complexes are connected by small diffusible electron carriers, the mobility of which is challenged by macromolecular crowding. For thylakoid membranes of higher plants, a long-standing question has been which of the two mobile electron carriers, plastoquinone or plastocyanin, mediates electron transport from stacked grana thylakoids where photosystem II (PSII) is localized to distant unstacked regions of the thylakoids that harbor PSI. Here, we confirm that plastocyanin is the long-range electron carrier by employing mutants with different grana diameters. Furthermore, our results explain why higher plants have a narrow range of grana diameters since a larger diffusion distance for plastocyanin would jeopardize the efficiency of electron transport. In the light of recent findings that the lumen of thylakoids, which forms the diffusion space of plastocyanin, undergoes dynamic swelling/shrinkage, this study demonstrates that plastocyanin diffusion is a crucial regulatory element of plant photosynthetic electron transport.

scholarly journals Long-range donor-acceptor electron transport mediated by α helices

2019 ◽  
Vol 100 (6) ◽  
Author(s):  
L. S. Brizhik ◽  
J. Luo ◽  
B. M. A. G. Piette ◽  
W. J. Zakrzewski
Keyword(s):  
Electron Transport ◽  
Long Range ◽  
Donor Acceptor

Electron transport properties of -phase Co Ti alloy films with various degrees of long range order

2000 ◽  
Vol 15 (3) ◽  
pp. 451-459
Author(s):  
Y.P. Lee ◽  
K.W. Kim ◽  
J.Y. Rhee ◽  
Y.V. Kudryavtsev ◽  
V.V. Nemoshkalenko ◽  
...  
Keyword(s):  
Electron Transport ◽  
Transport Properties ◽  
Long Range ◽  
Range Order ◽  
Ti Alloy ◽  
Long Range Order ◽  
Alloy Films ◽  
Electron Transport Properties

scholarly journals Aromatic Amino Acids Required for Pili Conductivity and Long-Range Extracellular Electron Transport in Geobacter sulfurreducens

mBio ◽  
2013 ◽  
Vol 4 (2) ◽  
Author(s):  
Madeline Vargas ◽  
Nikhil S. Malvankar ◽  
Pier-Luc Tremblay ◽  
Ching Leang ◽  
Jessica A. Smith ◽  
...  
Keyword(s):  
Amino Acids ◽  
Electron Transport ◽  
Long Range ◽  
Microbial Fuel Cells ◽  
Aromatic Amino Acids ◽  
Geobacter Sulfurreducens ◽  
Control Strain ◽  
Content Type ◽  
Current Production ◽  
Extracellular Electron Transport

ABSTRACTIt has been proposed thatGeobacter sulfurreducensrequires conductive pili for long-range electron transport to Fe(III) oxides and for high-density current production in microbial fuel cells. In order to investigate this further, we constructed a strain ofG. sulfurreducens, designated Aro-5, which produced pili with diminished conductivity. This was accomplished by modifying the amino acid sequence of PilA, the structural pilin protein. An alanine was substituted for each of the five aromatic amino acids in the carboxyl terminus of PilA, the region in whichG. sulfurreducensPilA differs most significantly from the PilAs of microorganisms incapable of long-range extracellular electron transport. Strain Aro-5 produced pili that were properly decorated with the multihemec-type cytochrome OmcS, which is essential for Fe(III) oxide reduction. However, pili preparations of the Aro-5 strain had greatly diminished conductivity and Aro-5 cultures were severely limited in their capacity to reduce Fe(III) compared to the control strain. Current production of the Aro-5 strain, with a graphite anode serving as the electron acceptor, was less than 10% of that of the control strain. The conductivity of the Aro-5 biofilms was 10-fold lower than the control strain’s. These results demonstrate that the pili ofG. sulfurreducensmust be conductive in order for the cells to be effective in extracellular long-range electron transport.IMPORTANCEExtracellular electron transfer byGeobacterspecies plays an important role in the biogeochemistry of soils and sediments and has a number of bioenergy applications. For example, microbial reduction of Fe(III) oxide is one of the most geochemically significant processes in anaerobic soils, aquatic sediments, and aquifers, andGeobacterorganisms are often abundant in such environments.Geobacter sulfurreducensproduces the highest current densities of any known pure culture, and close relatives are often the most abundant organisms colonizing anodes in microbial fuel cells that harvest electricity from wastewater or aquatic sediments. The finding that a strain ofG. sulfurreducensthat produces pili with low conductivity is limited in these extracellular electron transport functions provides further insight into these environmentally significant processes.

Long-range electron transport to Fe(III) oxide via pili with metallic-like conductivity

2012 ◽  
Vol 40 (6) ◽  
pp. 1186-1190 ◽  
Author(s):  
Derek R. Lovley
Keyword(s):  
Electron Transport ◽  
Long Range ◽  
Geobacter Sulfurreducens ◽  
Oxide Reduction ◽  
Electron Hopping ◽  
Electrically Conductive ◽  
Electron Conduction ◽  
Geobacter Species ◽  
Redox Active

The mechanisms for Fe(III) oxide reduction by Geobacter species are of interest because Geobacter species have been shown to play an important role in Fe(III) oxide reduction in a diversity of environments in which Fe(III) reduction is a geochemically significant process. Geobacter species specifically express pili during growth on Fe(III) oxide compared with growth on soluble chelated Fe(III), and mutants that cannot produce pili are unable to effectively reduce Fe(III) oxide. The pili of Geobacter sulfurreducens are electrically conductive along their length under physiologically relevant conditions and exhibit a metallic-like conductivity similar to that observed previously in synthetic organic metals. Metallic-like conductivity in a biological protein filament is a previously unrecognized mechanism for electron transport that differs significantly from the more well-known biological strategy of electron hopping/tunnelling between closely spaced redox-active proteins. The multihaem c-type cytochrome OmcS is specifically associated with pili and is necessary for Fe(III) oxide reduction. However, multiple lines of evidence, including the metallic-like conductivity of the pili and the fact that OmcS molecules are spaced too far apart for electron hopping/tunnelling, indicate that OmcS is not responsible for long-range electron conduction along the pili. The role of OmcS may be to facilitate electron transfer from the pili to Fe(III) oxide. Long-range electron transport via pili with metallic-like conductivity is a paradigm shift that has important implications not only for Fe(III) oxide reduction, but also for interspecies electron exchange in syntrophic microbial communities as well as microbe–electrode interactions and the emerging field of bioelectronics.

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