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Title: Structural Basis for Metallic-Like Conductivity in Microbial Nanowires

Journal Article · · mBio (Online)
 [1];  [2];  [3];  [3];  [4];  [5];  [3];  [6];  [3]
  1. Univ. of Massachusetts, Amherst, MA (United States). Dept. of Physics; Univ. of Massachusetts, Amherst, MA (United States). Dept. of Microbiology
  2. Univ. of Massachusetts, Amherst, MA (United States). Dept. of Microbiology; College of the Holy Cross Worcester, MA (United States). Dept. of Biology
  3. Univ. of Massachusetts, Amherst, MA (United States). Dept. of Microbiology
  4. Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Sciences Directorate
  5. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
  6. Univ. of Massachusetts, Amherst, MA (United States). Dept. of Physics

Direct measurement of multiple physical properties of Geobacter sulfurreducens pili have demonstrated that they possess metallic-like conductivity, but several studies have suggested that metallic-like conductivity is unlikely based on the structures of the G. sulfurreducens pilus predicted from homology models. In order to further evaluate this discrepancy, pili were examined with synchrotron X-ray microdiffraction and rocking-curve X-ray diffraction. Both techniques revealed a periodic 3.2-Å spacing in conductive, wild-type G. sulfurreducens pili that was missing in the nonconductive pili of strain Aro5, which lack key aromatic acids required for conductivity. The intensity of the 3.2-Å peak increased 100-fold when the pH was shifted from 10.5 to 2, corresponding with a previously reported 100-fold increase in pilus conductivity with this pH change. These results suggest a clear structure-function correlation for metallic-like conductivity that can be attributed to overlapping π-orbitals of aromatic amino acids. A homology model of the G. sulfurreducens pilus was constructed with a Pseudomonas aeruginosa pilus model as a template as an alternative to previous models, which were based on a Neisseria gonorrhoeae pilus structure. This alternative model predicted that aromatic amino acids in G. sulfurreducens pili are packed within 3 to 4 Å, consistent with the experimental results. Thus, the predictions of homology modeling are highly sensitive to assumptions inherent in the model construction. Finally, the experimental results reported here further support the concept that the pili of G. sulfurreducens represent a novel class of electronically functional proteins in which aromatic amino acids promote long-distance electron transport.

Research Organization:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
Grant/Contract Number:
AC02-98CH10886; N00014-13-1-0550; N00014-12-1-0229
OSTI ID:
1259267
Journal Information:
mBio (Online), Vol. 6, Issue 2; ISSN 2150-7511
Publisher:
American Society for MicrobiologyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 137 works
Citation information provided by
Web of Science

References (48)

Microbial Nanowires: A New Paradigm for Biological Electron Transfer and Bioelectronics journal May 2012
Microbial nanowires for bioenergy applications journal June 2014
Electrobiocommodities: powering microbial production of fuels and commodity chemicals from carbon dioxide with electricity journal June 2013
Electron Transfer and Electronic Conduction through an Intervening Medium journal August 2008
Tunable metallic-like conductivity in microbial nanowire networks journal August 2011
Extracellular electron transfer via microbial nanowires journal June 2005
Direct Interspecies Electron Transfer between Geobacter metallireducens and Methanosarcina barkeri journal May 2014
Biofilm conductivity is a decisive variable for high-current-density Geobacter sulfurreducens microbial fuel cells journal January 2012
Biofilm and Nanowire Production Leads to Increased Current in Geobacter sulfurreducens Fuel Cells journal August 2006
Anode Biofilm Transcriptomics Reveals Outer Surface Components Essential for High Density Current Production in Geobacter sulfurreducens Fuel Cells journal May 2009
Seeing is believing: novel imaging techniques help clarify microbial nanowire structure and function: Resolving microbial nanowire structure and function journal January 2015
A natural source of nanowires journal September 2011
Metallic transport in polyaniline journal May 2006
A Geobacter sulfurreducens Strain Expressing Pseudomonas aeruginosa Type IV Pili Localizes OmcS on Pili but Is Deficient in Fe(III) Oxide Reduction and Current Production journal December 2013
Stepping stones in the electron transport from cells to electrodes in Geobacter sulfurreducens biofilms journal January 2013
Molecular Dissection of Bacterial Nanowires journal May 2013
Structure of the Type IVa Major Pilin from the Electrically Conductive Bacterial Nanowires of Geobacter sulfurreducens journal August 2013
Molecular and Electronic Structure of the Peptide Subunit of Geobacter sulfurreducens Conductive Pili from First Principles
  • Feliciano, Gustavo T.; da Silva, Antonio J. R.; Reguera, Gemma
  • The Journal of Physical Chemistry A, Vol. 116, Issue 30, p. 8023-8030 https://doi.org/10.1021/jp302232p
journal July 2012
Type IV Pilus Structure by Cryo-Electron Microscopy and Crystallography: Implications for Pilus Assembly and Functions journal September 2006
Type IV pilus structure and bacterial pathogenicity journal May 2004
An investigation of the conductivity of peptide nanotube networks prepared by enzyme-triggered self-assembly journal January 2010
Rethinking the term “pi-stacking” journal January 2012
A critical account on π–π stacking in metal complexes with aromatic nitrogen-containing ligands † journal January 2000
High-resolution X-ray diffraction analyses of protein crystals
  • Volz, H. M.; Matyi, R. J.
  • Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, Vol. 357, Issue 1761 https://doi.org/10.1098/rsta.1999.0466
journal October 1999
Accurate rocking-curve measurements on protein crystals grown in a homogeneous magnetic field of 2.4 T journal May 2004
Charge-Transfer and Energy-Transfer Processes in π-Conjugated Oligomers and Polymers:  A Molecular Picture journal November 2004
Organic semiconductors: A theoretical characterization of the basic parameters governing charge transport journal April 2002
One-Dimensional Optoelectronic Nanostructures Derived from the Aqueous Self-Assembly of π-Conjugated Oligopeptides journal October 2008
On-resin dimerization incorporates a diverse array of π-conjugated functionality within aqueous self-assembling peptide backbones journal January 2010
Lack of cytochrome involvement in long-range electron transport through conductive biofilms and nanowires of Geobacter sulfurreducens journal January 2012
Type IV Pilin Structure and Assembly journal May 2003
Design of Self-Assembling Peptide Nanotubes with Delocalized Electronic States journal January 2006
Stroboscopic imaging of macromolecular complexes journal May 2013
Selection of a variant of Geobacter sulfurreducens with enhanced capacity for current production in microbial fuel cells journal August 2009
Power output and columbic efficiencies from biofilms of Geobacter sulfurreducens comparable to mixed community microbial fuel cells: High current production with a pure culture journal June 2008
PilX, a pilus-associated protein essential for bacterial aggregation, is a key to pilus-facilitated attachment of Neisseria meningitidis to human cells: Aggregation and pilus-facilitated adherence journal October 2004
Hrp pilus: An hrp-dependent bacterial surface appendage produced by Pseudomonas syringae pv. tomato DC3000 journal April 1997
‘Polyaniline’: Protonic acid doping of the emeraldine form to the metallic regime journal January 1986
Bulk and interface investigations of scaffolds and tissue-engineered bones by X-ray microtomography and X-ray microdiffraction journal May 2007
An In Situ Synchrotron Study of Zinc Anode Planarization by a Bismuth Additive journal December 2013
MolProbity : all-atom structure validation for macromolecular crystallography journal December 2009
Toward the estimation of the absolute quality of individual protein structure models journal December 2010
ConSurf 2010: calculating evolutionary conservation in sequence and structure of proteins and nucleic acids journal May 2010
Jmol – a paradigm shift in crystallographic visualization journal September 2010
van der Waals Volumes and Radii journal March 1964
Exploring the gas access routes in a [NiFeSe] hydrogenase using crystals pressurized with krypton and oxygen journal August 2020
Charge-Transfer and Energy-Transfer Processes in ?-Conjugated Oligomers and Polymers: A Molecular Picture journal February 2005
Structure of the Type IVa Major Pilin from the Electrically Conductive Bacterial Nanowires of Geobacter sulfurreducens dataset January 2013

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Enhanced Growth of Pilin-Deficient Geobacter sulfurreducens Mutants in Carbon Poor and Electron Donor Limiting Conditions journal February 2019
Biological synthesis of high-conductive pili in aerobic bacterium Pseudomonas aeruginosa journal December 2018
Terahertz-infrared spectroscopy of Shewanella oneidensis MR-1 extracellular matrix journal May 2018
A review of the mechanisms of mineral-based metabolism in early Earth analog rock-hosted hydrothermal ecosystems journal January 2019
Enhancing bioelectricity generation in microbial fuel cells and biophotovoltaics using nanomaterials journal June 2019
Happy together: microbial communities that hook up to swap electrons journal November 2016
Electrically conductive pili from pilin genes of phylogenetically diverse microorganisms journal September 2017
Intercellular wiring enables electron transfer between methanotrophic archaea and bacteria journal October 2015
Structure of the Neisseria meningitidis Type IV pilus journal October 2016
Formation of bacterial pilus-like nanofibres by designed minimalistic self-assembling peptides journal November 2016
Microbial substrate preference dictated by energy demand rather than supply journal July 2017
Extracellular electron transfer mechanisms between microorganisms and minerals journal August 2016
Syntrophus conductive pili demonstrate that common hydrogen-donating syntrophs can have a direct electron transfer option journal January 2020
The progress and outlook of bioelectrocatalysis for the production of chemicals, fuels and materials journal January 2020
Cryo-EM reveals the structural basis of long-range electron transport in a cytochrome-based bacterial nanowire journal June 2019
Low Energy Atomic Models Suggesting a Pilus Structure that could Account for Electrical Conductivity of Geobacter sulfurreducens Pili journal March 2016
Structural and functional insights into the conductive pili of Geobacter sulfurreducens revealed in molecular dynamics simulations journal January 2015
Ultrastructure of Shewanella oneidensis MR-1 nanowires revealed by electron cryotomography journal March 2018
Biomimetic engineering of conductive curli protein films journal September 2018
Protein bioelectronics: a review of what we do and do not know journal January 2018
Microbial nanowires and electroactive biofilms journal May 2018
The electrically conductive pili of Geobacter species are a recently evolved feature for extracellular electron transfer journal August 2016
Microbial nanowires: an electrifying tale journal December 2016
Candidatus Desulfofervidus auxilii, a hydrogenotrophic sulfate-reducing bacterium involved in the thermophilic anaerobic oxidation of methane : The partner bacterium in thermophilic methanotrophy journal April 2016
Harnessing the power of microbial nanowires journal May 2018
Phylogenetic and structural diversity of aromatically dense pili from environmental metagenomes journal October 2019
Molecular evidence for the adaptive evolution of Geobacter sulfurreducens to perform dissimilatory iron reduction in natural environments journal December 2019
e-Biologics: Fabrication of Sustainable Electronics with “Green” Biological Materials journal June 2017
Geobacter Strains Expressing Poorly Conductive Pili Reveal Constraints on Direct Interspecies Electron Transfer Mechanisms journal July 2018
Direct Extracellular Electron Transfer of the Geobacter sulfurreducens Pili Relevant to Interaromatic Distances journal November 2019
Microbial electron transport and energy conservation – the foundation for optimizing bioelectrochemical systems journal June 2015
The Low Conductivity of Geobacter uraniireducens Pili Suggests a Diversity of Extracellular Electron Transfer Mechanisms in the Genus Geobacter journal June 2016
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Comparative Analysis of Type IV Pilin in Desulfuromonadales journal December 2016
Anodic and Cathodic Extracellular Electron Transfer by the Filamentous Bacterium Ardenticatena maritima 110S journal February 2018
Stimulatory Effect of Magnetite Nanoparticles on a Highly Enriched Butyrate-Oxidizing Consortium journal July 2018
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