1
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Liang J, Xiao K, Wang X, Hou T, Zeng C, Gao X, Wang B, Zhong C. Revisiting Solar Energy Flow in Nanomaterial-Microorganism Hybrid Systems. Chem Rev 2024. [PMID: 38900019 DOI: 10.1021/acs.chemrev.3c00831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Nanomaterial-microorganism hybrid systems (NMHSs), integrating semiconductor nanomaterials with microorganisms, present a promising platform for broadband solar energy harvesting, high-efficiency carbon reduction, and sustainable chemical production. While studies underscore its potential in diverse solar-to-chemical energy conversions, prevailing NMHSs grapple with suboptimal energy conversion efficiency. Such limitations stem predominantly from an insufficient systematic exploration of the mechanisms dictating solar energy flow. This review provides a systematic overview of the notable advancements in this nascent field, with a particular focus on the discussion of three pivotal steps of energy flow: solar energy capture, cross-membrane energy transport, and energy conversion into chemicals. While key challenges faced in each stage are independently identified and discussed, viable solutions are correspondingly postulated. In view of the interplay of the three steps in affecting the overall efficiency of solar-to-chemical energy conversion, subsequent discussions thus take an integrative and systematic viewpoint to comprehend, analyze and improve the solar energy flow in the current NMHSs of different configurations, and highlighting the contemporary techniques that can be employed to investigate various aspects of energy flow within NMHSs. Finally, a concluding section summarizes opportunities for future research, providing a roadmap for the continued development and optimization of NMHSs.
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Affiliation(s)
- Jun Liang
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Kemeng Xiao
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xinyu Wang
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Tianfeng Hou
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Cuiping Zeng
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Xiang Gao
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Bo Wang
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Chao Zhong
- Key Laboratory of Quantitative Synthetic Biology, Center for Materials Synthetic Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
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2
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Pankratov D, Hidalgo Martinez S, Karman C, Gerzhik A, Gomila G, Trashin S, Boschker HTS, Geelhoed JS, Mayer D, De Wael K, J R Meysman F. The organo-metal-like nature of long-range conduction in cable bacteria. Bioelectrochemistry 2024; 157:108675. [PMID: 38422765 DOI: 10.1016/j.bioelechem.2024.108675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 02/22/2024] [Accepted: 02/24/2024] [Indexed: 03/02/2024]
Abstract
Cable bacteria are filamentous, multicellular microorganisms that display an exceptional form of biological electron transport across centimeter-scale distances. Currents are guided through a network of nickel-containing protein fibers within the cell envelope. Still, the mechanism of long-range conduction remains unresolved. Here, we characterize the conductance of the fiber network under dry and wet, physiologically relevant, conditions. Our data reveal that the fiber conductivity is high (median value: 27 S cm-1; range: 2 to 564 S cm-1), does not show any redox signature, has a low thermal activation energy (Ea = 69 ± 23 meV), and is not affected by humidity or the presence of ions. These features set the nickel-based conduction mechanism in cable bacteria apart from other known forms of biological electron transport. As such, conduction resembles that of an organic semi-metal with a high charge carrier density. Our observation that biochemistry can synthesize an organo-metal-like structure opens the way for novel bio-based electronic technologies.
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Affiliation(s)
- Dmitrii Pankratov
- Geobiology Group, Microbial Systems Technology Excellence Centre, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium; A-Sense Lab, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Silvia Hidalgo Martinez
- Geobiology Group, Microbial Systems Technology Excellence Centre, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Cheryl Karman
- Geobiology Group, Microbial Systems Technology Excellence Centre, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium; A-Sense Lab, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Anastasia Gerzhik
- Institute of Biological Information Processing, Bioelectronics (IBI-3), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Gabriel Gomila
- Nanoscale Bioelectric Characterization Group, Institute for Bioengineering of Catalunya (IBEC), The Barcelona Institute of Science and Technology, Baldiri i Reixac 15-21, 08028 Barcelona, Spain; Department of Electronics and Biomedical Engineering, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona, Spain
| | - Stanislav Trashin
- A-Sense Lab, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Henricus T S Boschker
- Geobiology Group, Microbial Systems Technology Excellence Centre, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, the Netherlands
| | - Jeanine S Geelhoed
- Geobiology Group, Microbial Systems Technology Excellence Centre, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium
| | - Dirk Mayer
- Institute of Biological Information Processing, Bioelectronics (IBI-3), Forschungszentrum Jülich, 52428 Jülich, Germany
| | - Karolien De Wael
- A-Sense Lab, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
| | - Filip J R Meysman
- Geobiology Group, Microbial Systems Technology Excellence Centre, Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk, Belgium; Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ Delft, the Netherlands.
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3
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Guberman-Pfeffer MJ. To be or not to be a cytochrome: electrical characterizations are inconsistent with Geobacter cytochrome 'nanowires'. Front Microbiol 2024; 15:1397124. [PMID: 38633696 PMCID: PMC11021709 DOI: 10.3389/fmicb.2024.1397124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 03/21/2024] [Indexed: 04/19/2024] Open
Abstract
Geobacter sulfurreducens profoundly shapes Earth's biogeochemistry by discharging respiratory electrons to minerals and other microbes through filaments of a two-decades-long debated identity. Cryogenic electron microscopy has revealed filaments of redox-active cytochromes, but the same filaments have exhibited hallmarks of organic metal-like conductivity under cytochrome denaturing/inhibiting conditions. Prior structure-based calculations and kinetic analyses on multi-heme proteins are synthesized herein to propose that a minimum of ~7 cytochrome 'nanowires' can carry the respiratory flux of a Geobacter cell, which is known to express somewhat more (≥20) filaments to increase the likelihood of productive contacts. By contrast, prior electrical and spectroscopic structural characterizations are argued to be physiologically irrelevant or physically implausible for the known cytochrome filaments because of experimental artifacts and sample impurities. This perspective clarifies our mechanistic understanding of physiological metal-microbe interactions and advances synthetic biology efforts to optimize those interactions for bioremediation and energy or chemical production.
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4
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van der Veen JR, Valianti S, van der Zant HSJ, Blanter YM, Meysman FJR. A model analysis of centimeter-long electron transport in cable bacteria. Phys Chem Chem Phys 2024; 26:3139-3151. [PMID: 38189548 DOI: 10.1039/d3cp04466a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The recent discovery of cable bacteria has greatly expanded the known length scale of biological electron transport, as these multi-cellular bacteria are capable of mediating electrical currents across centimeter-scale distances. To enable such long-range conduction, cable bacteria embed a network of regularly spaced, parallel protein fibers in their cell envelope. These fibers exhibit extraordinary electrical properties for a biological material, including an electrical conductivity that can exceed 100 S cm-1. Traditionally, long-range electron transport through proteins is described as a multi-step hopping process, in which the individual hopping steps are described by Marcus electron transport theory. Here, we investigate to what extent such a classical hopping model can explain the conductance data recorded for individual cable bacterium filaments. To this end, the conductive fiber network in cable bacteria is modelled as a set of parallel one-dimensional hopping chains. Comparison of model simulated and experimental current(I)/voltage(V) curves, reveals that the charge transport is field-driven rather than concentration-driven, and there is no significant injection barrier between electrodes and filaments. However, the observed high conductivity levels (>100 S cm-1) can only be reproduced, if we include much longer hopping distances (a > 10 nm) and lower reorganisation energies (λ < 0.2 eV) than conventionally used in electron relay models of protein structures. Overall, our model analysis suggests that the conduction mechanism in cable bacteria is markedly distinct from other known forms of long-range biological electron transport, such as in multi-heme cytochromes.
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Affiliation(s)
- Jasper R van der Veen
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft, 2628CJ, The Netherlands.
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft, 2629HZ, The Netherlands
| | - Stephanie Valianti
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft, 2628CJ, The Netherlands.
| | - Herre S J van der Zant
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft, 2628CJ, The Netherlands.
| | - Yaroslav M Blanter
- Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft, 2628CJ, The Netherlands.
| | - Filip J R Meysman
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, Delft, 2629HZ, The Netherlands
- Excellence center for Microbial Systems Technology, University of Antwerp, Universiteitsplein 1, Wilrijk, 2610, Belgium.
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5
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Kulke M, Olson DM, Huang J, Kramer DM, Vermaas JV. Long-Range Electron Transport Rates Depend on Wire Dimensions in Cytochrome Nanowires. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2304013. [PMID: 37653599 DOI: 10.1002/smll.202304013] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/18/2023] [Indexed: 09/02/2023]
Abstract
The ability to redirect electron transport to new reactions in living systems opens possibilities to store energy, generate new products, or probe physiological processes. Recent work by Huang et al. showed that 3D crystals of small tetraheme cytochromes (STC) can transport electrons over nanoscopic to mesoscopic distances by an electron hopping mechanism, making them promising materials for nanowires. However, fluctuations at room temperature may distort the nanostructure, hindering efficient electron transport. Classical molecular dynamics simulations of these fluctuations at the nano- and mesoscopic scales allowed us to develop a graph network representation to estimate maximum electron flow that can be driven through STC wires. In longer nanowires, transient structural fluctuations at protein-protein interfaces tended to obstruct efficient electron transfer, but these blockages are ameliorated in thicker crystals where alternative electron transfer pathways become more efficient. The model implies that more flexible proteinprotein interfaces limit the required minimum diameter to carry currents commensurate with conventional electronics.
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Affiliation(s)
- Martin Kulke
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, 612 Wilson Rd, East Lansing, MI, 48824, United States of America
| | - Dayna M Olson
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, 612 Wilson Rd, East Lansing, MI, 48824, United States of America
| | - Jingcheng Huang
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, 612 Wilson Rd, East Lansing, MI, 48824, United States of America
| | - David M Kramer
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, 612 Wilson Rd, East Lansing, MI, 48824, United States of America
| | - Josh V Vermaas
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, 612 Wilson Rd, East Lansing, MI, 48824, United States of America
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6
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Vacek J, Zatloukalová M, Dorčák V, Cifra M, Futera Z, Ostatná V. Electrochemistry in sensing of molecular interactions of proteins and their behavior in an electric field. Mikrochim Acta 2023; 190:442. [PMID: 37847341 PMCID: PMC10582152 DOI: 10.1007/s00604-023-05999-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/12/2023] [Indexed: 10/18/2023]
Abstract
Electrochemical methods can be used not only for the sensitive analysis of proteins but also for deeper research into their structure, transport functions (transfer of electrons and protons), and sensing their interactions with soft and solid surfaces. Last but not least, electrochemical tools are useful for investigating the effect of an electric field on protein structure, the direct application of electrochemical methods for controlling protein function, or the micromanipulation of supramolecular protein structures. There are many experimental arrangements (modalities), from the classic configuration that works with an electrochemical cell to miniaturized electrochemical sensors and microchip platforms. The support of computational chemistry methods which appropriately complement the interpretation framework of experimental results is also important. This text describes recent directions in electrochemical methods for the determination of proteins and briefly summarizes available methodologies for the selective labeling of proteins using redox-active probes. Attention is also paid to the theoretical aspects of electron transport and the effect of an external electric field on the structure of selected proteins. Instead of providing a comprehensive overview, we aim to highlight areas of interest that have not been summarized recently, but, at the same time, represent current trends in the field.
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Affiliation(s)
- Jan Vacek
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, 77515, Olomouc, Czech Republic.
| | - Martina Zatloukalová
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, 77515, Olomouc, Czech Republic
| | - Vlastimil Dorčák
- Department of Medical Chemistry and Biochemistry, Faculty of Medicine and Dentistry, Palacky University, Hnevotinska 3, 77515, Olomouc, Czech Republic
| | - Michal Cifra
- Institute of Photonics and Electronics of the Czech Academy of Sciences, Chaberska 1014/57, 18200, Prague, Czech Republic
| | - Zdeněk Futera
- Faculty of Science, University of South Bohemia, Branisovska 1760, 37005, Ceske Budejovice, Czech Republic
| | - Veronika Ostatná
- Institute of Biophysics, The Czech Academy of Sciences, v.v.i., Kralovopolska 135, 61200, Brno, Czech Republic
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7
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Kontkanen OV, Biriukov D, Futera Z. Applicability of perturbed matrix method for charge transfer studies at bio/metallic interfaces: a case of azurin. Phys Chem Chem Phys 2023; 25:12479-12489. [PMID: 37097130 DOI: 10.1039/d3cp00197k] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
As the field of nanoelectronics based on biomolecules such as peptides and proteins rapidly grows, there is a need for robust computational methods able to reliably predict charge transfer properties at bio/metallic interfaces. Traditionally, hybrid quantum-mechanical/molecular-mechanical techniques are employed for systems where the electron hopping transfer mechanism is applicable to determine physical parameters controlling the thermodynamics and kinetics of charge transfer processes. However, these approaches are limited by a relatively high computational cost when extensive sampling of a configurational space is required, like in the case of soft biomatter. For these applications, semi-empirical approaches such as the perturbed matrix method (PMM) have been developed and successfully used to study charge-transfer processes in biomolecules. Here, we explore the performance of PMM on prototypical redox-active protein azurin in various environments, from solution to vacuum interfaces with gold surfaces and protein junction. We systematically benchmarked the robustness and convergence of the method with respect to the quantum-centre size, size of the Hamiltonian, number of samples, and level of theory. We show that PMM can adequately capture all the trends associated with the structural and electronic changes related to azurin oxidation at bio/metallic interfaces.
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Affiliation(s)
- Outi Vilhelmiina Kontkanen
- Faculty of Science, University of South Bohemia, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic.
| | - Denys Biriukov
- Faculty of Science, University of South Bohemia, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic.
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, 16610 Prague 6, Czech Republic
| | - Zdenek Futera
- Faculty of Science, University of South Bohemia, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic.
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8
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Feng L, He S, Gao Z, Zhao W, Jiang J, Zhao Q, Wei L. Mechanisms, performance, and the impact on microbial structure of direct interspecies electron transfer for enhancing anaerobic digestion-A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 862:160813. [PMID: 36502975 DOI: 10.1016/j.scitotenv.2022.160813] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 11/22/2022] [Accepted: 12/05/2022] [Indexed: 06/17/2023]
Abstract
Direct interspecies electron transfer (DIET) has been received tremendous attention, recently, due to the advantages of accelerating methane production via organics reduction during anaerobic digestion (AD) process. DIET-based syntrophic relationships not only occurred with the existence of pili and some proteins in the microorganism, but also can be conducted by conductive materials. Therefore, more researches into understanding and strengthening DIET-based syntrophy have been conducted with the aim of improving methanogenesis kinetics and further enhance methane productivity in AD systems. This study summarized the mechanisms, application and microbial structures of typical conductive materials (carbon-based materials and iron-based materials) during AD reactors operation. Meanwhile, detail analysis of studies on DIET (from substrates, dosage and effectiveness) via conductive materials was also presented in the study. Moreover, the challenges of applying conductive materials in boosting methane production were also proposed, which was supposed to provide a deep insight in DIET for full scale application.
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Affiliation(s)
- Likui Feng
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Shufei He
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Zhelu Gao
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Weixin Zhao
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Junqiu Jiang
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Qingliang Zhao
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China
| | - Liangliang Wei
- State Key Laboratory of Urban Water Resources and Environment (SKLUWRE), Harbin 150090, China; School of Environment, Harbin Institute of Technology, Harbin 150090, China.
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9
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Chen CG, Nardi AN, Amadei A, D’Abramo M. Theoretical Modeling of Redox Potentials of Biomolecules. Molecules 2022; 27:molecules27031077. [PMID: 35164342 PMCID: PMC8838479 DOI: 10.3390/molecules27031077] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/21/2022] [Accepted: 01/25/2022] [Indexed: 11/28/2022] Open
Abstract
The estimation of the redox potentials of biologically relevant systems by means of theoretical-computational approaches still represents a challenge. In fact, the size of these systems typically does not allow a full quantum-mechanical treatment needed to describe electron loss/gain in such a complex environment, where the redox process takes place. Therefore, a number of different theoretical strategies have been developed so far to make the calculation of the redox free energy feasible with current computational resources. In this review, we provide a survey of such theoretical-computational approaches used in this context, highlighting their physical principles and discussing their advantages and limitations. Several examples of these approaches applied to the estimation of the redox potentials of both proteins and nucleic acids are described and critically discussed. Finally, general considerations on the most promising strategies are reported.
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Affiliation(s)
- Cheng Giuseppe Chen
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy; (C.G.C.); (A.N.N.)
| | | | - Andrea Amadei
- Department of Chemical and Technological Sciences, Tor Vergata University, 00133 Rome, Italy;
| | - Marco D’Abramo
- Department of Chemistry, Sapienza University of Rome, 00185 Rome, Italy; (C.G.C.); (A.N.N.)
- Correspondence:
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10
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McCuskey SR, Chatsirisupachai J, Zeglio E, Parlak O, Panoy P, Herland A, Bazan GC, Nguyen TQ. Current Progress of Interfacing Organic Semiconducting Materials with Bacteria. Chem Rev 2021; 122:4791-4825. [PMID: 34714064 DOI: 10.1021/acs.chemrev.1c00487] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Microbial bioelectronics require interfacing microorganisms with electrodes. The resulting abiotic/biotic platforms provide the basis of a range of technologies, including energy conversion and diagnostic assays. Organic semiconductors (OSCs) provide a unique strategy to modulate the interfaces between microbial systems and external electrodes, thereby improving the performance of these incipient technologies. In this review, we explore recent progress in the field on how OSCs, and related materials capable of charge transport, are being used within the context of microbial systems, and more specifically bacteria. We begin by examining the electrochemical communication modes in bacteria and the biological basis for charge transport. Different types of synthetic organic materials that have been designed and synthesized for interfacing and interrogating bacteria are discussed next, followed by the most commonly used characterization techniques for evaluating transport in microbial, synthetic, and hybrid systems. A range of applications is subsequently examined, including biological sensors and energy conversion systems. The review concludes by summarizing what has been accomplished so far and suggests future design approaches for OSC bioelectronics materials and technologies that hybridize characteristic properties of microbial and OSC systems.
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Affiliation(s)
- Samantha R McCuskey
- Department of Chemistry, National University of Singapore, Singapore 119077, Singapore
| | - Jirat Chatsirisupachai
- Center for Polymers and Organic Solids & Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Erica Zeglio
- Division of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 17177, Sweden
| | - Onur Parlak
- Dermatology and Venereology Division, Department of Medicine(Solna), Karolinska Institute, Stockholm 17177, Sweden.,AIMES Center of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, Stockholm 17177, Sweden
| | - Patchareepond Panoy
- Center for Polymers and Organic Solids & Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States.,Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology, Wangchan, Rayong 21210, Thailand
| | - Anna Herland
- Division of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 17177, Sweden.,AIMES Center of Integrated Medical and Engineering Sciences, Department of Neuroscience, Karolinska Institute, Stockholm 17177, Sweden
| | - Guillermo C Bazan
- Department of Chemistry, National University of Singapore, Singapore 119077, Singapore
| | - Thuc-Quyen Nguyen
- Center for Polymers and Organic Solids & Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
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11
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Multiple hops move electrons from bacteria to rocks. Proc Natl Acad Sci U S A 2021; 118:2115620118. [PMID: 34625473 DOI: 10.1073/pnas.2115620118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2021] [Indexed: 11/18/2022] Open
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12
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Ru X, Crane BR, Zhang P, Beratan DN. Why Do Most Aromatics Fail to Support Hole Hopping in the Cytochrome c Peroxidase-Cytochrome c Complex? J Phys Chem B 2021; 125:7763-7773. [PMID: 34235935 DOI: 10.1021/acs.jpcb.1c05064] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Electron transport through aromatic species (especially tryptophan and tyrosine) plays a central role in water splitting, redox signaling, oxidative damage protection, and bioenergetics. The cytochrome c peroxidase (CcP)-cytochrome c (Cc) complex (CcP:Cc) is used widely to study interprotein electron transfer (ET) mechanisms. Tryptophan 191 (Trp191) of CcP supports hole hopping charge recombination in the CcP:Cc complex. Experimental studies find that when Trp191 is substituted by tyrosine, phenylalanine, or redox-active aniline derivatives bound in the W191G cavity, enzymatic activity and charge recombination rates both decrease. Theoretical analysis of these CcP:Cc complexes finds that the ET kinetics depend strongly on the chemistry of the modified Trp site. The computed electronic couplings in the W191F and W191G species are orders of magnitude smaller than in the native protein, due largely to the absence of a hopping intermediate and the large tunneling distance. Small molecules bound in the W191G cavity are weakly coupled electronically to the Cc heme, and the structural disorder of the guest molecule in the binding pocket may contribute further to the lack of enzymatic activity. The couplings in W191Y are not substantially weakened compared to the native species, but the redox potential difference for tyrosine vs tryptophan oxidation accounts for the slower rate in the Tyr mutant. Thus, theoretical analysis explains why only the native Trp supports rapid hole hopping in the CcP:Cc complex. Favorable free energies and electronic couplings are essential for establishing an efficient hole hopping relay in this protein-protein complex.
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Affiliation(s)
- Xuyan Ru
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - Brian R Crane
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Peng Zhang
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States
| | - David N Beratan
- Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.,Department of Biochemistry, Duke University, Durham, North Carolina 27710, United States.,Department of Physics, Duke University, Durham, North Carolina 27708, United States
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13
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Controls on Interspecies Electron Transport and Size Limitation of Anaerobically Methane-Oxidizing Microbial Consortia. mBio 2021; 12:mBio.03620-20. [PMID: 33975943 PMCID: PMC8263020 DOI: 10.1128/mbio.03620-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
About 382 Tg yr−1 of methane rising through the seafloor is oxidized anaerobically (W. S. Reeburgh, Chem Rev 107:486–513, 2007, https://doi.org/10.1021/cr050362v), preventing it from reaching the atmosphere, where it acts as a strong greenhouse gas. Microbial consortia composed of anaerobic methanotrophic archaea and sulfate-reducing bacteria couple the oxidation of methane to the reduction of sulfate under anaerobic conditions via a syntrophic process. Recent experimental studies and modeling efforts indicate that direct interspecies electron transfer (DIET) is involved in this syntrophy. Here, we explore a fluorescent in situ hybridization-nanoscale secondary ion mass spectrometry data set of large, segregated anaerobic oxidation of methane (AOM) consortia that reveal a decline in metabolic activity away from the archaeal-bacterial interface and use a process-based model to identify the physiological controls on rates of AOM. Simulations reproducing the observational data reveal that ohmic resistance and activation loss are the two main factors causing the declining metabolic activity, where activation loss dominated at a distance of <8 μm. These voltage losses limit the maximum spatial distance between syntrophic partners with model simulations, indicating that sulfate-reducing bacterial cells can remain metabolically active up to ∼30 μm away from the archaeal-bacterial interface. Model simulations further predict that a hybrid metabolism that combines DIET with a small contribution of diffusive exchange of electron donors can offer energetic advantages for syntrophic consortia.
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14
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Intrinsic electronic conductivity of individual atomically resolved amyloid crystals reveals micrometer-long hole hopping via tyrosines. Proc Natl Acad Sci U S A 2021; 118:2014139118. [PMID: 33372136 DOI: 10.1073/pnas.2014139118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Proteins are commonly known to transfer electrons over distances limited to a few nanometers. However, many biological processes require electron transport over far longer distances. For example, soil and sediment bacteria transport electrons, over hundreds of micrometers to even centimeters, via putative filamentous proteins rich in aromatic residues. However, measurements of true protein conductivity have been hampered by artifacts due to large contact resistances between proteins and electrodes. Using individual amyloid protein crystals with atomic-resolution structures as a model system, we perform contact-free measurements of intrinsic electronic conductivity using a four-electrode approach. We find hole transport through micrometer-long stacked tyrosines at physiologically relevant potentials. Notably, the transport rate through tyrosines (105 s-1) is comparable to cytochromes. Our studies therefore show that amyloid proteins can efficiently transport charges, under ordinary thermal conditions, without any need for redox-active metal cofactors, large driving force, or photosensitizers to generate a high oxidation state for charge injection. By measuring conductivity as a function of molecular length, voltage, and temperature, while eliminating the dominant contribution of contact resistances, we show that a multistep hopping mechanism (composed of multiple tunneling steps), not single-step tunneling, explains the measured conductivity. Combined experimental and computational studies reveal that proton-coupled electron transfer confers conductivity; both the energetics of the proton acceptor, a neighboring glutamine, and its proximity to tyrosine influence the hole transport rate through a proton rocking mechanism. Surprisingly, conductivity increases 200-fold upon cooling due to higher availability of the proton acceptor by increased hydrogen bonding.
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15
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He X, Chadwick G, Jiménez Otero F, Orphan V, Meile C. Spatially Resolved Electron Transport through Anode‐Respiring
Geobacter sulfurreducens
Biofilms: Controls and Constraints. ChemElectroChem 2021. [DOI: 10.1002/celc.202100111] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Xiaojia He
- Department of Marine Sciences University of Georgia Athens GA USA
| | - Grayson Chadwick
- Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA
| | | | - Victoria Orphan
- Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA
| | - Christof Meile
- Department of Marine Sciences University of Georgia Athens GA USA
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16
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Zhao J, Li F, Cao Y, Zhang X, Chen T, Song H, Wang Z. Microbial extracellular electron transfer and strategies for engineering electroactive microorganisms. Biotechnol Adv 2020; 53:107682. [PMID: 33326817 DOI: 10.1016/j.biotechadv.2020.107682] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 11/04/2020] [Accepted: 12/09/2020] [Indexed: 11/27/2022]
Abstract
Electroactive microorganisms (EAMs) are ubiquitous in nature and have attracted considerable attention as they can be used for energy recovery and environmental remediation via their extracellular electron transfer (EET) capabilities. Although the EET mechanisms of Shewanella and Geobacter have been rigorously investigated and are well characterized, much less is known about the EET mechanisms of other microorganisms. For EAMs, efficient EET is crucial for the sustainable economic development of bioelectrochemical systems (BESs). Currently, the low efficiency of EET remains a key factor in limiting the development of BESs. In this review, we focus on the EET mechanisms of different microorganisms, (i.e., bacteria, fungi, and archaea). In addition, we describe in detail three engineering strategies for improving the EET ability of EAMs: (1) enhancing transmembrane electron transport via cytochrome protein channels; (2) accelerating electron transport via electron shuttle synthesis and transmission; and (3) promoting the microbe-electrode interface reaction via regulating biofilm formation. At the end of this review, we look to the future, with an emphasis on the cross-disciplinary integration of systems biology and synthetic biology to build high-performance EAM systems.
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Affiliation(s)
- Juntao Zhao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBioResearch Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Feng Li
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBioResearch Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Yingxiu Cao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBioResearch Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Xinbo Zhang
- Joint Research Centre for Protective Infrastructure Technology and Environmental Green Bioprocess, Department of Environmental and Municipal Engineering, Tianjin Chengjian University, Tianjin 300384, People's Republic of China
| | - Tao Chen
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBioResearch Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Hao Song
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBioResearch Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China
| | - Zhiwen Wang
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), SynBioResearch Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, People's Republic of China.
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17
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Futera Z, Ide I, Kayser B, Garg K, Jiang X, van Wonderen JH, Butt JN, Ishii H, Pecht I, Sheves M, Cahen D, Blumberger J. Coherent Electron Transport across a 3 nm Bioelectronic Junction Made of Multi-Heme Proteins. J Phys Chem Lett 2020; 11:9766-9774. [PMID: 33142062 PMCID: PMC7681787 DOI: 10.1021/acs.jpclett.0c02686] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Multi-heme cytochromes (MHCs) are fascinating proteins used by bacterial organisms to shuttle electrons within, between, and out of their cells. When placed in solid-state electronic junctions, MHCs support temperature-independent currents over several nanometers that are 3 orders of magnitude higher compared to other redox proteins of similar size. To gain molecular-level insight into their astonishingly high conductivities, we combine experimental photoemission spectroscopy with DFT+Σ current-voltage calculations on a representative Gold-MHC-Gold junction. We find that conduction across the dry, 3 nm long protein occurs via off-resonant coherent tunneling, mediated by a large number of protein valence-band orbitals that are strongly delocalized over heme and protein residues. This picture is profoundly different from the electron hopping mechanism induced electrochemically or photochemically under aqueous conditions. Our results imply that the current output in solid-state junctions can be even further increased in resonance, for example, by applying a gate voltage, thus allowing a quantum jump for next-generation bionanoelectronic devices.
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Affiliation(s)
- Zdenek Futera
- Faculty
of Science, University of South Bohemia, Branisovska 1760, 370 05 Ceske Budejovice, Czech Republic
- Department
of Physics and Astronomy, University College
London, Gower Street, London WC1E
6BT, U.K.
| | - Ichiro Ide
- Graduate
School of Science and Engineering, Chiba
University, Chiba, Japan
| | - Ben Kayser
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovot, Israel
| | - Kavita Garg
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovot, Israel
| | - Xiuyun Jiang
- Department
of Physics and Astronomy, University College
London, Gower Street, London WC1E
6BT, U.K.
| | - Jessica H. van Wonderen
- School
of Chemistry, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
| | - Julea N. Butt
- School
of Chemistry, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
| | - Hisao Ishii
- Graduate
School of Science and Engineering, Chiba
University, Chiba, Japan
| | - Israel Pecht
- Department
of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | - Mordechai Sheves
- Department
of Organic Chemistry, Weizmann Institute
of Science, Rehovot, Israel
| | - David Cahen
- Department
of Materials and Interfaces, Weizmann Institute
of Science, Rehovot, Israel
| | - Jochen Blumberger
- Department
of Physics and Astronomy, University College
London, Gower Street, London WC1E
6BT, U.K.
- (J.B.)
. Phone: ++44-(0)20-7679-4373. Fax: ++44-(0)20-7679-7145
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18
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Jiang X, van Wonderen JH, Butt JN, Edwards MJ, Clarke TA, Blumberger J. Which Multi-Heme Protein Complex Transfers Electrons More Efficiently? Comparing MtrCAB from Shewanella with OmcS from Geobacter. J Phys Chem Lett 2020; 11:9421-9425. [PMID: 33104365 DOI: 10.1021/acs.jpclett.0c02842] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Microbial nanowires are fascinating biological structures that allow bacteria to transport electrons over micrometers for reduction of extracellular substrates. It was recently established that the nanowires of both Shewanella and Geobacter are made of multi-heme proteins; but, while Shewanella employs the 20-heme protein complex MtrCAB, Geobacter uses a redox polymer made of the hexa-heme protein OmcS, begging the question as to which protein architecture is more efficient in terms of long-range electron transfer. Using a multiscale computational approach we find that OmcS supports electron flows about an order of magnitude higher than MtrCAB due to larger heme-heme electronic couplings and better insulation of hemes from the solvent. We show that heme side chains are an essential structural element in both protein complexes, accelerating rate-limiting electron tunnelling steps up to 1000-fold. Our results imply that the alternating stacked/T-shaped heme arrangement present in both protein complexes may be an evolutionarily convergent design principle permitting efficient electron transfer over very long distances.
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Affiliation(s)
- Xiuyun Jiang
- Department of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom
| | - Jessica H van Wonderen
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Julea N Butt
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Marcus J Edwards
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Thomas A Clarke
- School of Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Jochen Blumberger
- Department of Physics and Astronomy and Thomas Young Centre, University College London, London WC1E 6BT, United Kingdom
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19
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Ptushenko VV. Electric Cables of Living Cells. II. Bacterial Electron Conductors. BIOCHEMISTRY (MOSCOW) 2020; 85:955-965. [PMID: 33045956 DOI: 10.1134/s0006297920080118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The concept of "electric cables" involved in bioenergetic processes of a living cell was proposed half a century ago [Skulachev, V. P. (1971) Curr. Top. Bioenerg., Elsevier, pp. 127-190]. For many decades, only cell membrane structures have been considered as probable pathways for the electric current, namely, for the transfer of transmembrane electrochemical potential. However, the last ten to fifteen years have brought the discovery of bacterial "electric cables" of a new type. In 2005, "nanowires" conducting electric current over distances of tens of micrometers were discovered in metal- and sulphate-reducing bacteria [Reguera, G. et al. (2005) Nature, 435, pp. 1098-1101]. The next five years have witnessed the discovery of microbial electric currents over centimeter distances [Nielsen, L. P. et al. (2010) Nature, 463, 1071-1074]. This new group of bacteria allowing electric currents to flow over macroscopic distances was later called cable bacteria. Nanowires and conductive structures of cable bacteria serve to solve a special problem of membrane bioenergetics: they connect two redox half-reactions. In other words, unlike membrane "cables", their function is electron transfer in the course of oxidative phosphorylation for the generation of membrane energy rather than of the end-product. The most surprising is the protein nature of these cables (at least of some of them) indicated by recent data, since no protein wires for the long-distance electron transport had been previously known in living systems.
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Affiliation(s)
- V V Ptushenko
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia. .,Emanuel Institute of Biochemical Physics of the Russian Academy of Sciences, Moscow, 119334, Russia
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20
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Derr JB, Tamayo J, Clark JA, Morales M, Mayther MF, Espinoza EM, Rybicka-Jasińska K, Vullev VI. Multifaceted aspects of charge transfer. Phys Chem Chem Phys 2020; 22:21583-21629. [PMID: 32785306 PMCID: PMC7544685 DOI: 10.1039/d0cp01556c] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Charge transfer and charge transport are by far among the most important processes for sustaining life on Earth and for making our modern ways of living possible. Involving multiple electron-transfer steps, photosynthesis and cellular respiration have been principally responsible for managing the energy flow in the biosphere of our planet since the Great Oxygen Event. It is impossible to imagine living organisms without charge transport mediated by ion channels, or electron and proton transfer mediated by redox enzymes. Concurrently, transfer and transport of electrons and holes drive the functionalities of electronic and photonic devices that are intricate for our lives. While fueling advances in engineering, charge-transfer science has established itself as an important independent field, originating from physical chemistry and chemical physics, focusing on paradigms from biology, and gaining momentum from solar-energy research. Here, we review the fundamental concepts of charge transfer, and outline its core role in a broad range of unrelated fields, such as medicine, environmental science, catalysis, electronics and photonics. The ubiquitous nature of dipoles, for example, sets demands on deepening the understanding of how localized electric fields affect charge transfer. Charge-transfer electrets, thus, prove important for advancing the field and for interfacing fundamental science with engineering. Synergy between the vastly different aspects of charge-transfer science sets the stage for the broad global impacts that the advances in this field have.
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Affiliation(s)
- James B Derr
- Department of Biochemistry, University of California, Riverside, CA 92521, USA.
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21
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Roy S, Xie O, Dorval Courchesne N. Challenges in engineering conductive protein fibres: Disentangling the knowledge. CAN J CHEM ENG 2020. [DOI: 10.1002/cjce.23836] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Sophia Roy
- Department of Chemical Engineering McGill University Montréal Québec Canada
| | - Oliver Xie
- Department of Chemical Engineering McGill University Montréal Québec Canada
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22
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Huang J, Zarzycki J, Gunner MR, Parson WW, Kern JF, Yano J, Ducat DC, Kramer DM. Mesoscopic to Macroscopic Electron Transfer by Hopping in a Crystal Network of Cytochromes. J Am Chem Soc 2020; 142:10459-10467. [DOI: 10.1021/jacs.0c02729] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Jingcheng Huang
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - Jan Zarzycki
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - M. R. Gunner
- Department of Physics, City College of New York, New York, New York 10031, United States
| | - William W. Parson
- Department of Biochemistry, University of Washington, Seattle, Washington 98195, United States
| | - Jan F. Kern
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Daniel C. Ducat
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
| | - David M. Kramer
- DOE-Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824, United States
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23
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Onuchic JN, Rubtsov IV, Therien MJ. Tribute to David N. Beratan. J Phys Chem B 2020; 124:3437-3440. [DOI: 10.1021/acs.jpcb.0c02606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Abstract
The Wiedemann-Franz (WF) law is a fundamental result in solid-state physics that relates the thermal and electrical conductivity of a metal. It is derived from the predominant transport mechanism in metals: the motion of quasi-free charge-carrying particles. Here, an equivalent WF relationship is developed for molecular systems in which charge carriers are moving not as free particles but instead hop between redox sites. We derive a concise analytical relationship between the electrical and thermal conductivity generated by electron hopping in molecular systems and find that the linear temperature dependence of their ratio as expressed in the standard WF law is replaced by a linear dependence on the nuclear reorganization energy associated with the electron hopping process. The robustness of the molecular WF relation is confirmed by examining the conductance properties of a paradigmatic molecular junction. This result opens a new way to analyze conductivity in molecular systems, with possible applications advancing the design of molecular technologies that derive their function from electrical and/or thermal conductance.
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Affiliation(s)
- Galen T Craven
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - Abraham Nitzan
- Department of Chemistry , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
- School of Chemistry , Tel Aviv University , Tel Aviv 69978 , Israel
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25
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Valianti S, Skourtis SS. Observing Donor-to-Acceptor Electron-Transfer Rates and the Marcus Inverted Parabola in Molecular Junctions. J Phys Chem B 2019; 123:9641-9653. [DOI: 10.1021/acs.jpcb.9b07371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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26
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Meysman FJR, Cornelissen R, Trashin S, Bonné R, Martinez SH, van der Veen J, Blom CJ, Karman C, Hou JL, Eachambadi RT, Geelhoed JS, Wael KD, Beaumont HJE, Cleuren B, Valcke R, van der Zant HSJ, Boschker HTS, Manca JV. A highly conductive fibre network enables centimetre-scale electron transport in multicellular cable bacteria. Nat Commun 2019; 10:4120. [PMID: 31511526 PMCID: PMC6739318 DOI: 10.1038/s41467-019-12115-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 08/19/2019] [Indexed: 11/25/2022] Open
Abstract
Biological electron transport is classically thought to occur over nanometre distances, yet recent studies suggest that electrical currents can run along centimetre-long cable bacteria. The phenomenon remains elusive, however, as currents have not been directly measured, nor have the conductive structures been identified. Here we demonstrate that cable bacteria conduct electrons over centimetre distances via highly conductive fibres embedded in the cell envelope. Direct electrode measurements reveal nanoampere currents in intact filaments up to 10.1 mm long (>2000 adjacent cells). A network of parallel periplasmic fibres displays a high conductivity (up to 79 S cm−1), explaining currents measured through intact filaments. Conductance rapidly declines upon exposure to air, but remains stable under vacuum, demonstrating that charge transfer is electronic rather than ionic. Our finding of a biological structure that efficiently guides electrical currents over long distances greatly expands the paradigm of biological charge transport and could enable new bio-electronic applications. Cable bacteria’ form long multicellular filaments that can transfer electrical currents over centimetre-long distances. Here, Meysman et al. show that the electrical currents run along highly conductive fibres embedded in the cell envelope, and charge transfer is electronic rather than ionic.
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Affiliation(s)
- Filip J R Meysman
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Wilrijk, Belgium. .,Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ, Delft, The Netherlands.
| | - Rob Cornelissen
- X-LAB, Hasselt University, Agoralaan D, B-3590, Diepenbeek, Belgium
| | - Stanislav Trashin
- AXES Research group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerpen, Belgium
| | - Robin Bonné
- X-LAB, Hasselt University, Agoralaan D, B-3590, Diepenbeek, Belgium
| | - Silvia Hidalgo Martinez
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Wilrijk, Belgium
| | - Jasper van der Veen
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Technical University Delft, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
| | - Carsten J Blom
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Cheryl Karman
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Wilrijk, Belgium.,AXES Research group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerpen, Belgium
| | - Ji-Ling Hou
- X-LAB, Hasselt University, Agoralaan D, B-3590, Diepenbeek, Belgium
| | | | - Jeanine S Geelhoed
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Wilrijk, Belgium
| | - Karolien De Wael
- AXES Research group, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, B-2020, Antwerpen, Belgium
| | - Hubertus J E Beaumont
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Bart Cleuren
- Theoretical Physics, Hasselt University, Agoralaan D, B-3590, Diepenbeek, Belgium
| | - Roland Valcke
- Molecular and Physical Plant Physiology, Hasselt University, Agoralaan D, B-3590, Diepenbeek, Belgium
| | - Herre S J van der Zant
- Department of Quantum Nanoscience, Kavli Institute of Nanoscience, Technical University Delft, Lorentzweg 1, 2628 CJ, Delft, The Netherlands
| | - Henricus T S Boschker
- Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610, Wilrijk, Belgium.,Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629HZ, Delft, The Netherlands
| | - Jean V Manca
- X-LAB, Hasselt University, Agoralaan D, B-3590, Diepenbeek, Belgium
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27
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Ru X, Zhang P, Beratan DN. Assessing Possible Mechanisms of Micrometer-Scale Electron Transfer in Heme-Free Geobacter sulfurreducens Pili. J Phys Chem B 2019; 123:5035-5047. [PMID: 31095388 DOI: 10.1021/acs.jpcb.9b01086] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The electrically conductive pili of Geobacter sulfurreducens are of both fundamental and practical interest. They facilitate extracellular and interspecies electron transfer (ET) and also provide an electrical interface between living and nonliving systems. We examine the possible mechanisms of G. sulfurreducens electron transfer in regimes ranging from incoherent to coherent transport. For plausible ET parameters, electron transfer in G. sulfurreducens bacterial nanowires mediated only by the protein is predicted to be dominated by incoherent hopping between phenylalanine (Phe) and tyrosine (Tyr) residues that are 3 to 4 Å apart, where Phe residues in the hopping pathways may create delocalized "islands." This mechanism could be accessible in the presence of strong oxidants that are capable of oxidizing Phe and Tyr residues. We also examine the physical requirements needed to sustain biological respiration via nanowires. We find that the hopping regimes with ET rates on the order of 108 s-1 between Phe islands and Tyr residues, and conductivities on the order of mS/cm, can support ET fluxes that are compatible with cellular respiration rates, although sustaining this delocalization in the heterogeneous protein environment may be challenging. Computed values of fully coherent electron fluxes through the pili are orders of magnitude too low to support microbial respiration. We suggest experimental probes of the transport mechanism based on mutant studies to examine the roles of aromatic amino acids and yet to be identified redox cofactors.
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Affiliation(s)
- Xuyan Ru
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States
| | - Peng Zhang
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States
| | - David N Beratan
- Department of Chemistry , Duke University , Durham , North Carolina 27708 , United States.,Department of Biochemistry , Duke University , Durham , North Carolina 27710 , United States.,Department of Physics , Duke University , Durham , North Carolina 27708 , United States
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28
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Abstract
The family Geobacteraceae, with its only valid genus Geobacter, comprises deltaproteobacteria ubiquitous in soil, sediments, and subsurface environments where metal reduction is an active process. Research for almost three decades has provided novel insights into environmental processes and biogeochemical reactions not previously known to be carried out by microorganisms. At the heart of the environmental roles played by Geobacter bacteria is their ability to integrate redox pathways and regulatory checkpoints that maximize growth efficiency with electron donors derived from the decomposition of organic matter while respiring metal oxides, particularly the often abundant oxides of ferric iron. This metabolic specialization is complemented by versatile metabolic reactions, respiratory chains, and sensory networks that allow specific members to adaptively respond to environmental cues to integrate organic and inorganic contaminants in their oxidative and reductive metabolism, respectively. Thus, Geobacteraceae are important members of the microbial communities that degrade hydrocarbon contaminants under iron-reducing conditions and that contribute, directly or indirectly, to the reduction of radionuclides, toxic metals, and oxidized species of nitrogen. Their ability to produce conductive pili as nanowires for discharging respiratory electrons to solid-phase electron acceptors and radionuclides, or for wiring cells in current-harvesting biofilms highlights the unique physiological traits that make these organisms attractive biological platforms for bioremediation, bioenergy, and bioelectronics application. Here we review some of the most notable physiological features described in Geobacter species since the first model representatives were recovered in pure culture. We provide a historical account of the environmental research that has set the foundation for numerous physiological studies and the laboratory tools that had provided novel insights into the role of Geobacter in the functioning of microbial communities from pristine and contaminated environments. We pay particular attention to latest research, both basic and applied, that has served to expand the field into new directions and to advance interdisciplinary knowledge. The electrifying physiology of Geobacter, it seems, is alive and well 30 years on.
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Abstract
The availability of renewable energy technologies is increasing dramatically across the globe thanks to their growing maturity. However, large scale electrical energy storage and retrieval will almost certainly be a required in order to raise the penetration of renewable sources into the grid. No present energy storage technology has the perfect combination of high power and energy density, low financial and environmental cost, lack of site restrictions, long cycle and calendar lifespan, easy materials availability, and fast response time. Engineered electroactive microbes could address many of the limitations of current energy storage technologies by enabling rewired carbon fixation, a process that spatially separates reactions that are normally carried out together in a photosynthetic cell and replaces the least efficient with non-biological equivalents. If successful, this could allow storage of renewable electricity through electrochemical or enzymatic fixation of carbon dioxide and subsequent storage as carbon-based energy storage molecules including hydrocarbons and non-volatile polymers at high efficiency. In this article we compile performance data on biological and non-biological component choices for rewired carbon fixation systems and identify pressing research and engineering challenges.
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Reguera G. Microbial nanowires and electroactive biofilms. FEMS Microbiol Ecol 2019; 94:5000162. [PMID: 29931163 DOI: 10.1093/femsec/fiy086] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 05/11/2018] [Indexed: 12/14/2022] Open
Abstract
Geobacter bacteria are the only microorganisms known to produce conductive appendages or pili to electronically connect cells to extracellular electron acceptors such as iron oxide minerals and uranium. The conductive pili also promote cell-cell aggregation and the formation of electroactive biofilms. The hallmark of these electroactive biofilms is electronic heterogeneity, mediated by coordinated interactions between the conductive pili and matrix-associated cytochromes. Collectively, the matrix-associated electron carriers discharge respiratory electrons from cells in multilayered biofilms to electron-accepting surfaces such as iron oxide coatings and electrodes poised at a metabolically oxidizable potential. The presence of pilus nanowires in the electroactive biofilms also promotes the immobilization and reduction of soluble metals, even when present at toxic concentrations. This review summarizes current knowledge about the composition of the electroactive biofilm matrix and the mechanisms that allow the wired Geobacter biofilms to generate electrical currents and participate in metal redox transformations.
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Affiliation(s)
- Gemma Reguera
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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Kinetics of trifurcated electron flow in the decaheme bacterial proteins MtrC and MtrF. Proc Natl Acad Sci U S A 2019; 116:3425-3430. [PMID: 30755526 DOI: 10.1073/pnas.1818003116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The bacterium Shewanella oneidensis has evolved a sophisticated electron transfer (ET) machinery to export electrons from the cytosol to extracellular space during extracellular respiration. At the heart of this process are decaheme proteins of the Mtr pathway, MtrC and MtrF, located at the external face of the outer bacterial membrane. Crystal structures have revealed that these proteins bind 10 c-type hemes arranged in the peculiar shape of a staggered cross that trifurcates the electron flow, presumably to reduce extracellular substrates while directing electrons to neighboring multiheme cytochromes at either side along the membrane. Especially intriguing is the design of the heme junctions trifurcating the electron flow: they are made of coplanar and T-shaped heme pair motifs with relatively large and seemingly unfavorable tunneling distances. Here, we use electronic structure calculations and molecular simulations to show that the side chains of the heme rings, in particular the cysteine linkages inserting in the space between coplanar and T-shaped heme pairs, strongly enhance electronic coupling in these two motifs. This results in an [Formula: see text]-fold speedup of ET steps at heme junctions that would otherwise be rate limiting. The predicted maximum electron flux through the solvated proteins is remarkably similar for all possible flow directions, suggesting that MtrC and MtrF shuttle electrons with similar efficiency and reversibly in directions parallel and orthogonal to the outer membrane. No major differences in the ET properties of MtrC and MtrF are found, implying that the different expression levels of the two proteins during extracellular respiration are not related to redox function.
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Abstract
The corpus of electron transfer (ET) theory provides considerable power to describe the kinetics and dynamics of electron flow at the nanoscale. How is it, then, that nucleic acid (NA) ET continues to surprise, while protein-mediated ET is relatively free of mechanistic bombshells? I suggest that this difference originates in the distinct electronic energy landscapes for the two classes of reactions. In proteins, the donor/acceptor-to-bridge energy gap is typically several-fold larger than in NAs. NA ET can access tunneling, hopping, and resonant transport among the bases, and fluctuations can enable switching among mechanisms; protein ET is restricted to tunneling among redox active cofactors and, under strongly oxidizing conditions, a few privileged amino acid side chains. This review aims to provide conceptual unity to DNA and protein ET reaction mechanisms. The establishment of a unified mechanistic framework enabled the successful design of NA experiments that switch electronic coherence effects on and off for ET processes on a length scale of multiple nanometers and promises to provide inroads to directing and detecting charge flow in soft-wet matter.
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Affiliation(s)
- David N Beratan
- Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708, USA; .,Department of Biochemistry, Duke University, Durham, North Carolina 27710, USA
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Arinda T, Philipp LA, Rehnlund D, Edel M, Chodorski J, Stöckl M, Holtmann D, Ulber R, Gescher J, Sturm-Richter K. Addition of Riboflavin-Coupled Magnetic Beads Increases Current Production in Bioelectrochemical Systems via the Increased Formation of Anode-Biofilms. Front Microbiol 2019; 10:126. [PMID: 30804910 PMCID: PMC6370747 DOI: 10.3389/fmicb.2019.00126] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/21/2019] [Indexed: 11/17/2022] Open
Abstract
Shewanella oneidensis is one of the best-understood model organisms for extracellular electron transfer. Endogenously produced and exported flavin molecules seem to play an important role in this process and mediate the connection between respiratory enzymes on the cell surface and the insoluble substrate by acting as electron shuttle and cytochrome-bound cofactor. Consequently, the addition of riboflavin to a bioelectrochemical system (BES) containing S. oneidensis cells as biocatalyst leads to a strong current increase. Still, an external application of riboflavin to increase current production in continuously operating BESs does not seem to be applicable due to the constant washout of the soluble flavin compound. In this study, we developed a recyclable electron shuttle to overcome the limitation of mediator addition to BES. Riboflavin was coupled to magnetic beads that can easily be recycled from the medium. The effect on current production and cell distribution in a BES as well as the recovery rate and the stability of the beads was investigated. The addition of synthesized beads leads to a more than twofold higher current production, which was likely caused by increased biofilm production. Moreover, 90% of the flavin-coupled beads could be recovered from the BESs using a magnetic separator.
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Affiliation(s)
- Tutut Arinda
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Laura-Alina Philipp
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - David Rehnlund
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Miriam Edel
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Jonas Chodorski
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Markus Stöckl
- Electrochemistry, DECHEMA-Forschungsinstitut, Frankfurt, Germany
| | - Dirk Holtmann
- Industrial Biotechnology, DECHEMA-Forschungsinstitut, Frankfurt, Germany
| | - Roland Ulber
- Chair of Bioprocess Engineering, Technical University of Kaiserslautern, Kaiserslautern, Germany
| | - Johannes Gescher
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany.,Institute for Biological Interfaces, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Katrin Sturm-Richter
- Institute for Applied Biosciences, Department of Applied Biology, Karlsruhe Institute of Technology, Karlsruhe, Germany
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Craven GT, He D, Nitzan A. Electron-Transfer-Induced Thermal and Thermoelectric Rectification. PHYSICAL REVIEW LETTERS 2018; 121:247704. [PMID: 30608770 DOI: 10.1103/physrevlett.121.247704] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Indexed: 06/09/2023]
Abstract
Controlling the direction and magnitude of both heat and electronic currents using rectifiers has significant implications for the advancement of molecular circuit design. In order to facilitate the implementation of new transport phenomena in such molecular structures, we examine thermal and thermoelectric rectification effects that are induced by an electron transfer process that occurs across a temperature gradient between molecules. Historically, the only known heat conduction mechanism able to generate thermal rectification in purely molecular environments is phononic heat transport. Here, we show that electron transfer between molecular sites with different local temperatures can also generate a thermal rectification effect and that electron hopping through molecular bridges connecting metal leads at different temperatures gives rise to asymmetric Seebeck effects, that is, thermoelectric rectification, in molecular junctions.
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Affiliation(s)
- Galen T Craven
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Dahai He
- Department of Physics and Jiujiang Research Institute, Xiamen University, Xiamen 361005, China
| | - Abraham Nitzan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- School of Chemistry, Tel Aviv University, Tel Aviv 69978, Israel
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Electron transfer and transport through multi-heme proteins: recent progress and future directions. Curr Opin Chem Biol 2018; 47:24-31. [DOI: 10.1016/j.cbpa.2018.06.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 06/24/2018] [Indexed: 12/20/2022]
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Krylov A, Windus TL, Barnes T, Marin-Rimoldi E, Nash JA, Pritchard B, Smith DGA, Altarawy D, Saxe P, Clementi C, Crawford TD, Harrison RJ, Jha S, Pande VS, Head-Gordon T. Perspective: Computational chemistry software and its advancement as illustrated through three grand challenge cases for molecular science. J Chem Phys 2018; 149:180901. [DOI: 10.1063/1.5052551] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Anna Krylov
- Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA
| | - Theresa L. Windus
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA
| | - Taylor Barnes
- Molecular Sciences Software Institute, Blacksburg, Virginia 24061, USA
| | | | - Jessica A. Nash
- Molecular Sciences Software Institute, Blacksburg, Virginia 24061, USA
| | | | | | - Doaa Altarawy
- Molecular Sciences Software Institute, Blacksburg, Virginia 24061, USA
| | - Paul Saxe
- Molecular Sciences Software Institute, Blacksburg, Virginia 24061, USA
| | - Cecilia Clementi
- Department of Chemistry and Center for Theoretical Biological Physics, Rice University, 6100 Main Street, Houston, Texas 77005, USA
- Department of Mathematics and Computer Science, Freie Universitt Berlin, Arnimallee 6, 14195 Berlin, Germany
| | | | - Robert J. Harrison
- Institute for Advanced Computational Science, Stony Brook University, Stony Brook, New York 11794, USA
| | - Shantenu Jha
- Electrical and Computer Engineering, Rutgers The State University of New Jersey, Piscataway, New Jersey 08854, USA
| | - Vijay S. Pande
- Department of Bioengineering, Stanford University, Stanford, California 94305, USA
| | - Teresa Head-Gordon
- Department of Chemistry, Department of Bioengineering, Department of Chemical and Biomolecular Engineering, Pitzer Center for Theoretical Chemistry, University of California, Berkeley, California 94720, USA
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Garg K, Ghosh M, Eliash T, van Wonderen JH, Butt JN, Shi L, Jiang X, Zdenek F, Blumberger J, Pecht I, Sheves M, Cahen D. Direct evidence for heme-assisted solid-state electronic conduction in multi-heme c-type cytochromes. Chem Sci 2018; 9:7304-7310. [PMID: 30294419 PMCID: PMC6166575 DOI: 10.1039/c8sc01716f] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/26/2018] [Indexed: 12/27/2022] Open
Abstract
Multi-heme cytochrome c (Cytc) proteins are key for transferring electrons out of cells, to enable intracellular oxidation to proceed in the absence of O2. In these proteins most of the hemes are arranged in a linear array suggesting a facile path for electronic conduction. To test this, we studied solvent-free electron transport across two multi-heme Cytc-type proteins: MtrF (deca-heme Cytc) and STC (tetra-heme Cytc). Transport is measured across monolayers of these proteins in a solid state configuration between Au electrodes. Both proteins showed 1000× higher conductance than single heme, or heme-free proteins, but similar conductance to monolayers of conjugated organics. Conductance is found to be temperature-independent (320-80 K), suggesting tunneling as the transport mechanism. This mechanism is consistent with I-V curves modelling, results of which could be interpreted by having protein-electrode coupling as rate limiting, rather than transport within the proteins.
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Affiliation(s)
- Kavita Garg
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - Mihir Ghosh
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - Tamar Eliash
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - Jessica H van Wonderen
- School of Chemistry , School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Julea N Butt
- School of Chemistry , School of Biological Sciences , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK
| | - Liang Shi
- Department of Biological Sciences and Technology , School of Environmental Sciences , China University of Geosciences , Wuhan , China 430074
| | - Xiuyun Jiang
- Department of Physics and Astronomy and Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , UK
| | - Futera Zdenek
- Department of Physics and Astronomy and Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , UK
| | - Jochen Blumberger
- Department of Physics and Astronomy and Thomas Young Centre , University College London , Gower Street , London WC1E 6BT , UK
| | - Israel Pecht
- Department of Immunology , Weizmann Institute of Science , Rehovot , Israel
| | - Mordechai Sheves
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot , Israel .
| | - David Cahen
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovot , Israel .
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38
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Chong GW, Karbelkar AA, El-Naggar MY. Nature's conductors: what can microbial multi-heme cytochromes teach us about electron transport and biological energy conversion? Curr Opin Chem Biol 2018; 47:7-17. [PMID: 30015234 DOI: 10.1016/j.cbpa.2018.06.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 06/04/2018] [Indexed: 10/28/2022]
Abstract
Microorganisms can acquire energy from the environment by extending their electron transport chains to external solid electron donors or acceptors. This process, known as extracellular electron transfer (EET), is now being heavily pursued for wiring microbes to electrodes in bioelectrochemical renewable energy technologies. Recent studies highlight the crucial role of multi-heme cytochromes in facilitating biotic-abiotic EET both for cellular electron export and uptake. Here we explore progress in understanding the range and function of these biological electron conduits in the context of fuel-to-electricity and electricity-to-bioproduct conversion. We also highlight emerging topics, including the role of multi-heme cytochromes in inter-species electron transfer and in inspiring the design and synthesis of a new generation of protein-based bioelectronic components.
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Affiliation(s)
- Grace W Chong
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, USA
| | - Amruta A Karbelkar
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089-1062, USA
| | - Mohamed Y El-Naggar
- Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, USA; Department of Chemistry, University of Southern California, Los Angeles, CA 90089-1062, USA; Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484, USA.
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Wang T, Zhang D, Dai L, Dong B, Dai X. Magnetite Triggering Enhanced Direct Interspecies Electron Transfer: A Scavenger for the Blockage of Electron Transfer in Anaerobic Digestion of High-Solids Sewage Sludge. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7160-7169. [PMID: 29782790 DOI: 10.1021/acs.est.8b00891] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
At present, high-solids anaerobic digestion of sewage sludge has drawn great attention due to the superiority of its small land area footprint and low energy consumption. However, a high organic loading rate may cause acids accumulation and ammonia inhibition, thus leading to an inhibited pseudo-steady state in which electron transfer through interspecies hydrogen transfer (IHT) between acetogens and methanogens is blocked. In this study, adding 50 mg/g TS (total solid) magnetite clearly reduced the accumulation of short-chain fatty acids and accelerated methane production by 26.6%. As demonstrated, the individual processes of anaerobic digestion could not be improved by magnetite when methanogenesis was interrupted. Analyzing stable carbon isotopes and investigating the methanogenesis pathways using acetate and H2/CO2 as substrates together proved that direct interspecies electron transfer (DIET) was enhanced by magnetite. Metatranscriptomic analysis and determination of key enzymes showed that IHT could be partially substituted by enhanced DIET, and acetate-dependent methanogenesis was improved after the blockage of electron transfer was scavenged. Additionally, the expression of both pili and c-type cytochromes was found to decrease, indicating that magnetite could replace their roles for efficient electron transfer between acetogens and methanogens; thus, a robust chain of electron transfer was established.
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Affiliation(s)
- Tao Wang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering , Tongji University , 1239 Siping Road , Shanghai 200092 , China
| | - Dong Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering , Tongji University , 1239 Siping Road , Shanghai 200092 , China
| | - Lingling Dai
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering , Tongji University , 1239 Siping Road , Shanghai 200092 , China
| | - Bin Dong
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering , Tongji University , 1239 Siping Road , Shanghai 200092 , China
| | - Xiaohu Dai
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering , Tongji University , 1239 Siping Road , Shanghai 200092 , China
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40
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Reguera G. Harnessing the power of microbial nanowires. Microb Biotechnol 2018; 11:979-994. [PMID: 29806247 PMCID: PMC6201914 DOI: 10.1111/1751-7915.13280] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/13/2018] [Accepted: 04/22/2018] [Indexed: 12/13/2022] Open
Abstract
The reduction of iron oxide minerals and uranium in model metal reducers in the genus Geobacter is mediated by conductive pili composed primarily of a structurally divergent pilin peptide that is otherwise recognized, processed and assembled in the inner membrane by a conserved Type IVa pilus apparatus. Electronic coupling among the peptides is promoted upon assembly, allowing the discharge of respiratory electrons at rates that greatly exceed the rates of cellular respiration. Harnessing the unique properties of these conductive appendages and their peptide building blocks in metal bioremediation will require understanding of how the pilins assemble to form a protein nanowire with specialized sites for metal immobilization. Also important are insights into how cells assemble the pili to make an electroactive matrix and grow on electrodes as biofilms that harvest electrical currents from the oxidation of waste organic substrates. Genetic engineering shows promise to modulate the properties of the peptide building blocks, protein nanowires and current‐harvesting biofilms for various applications. This minireview discusses what is known about the pilus material properties and reactions they catalyse and how this information can be harnessed in nanotechnology, bioremediation and bioenergy applications.
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Affiliation(s)
- Gemma Reguera
- Department of Microbiology and Molecular Genetics, Michigan State University, 567 Wilson Rd., Rm. 6190, East Lansing, MI, 48824, USA
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Ultrastructure of Shewanella oneidensis MR-1 nanowires revealed by electron cryotomography. Proc Natl Acad Sci U S A 2018; 115:E3246-E3255. [PMID: 29555764 DOI: 10.1073/pnas.1718810115] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacterial nanowires have garnered recent interest as a proposed extracellular electron transfer (EET) pathway that links the bacterial electron transport chain to solid-phase electron acceptors away from the cell. Recent studies showed that Shewanella oneidensis MR-1 produces outer membrane (OM) and periplasmic extensions that contain EET components and hinted at their possible role as bacterial nanowires. However, their fine structure and distribution of cytochrome electron carriers under native conditions remained unclear, making it difficult to evaluate the potential electron transport (ET) mechanism along OM extensions. Here, we report high-resolution images of S. oneidensis OM extensions, using electron cryotomography (ECT). We developed a robust method for fluorescence light microscopy imaging of OM extension growth on electron microscopy grids and used correlative light and electron microscopy to identify and image the same structures by ECT. Our results reveal that S. oneidensis OM extensions are dynamic chains of interconnected outer membrane vesicles (OMVs) with variable dimensions, curvature, and extent of tubulation. Junction densities that potentially stabilize OMV chains are seen between neighboring vesicles in cryotomograms. By comparing wild type and a cytochrome gene deletion mutant, our ECT results provide the likely positions and packing of periplasmic and outer membrane proteins consistent with cytochromes. Based on the observed cytochrome packing density, we propose a plausible ET path along the OM extensions involving a combination of direct hopping and cytochrome diffusion. A mean-field calculation, informed by the observed ECT cytochrome density, supports this proposal by revealing ET rates on par with a fully packed cytochrome network.
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Microbial nanowires - Electron transport and the role of synthetic analogues. Acta Biomater 2018; 69:1-30. [PMID: 29357319 DOI: 10.1016/j.actbio.2018.01.007] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 01/07/2018] [Accepted: 01/09/2018] [Indexed: 02/07/2023]
Abstract
Electron transfer is central to cellular life, from photosynthesis to respiration. In the case of anaerobic respiration, some microbes have extracellular appendages that can be utilised to transport electrons over great distances. Two model organisms heavily studied in this arena are Shewanella oneidensis and Geobacter sulfurreducens. There is some debate over how, in particular, the Geobacter sulfurreducens nanowires (formed from pilin nanofilaments) are capable of achieving the impressive feats of natural conductivity that they display. In this article, we outline the mechanisms of electron transfer through delocalised electron transport, quantum tunnelling, and hopping as they pertain to biomaterials. These are described along with existing examples of the different types of conductivity observed in natural systems such as DNA and proteins in order to provide context for understanding the complexities involved in studying the electron transport properties of these unique nanowires. We then introduce some synthetic analogues, made using peptides, which may assist in resolving this debate. Microbial nanowires and the synthetic analogues thereof are of particular interest, not just for biogeochemistry, but also for the exciting potential bioelectronic and clinical applications as covered in the final section of the review. STATEMENT OF SIGNIFICANCE Some microbes have extracellular appendages that transport electrons over vast distances in order to respire, such as the dissimilatory metal-reducing bacteria Geobacter sulfurreducens. There is significant debate over how G. sulfurreducens nanowires are capable of achieving the impressive feats of natural conductivity that they display: This mechanism is a fundamental scientific challenge, with important environmental and technological implications. Through outlining the techniques and outcomes of investigations into the mechanisms of such protein-based nanofibrils, we provide a platform for the general study of the electronic properties of biomaterials. The implications are broad-reaching, with fundamental investigations into electron transfer processes in natural and biomimetic materials underway. From these studies, applications in the medical, energy, and IT industries can be developed utilising bioelectronics.
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Bostick CD, Mukhopadhyay S, Pecht I, Sheves M, Cahen D, Lederman D. Protein bioelectronics: a review of what we do and do not know. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:026601. [PMID: 29303117 DOI: 10.1088/1361-6633/aa85f2] [Citation(s) in RCA: 136] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We review the status of protein-based molecular electronics. First, we define and discuss fundamental concepts of electron transfer and transport in and across proteins and proposed mechanisms for these processes. We then describe the immobilization of proteins to solid-state surfaces in both nanoscale and macroscopic approaches, and highlight how different methodologies can alter protein electronic properties. Because immobilizing proteins while retaining biological activity is crucial to the successful development of bioelectronic devices, we discuss this process at length. We briefly discuss computational predictions and their connection to experimental results. We then summarize how the biological activity of immobilized proteins is beneficial for bioelectronic devices, and how conductance measurements can shed light on protein properties. Finally, we consider how the research to date could influence the development of future bioelectronic devices.
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Affiliation(s)
- Christopher D Bostick
- Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV 26506, United States of America. Institute for Genomic Medicine, Columbia University Medical Center, New York, NY 10032, United States of America
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Grebenko A, Dremov V, Barzilovich P, Bubis A, Sidoruk K, Voeikova T, Gagkaeva Z, Chernov T, Korostylev E, Gorshunov B, Motovilov K. Impedance spectroscopy of single bacterial nanofilament reveals water-mediated charge transfer. PLoS One 2018; 13:e0191289. [PMID: 29351332 PMCID: PMC5774759 DOI: 10.1371/journal.pone.0191289] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/02/2018] [Indexed: 11/19/2022] Open
Abstract
For decades respiratory chain and photosystems were the main firing field of the studies devoted to mechanisms of electron transfer in proteins. The concept of conjugated lateral electron and transverse proton transport during cellular respiration and photosynthesis, which was formulated in the beginning of 1960-s, has been confirmed by thousands of experiments. However, charge transfer in recently discovered bacterial nanofilaments produced by various electrogenic bacteria is regarded currently outside of electron and proton conjugation concept. Here we report the new study of charge transfer within nanofilaments produced by Shewanella oneidensis MR-1 conducted in atmosphere of different relative humidity (RH). We utilize impedance spectroscopy and DC (direct current) transport measurements to find out the peculiarities of conductivity and Raman spectroscopy to analyze the nanofilaments' composition. Data analysis demonstrates that apparent conductivity of nanofilaments has crucial sensitivity to humidity and contains several components including one with unusual behavior which we assign to electron transport. We demonstrate that in the case of Shewanella oneidensis MR-1 charge transfer within these objects is strongly mediated by water. Basing on current data analysis of conductivity we conclude that the studied filaments of Shewanella oneidensis MR-1 are capable of hybrid (conjugated) electron and ion conductivity.
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Affiliation(s)
- Artem Grebenko
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
- Institute of Solid State Physics (RAS), Academician Osipyana street 2, Chernogolovka, Russia
| | - Vyacheslav Dremov
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
- Institute of Solid State Physics (RAS), Academician Osipyana street 2, Chernogolovka, Russia
| | - Petr Barzilovich
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
- Institute of Problems of Chemical Physics (RAS), Academician Semenov avenue 1, Chernogolovka, Russia
| | - Anton Bubis
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
- Institute of Solid State Physics (RAS), Academician Osipyana street 2, Chernogolovka, Russia
| | - Konstantin Sidoruk
- Scientific Center of Russian Federation Research Institute for Genetics and Selection of Industrial Microorganisms, 1-st Dorozhniy pr., 1, Moscow, Russia
| | - Tatiyana Voeikova
- Scientific Center of Russian Federation Research Institute for Genetics and Selection of Industrial Microorganisms, 1-st Dorozhniy pr., 1, Moscow, Russia
| | - Zarina Gagkaeva
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
| | - Timur Chernov
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
- Institute of Problems of Chemical Physics (RAS), Academician Semenov avenue 1, Chernogolovka, Russia
| | - Evgeny Korostylev
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
| | - Boris Gorshunov
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
| | - Konstantin Motovilov
- Moscow Institute of Physics and Technology, Institute lane 9, Dolgoprudny, Russian Federation
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46
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Lebedev N, Griva I, Blom A, Tender LM. Effect of iron doping on protein molecular conductance. Phys Chem Chem Phys 2018; 20:14072-14081. [DOI: 10.1039/c8cp00656c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study analyzes the role of Fe in electron transfer through non-heme iron-containing proteins.
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Affiliation(s)
- Nikolai Lebedev
- Center for Bio-Molecular Science and Engineering
- U.S. Naval Research Laboratory
- Washington
- USA
| | - Igor Griva
- Department of Mathematical Sciences and Center for Simulation and Modeling
- George Mason University
- Fairfax
- USA
| | | | - Leonard M. Tender
- Center for Bio-Molecular Science and Engineering
- U.S. Naval Research Laboratory
- Washington
- USA
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Jiang X, Futera Z, Ali ME, Gajdos F, von Rudorff GF, Carof A, Breuer M, Blumberger J. Cysteine Linkages Accelerate Electron Flow through Tetra-Heme Protein STC. J Am Chem Soc 2017; 139:17237-17240. [DOI: 10.1021/jacs.7b08831] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Xiuyun Jiang
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Zdenek Futera
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Md. Ehesan Ali
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Fruzsina Gajdos
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Guido F. von Rudorff
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Antoine Carof
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Marian Breuer
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
| | - Jochen Blumberger
- Department
of Physics and Astronomy, University College London, London WC1E 6BT, U.K
- Institute
for Advanced Study, Technische Universität München, Lichtenbergstrasse
2a, D-85748 Garching, Germany
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48
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Xiao Y, Zhang E, Zhang J, Dai Y, Yang Z, Christensen HEM, Ulstrup J, Zhao F. Extracellular polymeric substances are transient media for microbial extracellular electron transfer. SCIENCE ADVANCES 2017; 3:e1700623. [PMID: 28695213 PMCID: PMC5498105 DOI: 10.1126/sciadv.1700623] [Citation(s) in RCA: 312] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/18/2017] [Indexed: 05/19/2023]
Abstract
Microorganisms exploit extracellular electron transfer (EET) in growth and information exchange with external environments or with other cells. Every microbial cell is surrounded by extracellular polymeric substances (EPS). Understanding the roles of three-dimensional (3D) EPS in EET is essential in microbiology and microbial exploitation for mineral bio-respiration, pollutant conversion, and bioenergy production. We have addressed these challenges by comparing pure and EPS-depleted samples of three representative electrochemically active strains viz Gram-negative Shewanella oneidensis MR-1, Gram-positive Bacillus sp. WS-XY1, and yeast Pichia stipites using technology from electrochemistry, spectroscopy, atomic force microscopy, and microbiology. Voltammetry discloses redox signals from cytochromes and flavins in intact MR-1 cells, whereas stronger signals from cytochromes and additional signals from both flavins and cytochromes are found after EPS depletion. Flow cytometry and fluorescence microscopy substantiated by N-acetylglucosamine and electron transport system activity data showed less than 1.5% cell damage after EPS extraction. The electrochemical differences between normal and EPS-depleted cells therefore originate from electrochemical species in cell walls and EPS. The 35 ± 15-nm MR-1 EPS layer is also electrochemically active itself, with cytochrome electron transfer rate constants of 0.026 and 0.056 s-1 for intact MR-1 and EPS-depleted cells, respectively. This surprisingly small rate difference suggests that molecular redox species at the core of EPS assist EET. The combination of all the data with electron transfer analysis suggests that electron "hopping" is the most likely molecular mechanism for electrochemical electron transfer through EPS.
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Affiliation(s)
- Yong Xiao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Enhua Zhang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
- Key Laboratory of Environmental Biology and Pollution Control, College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | - Jingdong Zhang
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Youfen Dai
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Zhaohui Yang
- Key Laboratory of Environmental Biology and Pollution Control, College of Environmental Science and Engineering, Hunan University, Changsha 410082, China
| | | | - Jens Ulstrup
- Department of Chemistry, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Feng Zhao
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
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Amdursky N, Wang X, Meredith P, Riley DJ, Payne DJ, Bradley DDC, Stevens MM. Electron Hopping Across Hemin-Doped Serum Albumin Mats on Centimeter-Length Scales. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1700810. [PMID: 28561988 PMCID: PMC5788260 DOI: 10.1002/adma.201700810] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 03/30/2017] [Indexed: 05/22/2023]
Abstract
Exploring long-range electron transport across protein assemblies is a central interest in both the fundamental research of biological processes and the emerging field of bioelectronics. This work examines the use of serum-albumin-based freestanding mats as macroscopic electron mediators in bioelectronic devices. In particular, this study focuses on how doping the protein mat with hemin improves charge-transport. It is demonstrated that doping can increase conductivity 40-fold via electron hopping between adjacent hemin molecules, resulting in the highest measured conductance for a protein-based material yet reported, and transport over centimeter length scales. The use of distance-dependent AC impedance and DC current-voltage measurements allows the contribution from electron hopping between adjacent hemin molecules to be isolated. Because the hemin-doped serum albumin mats have both biocompatibility and fabrication simplicity, they should be applicable to a range of bioelectronic devices of varying sizes, configurations, and applications.
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Affiliation(s)
- Nadav Amdursky
- Department of MaterialsDepartment of Bioengineering and Institute of Biomedical EngineeringImperial College LondonLondonSW7 2AZUK
- Schulich Faculty of ChemistryTechnion – Israel Institute of TechnologyHaifa3200003Israel
| | - Xuhua Wang
- Department of Physics and Centre for Plastic ElectronicsImperial College LondonLondonSW7 2AZUK
| | - Paul Meredith
- Department of PhysicsSwansea UniversitySingleton ParkSwanseaSA2 8PPWalesUK
| | - D. Jason Riley
- Department of MaterialsImperial College LondonLondonSW7 2AZUK
| | - David J. Payne
- Department of MaterialsImperial College LondonLondonSW7 2AZUK
| | - Donal D. C. Bradley
- Department of Physics and Centre for Plastic ElectronicsImperial College LondonLondonSW7 2AZUK
- Departments of Engineering Science & Physics Mathematical, Physical and Life Sciences DivisionUniversity of OxfordOxfordOX1 3PDUK
| | - Molly M. Stevens
- Department of MaterialsDepartment of Bioengineering and Institute of Biomedical EngineeringImperial College LondonLondonSW7 2AZUK
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50
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Okamoto A, Tokunou Y, Kalathil S, Hashimoto K. Proton Transport in the Outer‐Membrane Flavocytochrome Complex Limits the Rate of Extracellular Electron Transport. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201704241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Akihiro Okamoto
- Global Research Center for Environment and Energy based on Nanomaterials Science National Institute for Material Science 1-1 Namiki, Tsukuba Ibaraki 305-0044 Japan
| | - Yoshihide Tokunou
- Department of Applied Chemistry The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Shafeer Kalathil
- Department of Applied Chemistry The University of Tokyo 7-3-1 Hongo, Bunkyo-ku Tokyo 113-8656 Japan
| | - Kazuhito Hashimoto
- Global Research Center for Environment and Energy based on Nanomaterials Science National Institute for Material Science 1-1 Namiki, Tsukuba Ibaraki 305-0044 Japan
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