1
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Garg K, Futera Z, Wu X, Jeong Y, Chiu R, Pisharam VC, Ha TQ, Aragonès AC, van Wonderen JH, Butt JN, Blumberger J, Díez-Pérez I. Shallow conductance decay along the heme array of a single tetraheme protein wire. Chem Sci 2024; 15:12326-12335. [PMID: 39118640 PMCID: PMC11304805 DOI: 10.1039/d4sc01366b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 06/24/2024] [Indexed: 08/10/2024] Open
Abstract
Multiheme cytochromes (MHCs) are the building blocks of highly conductive micrometre-long supramolecular wires found in so-called electrical bacteria. Recent studies have revealed that these proteins possess a long supramolecular array of closely packed heme cofactors along the main molecular axis alternating between perpendicular and stacking configurations (TST = T-shaped, stacked, T-shaped). While TST arrays have been identified as the likely electron conduit, the mechanisms of outstanding long-range charge transport observed in these structures remain unknown. Here we study charge transport on individual small tetraheme cytochromes (STCs) containing a single TST heme array. Individual STCs are trapped in a controllable nanoscale tunnelling gap. By modulating the tunnelling gap separation, we are able to selectively probe four different electron pathways involving 1, 2, 3 and 4 heme cofactors, respectively, leading to the determination of the electron tunnelling decay constant along the TST heme motif. Conductance calculations of selected single-STC junctions are in excellent agreement with experiments and suggest a mechanism of electron tunnelling with shallow length decay constant through an individual STC. These results demonstrate that an individual TST motif supporting electron tunnelling might contribute to a tunnelling-assisted charge transport diffusion mechanism in larger TST associations.
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Affiliation(s)
- Kavita Garg
- Department of Chemistry, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, Britannia House 7 Trinity Street London SE1 1DB UK
| | - Zdenek Futera
- Faculty of Science, University of South Bohemia Branisovska 1760 370 05 Ceske Budejovice Czech Republic
| | - Xiaojing Wu
- Department of Physics and Astronomy, Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
| | - Yongchan Jeong
- Department of Chemistry, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, Britannia House 7 Trinity Street London SE1 1DB UK
| | - Rachel Chiu
- School of Chemistry, School of Biological Sciences, University of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Varun Chittari Pisharam
- Department of Chemistry, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, Britannia House 7 Trinity Street London SE1 1DB UK
| | - Tracy Q Ha
- Department of Chemistry, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, Britannia House 7 Trinity Street London SE1 1DB UK
| | - Albert C Aragonès
- Departament de Ciència de Materials i Química Física, Universitat de Barcelona, Institut de Química Teòrica i Computacional (IQTC) Marti i Franquès 1 08028 Barcelona Spain
| | - 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
| | - Jochen Blumberger
- Department of Physics and Astronomy, Thomas Young Centre, University College London Gower Street London WC1E 6BT UK
| | - Ismael Díez-Pérez
- Department of Chemistry, Faculty of Natural, Mathematical & Engineering Sciences, King's College London, Britannia House 7 Trinity Street London SE1 1DB UK
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2
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Zhang Y, Liang H, Qi P, Xu Z, Fei H, Guo C. Deciphering the Roles of Interfacial Amino Acids in Inter-Protein Charge Transport. NANO LETTERS 2024; 24:4178-4185. [PMID: 38552164 DOI: 10.1021/acs.nanolett.4c00164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Elucidating charge transport (CT) through proteins is critical for gaining insights into ubiquitous CT chain reactions in biological systems and developing high-performance bioelectronic devices. While intra-protein CT has been extensively studied, crucial knowledge about inter-protein CT via interfacial amino acids is still absent due to the structural complexity. Herein, by loading cytochrome c (Cyt c) on well-defined peptide self-assembled monolayers to mimic the protein-protein interface, we provide a precisely controlled platform for identifying the roles of interfacial amino acids in solid-state CT via peptide-Cyt c junctions. The terminal amino acid of peptides serves as a fine-tuning factor for both the interfacial interaction between peptides and Cyt c and the immobilized Cyt c orientation, resulting in a nearly 10-fold difference in current through peptide-Cyt c junctions with varied asymmetry. This work provides a valuable platform for studying CT across proteins and contributes to the understanding of fundamental principles governing inter-protein CT.
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Affiliation(s)
- Yongkang Zhang
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Han Liang
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Pan Qi
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Zhongchen Xu
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Houguo Fei
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
| | - Cunlan Guo
- College of Chemistry and Molecular Sciences, Wuhan University, 299 Bayi Road, Wuhan, Hubei 430072, China
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3
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Bera S, Fereiro JA, Saxena SK, Chryssikos D, Majhi K, Bendikov T, Sepunaru L, Ehre D, Tornow M, Pecht I, Vilan A, Sheves M, Cahen D. Near-Temperature-Independent Electron Transport Well beyond Expected Quantum Tunneling Range via Bacteriorhodopsin Multilayers. J Am Chem Soc 2023; 145. [PMID: 37933117 PMCID: PMC10655127 DOI: 10.1021/jacs.3c09120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/08/2023]
Abstract
A key conundrum of biomolecular electronics is efficient electron transport (ETp) through solid-state junctions up to 10 nm, often without temperature activation. Such behavior challenges known charge transport mechanisms, especially via nonconjugated molecules such as proteins. Single-step, coherent quantum-mechanical tunneling proposed for ETp across small protein, 2-3 nm wide junctions, but it is problematic for larger proteins. Here we exploit the ability of bacteriorhodopsin (bR), a well-studied, 4-5 nm long membrane protein, to assemble into well-defined single and multiple bilayers, from ∼9 to 60 nm thick, to investigate ETp limits as a function of junction width. To ensure sufficient signal/noise, we use large area (∼10-3 cm2) Au-protein-Si junctions. Photoemission spectra indicate a wide energy separation between electrode Fermi and the nearest protein-energy levels, as expected for a polymer of mostly saturated components. Junction currents decreased exponentially with increasing junction width, with uniquely low length-decay constants (0.05-0.5 nm-1). Remarkably, even for the widest junctions, currents are nearly temperature-independent, completely so below 160 K. While, among other things, the lack of temperature-dependence excludes, hopping as a plausible mechanism, coherent quantum-mechanical tunneling over 60 nm is physically implausible. The results may be understood if ETp is limited by injection into one of the contacts, followed by more efficient charge propagation across the protein. Still, the electrostatics of the protein films further limit the number of charge carriers injected into the protein film. How electron transport across dozens of nanometers of protein layers is more efficient than injection defines a riddle, requiring further study.
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Affiliation(s)
- Sudipta Bera
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jerry A. Fereiro
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
- School
of Chemistry, Indian Institute of Science
Education and Research, Thiruvananthapuram 695551, Kerala, India
| | - Shailendra K. Saxena
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
- Department
of Physics and Nanotechnology, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chennai 603203, Tamil
Nadu, India
| | - Domenikos Chryssikos
- Molecular
Electronics, Technical University of Munich, 85748 Garching, Germany
- Fraunhofer
Institute for Electronic Microsystems and Solid State Technologies
(EMFT), 80686 München, Germany
| | - Koushik Majhi
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Tatyana Bendikov
- Department
of Chemical Research Support, Weizmann Institute
of Science, Rehovot 7610001, Israel
| | - Lior Sepunaru
- Department
of Chemistry and Biochemistry, University
of California, Santa
Barbara, California 93106, United States
| | - David Ehre
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Marc Tornow
- Molecular
Electronics, Technical University of Munich, 85748 Garching, Germany
- Fraunhofer
Institute for Electronic Microsystems and Solid State Technologies
(EMFT), 80686 München, Germany
| | - Israel Pecht
- Department
of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ayelet Vilan
- Department
of Chemical and Biological Physics Weizmann
Institute of Science, Rehovot 7610001, Israel
| | - Mordechai Sheves
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - David Cahen
- Department
of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 7610001, Israel
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4
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Papp E, Vattay G, Romero-Muñiz C, Zotti LA, Fereiro JA, Sheves M, Cahen D. Experimental Data Confirm Carrier-Cascade Model for Solid-State Conductance across Proteins. J Phys Chem B 2023; 127:1728-1734. [PMID: 36790863 DOI: 10.1021/acs.jpcb.2c07946] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
The finding that electronic conductance across ultrathin protein films between metallic electrodes remains nearly constant from room temperature to just a few degrees Kelvin has posed a challenge. We show that a model based on a generalized Landauer formula explains the nearly constant conductance and predicts an Arrhenius-like dependence for low temperatures. A critical aspect of the model is that the relevant activation energy for conductance is either the difference between the HOMO and HOMO-1 or the LUMO+1 and LUMO energies instead of the HOMO-LUMO gap of the proteins. Analysis of experimental data confirms the Arrhenius-like law and allows us to extract the activation energies. We then calculate the energy differences with advanced DFT methods for proteins used in the experiments. Our main result is that the experimental and theoretical activation energies for these three different proteins and three differently prepared solid-state junctions match nearly perfectly, implying the mechanism's validity.
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Affiliation(s)
- Eszter Papp
- Department of Physics of Complex Systems, Eötvös Loránd University, Egyetem tér 1-3., H-1053 Budapest, Hungary
| | - Gábor Vattay
- Department of Physics of Complex Systems, Eötvös Loránd University, Egyetem tér 1-3., H-1053 Budapest, Hungary
| | - Carlos Romero-Muñiz
- Departamento de Física Aplicada I, Universidad de Sevilla, E-41012 Seville, Spain
| | - Linda A Zotti
- Departamento de Física Teórica de la Materia Condensada and IFIMAC, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Jerry A Fereiro
- School of Chemistry, Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram - 695551 Kerala, India
| | - Mordechai Sheves
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - David Cahen
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, 76100 Rehovot, Israel
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5
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Gupta N, Karuppannan SK, Pasula RR, Vilan A, Martin J, Xu W, May EM, Pike AR, Astier HPA, Salim T, Lim S, Nijhuis CA. Temperature-Dependent Coherent Tunneling across Graphene-Ferritin Biomolecular Junctions. ACS APPLIED MATERIALS & INTERFACES 2022; 14:44665-44675. [PMID: 36148983 PMCID: PMC9542697 DOI: 10.1021/acsami.2c11263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/08/2022] [Indexed: 06/16/2023]
Abstract
Understanding the mechanisms of charge transport (CT) across biomolecules in solid-state devices is imperative to realize biomolecular electronic devices in a predictive manner. Although it is well-accepted that biomolecule-electrode interactions play an essential role, it is often overlooked. This paper reveals the prominent role of graphene interfaces with Fe-storing proteins in the net CT across their tunnel junctions. Here, ferritin (AfFtn-AA) is adsorbed on the graphene by noncovalent amine-graphene interactions confirmed with Raman spectroscopy. In contrast to junctions with metal electrodes, graphene has a vanishing density of states toward its intrinsic Fermi level ("Dirac point"), which increases away from the Fermi level. Therefore, the amount of charge carriers is highly sensitive to temperature and electrostatic charging (induced doping), as deduced from a detailed analysis of CT as a function of temperature and iron loading. Remarkably, the temperature dependence can be fully explained within the coherent tunneling regime due to excitation of hot carriers. Graphene is not only demonstrated as an alternative platform to study CT across biomolecular tunnel junctions, but it also opens rich possibilities in employing interface electrostatics in tuning CT behavior.
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Affiliation(s)
- Nipun
Kumar Gupta
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
- Centre
for Advanced 2D Materials, National University
of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Senthil Kumar Karuppannan
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Rupali Reddy Pasula
- School
of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore
| | - Ayelet Vilan
- Department
of Chemical and Biological Physics, Weizmann
Institute of Science, Rehovot 76100, Israel
| | - Jens Martin
- Centre
for Advanced 2D Materials, National University
of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Wentao Xu
- Centre
for Advanced 2D Materials, National University
of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Esther Maria May
- Chemistry-School
of Natural and Environmental Sciences, Newcastle
University, Newcastle
upon Tyne NE1 7RU, U.K.
| | - Andrew R. Pike
- School
of
Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Hippolyte P. A.
G. Astier
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Teddy Salim
- School
of
Materials Science and Engineering, Nanyang
Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Sierin Lim
- School
of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore
| | - Christian A. Nijhuis
- Department
of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
- Centre
for Advanced 2D Materials, National University
of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
- Hybrid
Materials for Opto-Electronics Group, Department of Molecules and
Materials, MESA+ Institute for Nanotechnology and Centre for Brain-Inspired
Nano Systems, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands
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6
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Zhang B, Ryan E, Wang X, Song W, Lindsay S. Electronic Transport in Molecular Wires of Precisely Controlled Length Built from Modular Proteins. ACS NANO 2022; 16:1671-1680. [PMID: 35029115 PMCID: PMC9279515 DOI: 10.1021/acsnano.1c10830] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
DNA molecular wires have been studied extensively because of the ease with which molecules of controlled length and composition can be synthesized. The same has not been true for proteins. Here, we have synthesized and studied a series of consensus tetratricopeptide repeat (CTPR) proteins, spanning 4 to 20 nm in length, in increments of 4 nm. For lengths in excess of 6 nm, their conductance exceeds that of the canonical molecular wire, oligo(phenylene-ethylenene), because of the more gradual decay of conductance with length in the protein. We show that, while the conductance decay fits an exponential (characteristic of quantum tunneling) and not a linear increase of resistance with length (characteristic of hopping transport), it is also accounted for by a square-law dependence on length (characteristic of weakly driven hopping). Measurements of the energy dependence of the decay length rule out the quantum tunneling case. A resonance in the carrier injection energy shows that allowed states in the protein align with the Fermi energy of the electrodes. Both the energy of these states and the long-range of hopping suggest that the reorganization induced by hole formation is greatly reduced inside the protein. We outline a model for calculating the molecular-electronic properties of proteins.
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Affiliation(s)
- Bintian Zhang
- Biodesign Institute, Arizona State University, Tempe, AZ 85281
| | - Eathen Ryan
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
| | - Xu Wang
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
| | - Weisi Song
- Biodesign Institute, Arizona State University, Tempe, AZ 85281
| | - Stuart Lindsay
- Biodesign Institute, Arizona State University, Tempe, AZ 85281
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85281
- Department of Physics, Arizona State University, Tempe, AZ 85281
- Corresponding Author: Stuart Lindsay: Phone 480 205 6432
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7
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Gupta R, Jash P, Sachan P, Bayat A, Singh V, Mondal PC. Electrochemical Potential‐Driven High‐Throughput Molecular Electronic and Spintronic Devices: From Molecules to Applications. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202104724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ritu Gupta
- Department of Chemistry Indian Institute of Technology Kanpur Uttar Pradesh 208016 India
| | - Priyajit Jash
- Department of Chemistry Indian Institute of Technology Kanpur Uttar Pradesh 208016 India
| | - Pradeep Sachan
- Department of Chemistry Indian Institute of Technology Kanpur Uttar Pradesh 208016 India
| | - Akhtar Bayat
- Laboratoire Photonique Numérique et Nanosciences, UMR 5298 Université de Bordeaux 33400 Talence France
| | - Vikram Singh
- Department of Chemistry and National Science Research Institute Korea Advanced Institute of Science and Technology 291 Daehak-ro, Yuseong-gu Daejeon 34141 Republic of Korea
| | - Prakash Chandra Mondal
- Department of Chemistry Indian Institute of Technology Kanpur Uttar Pradesh 208016 India
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8
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Cahen D, Pecht I, Sheves M. What Can We Learn from Protein-Based Electron Transport Junctions? J Phys Chem Lett 2021; 12:11598-11603. [PMID: 34852460 PMCID: PMC8647078 DOI: 10.1021/acs.jpclett.1c02446] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Affiliation(s)
- David Cahen
- Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Israel Pecht
- Weizmann Institute of Science, Rehovot 7610001, Israel
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9
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Gupta R, Jash P, Sachan P, Bayat A, Singh V, Mondal PC. Electrochemical Potential-Driven High-Throughput Molecular Electronic and Spintronic Devices: From Molecules to Applications. Angew Chem Int Ed Engl 2021; 60:26904-26921. [PMID: 34313372 DOI: 10.1002/anie.202104724] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Indexed: 01/25/2023]
Abstract
Molecules are fascinating candidates for constructing tunable and electrically conducting devices by the assembly of either a single molecule or an ensemble of molecules between two electrical contacts followed by current-voltage (I-V) analysis, which is often termed "molecular electronics". Recently, there has been also an upsurge of interest in spin-based electronics or spintronics across the molecules, which offer additional scope to create ultrafast responsive devices with less power consumption and lower heat generation using the intrinsic spin property rather than electronic charge. Researchers have been exploring this idea of utilizing organic molecules, organometallics, coordination complexes, polymers, and biomolecules (proteins, enzymes, oligopeptides, DNA) in integrating molecular electronics and spintronics devices. Although several methods exist to prepare molecular thin-films on suitable electrodes, the electrochemical potential-driven technique has emerged as highly efficient. In this Review we describe recent advances in the electrochemical potential driven growth of nanometric various molecular films on technologically relevant substrates, including non-magnetic and magnetic electrodes to investigate the stimuli-responsive charge and spin transport phenomena.
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Affiliation(s)
- Ritu Gupta
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, India
| | - Priyajit Jash
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, India
| | - Pradeep Sachan
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, India
| | - Akhtar Bayat
- Laboratoire Photonique Numérique et Nanosciences, UMR 5298, Université de Bordeaux, 33400, Talence, France
| | - Vikram Singh
- Department of Chemistry and National Science Research Institute, Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Prakash Chandra Mondal
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, 208016, India
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10
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Berselli G, Gimenez A, O’Connor A, Keyes TE. Robust Photoelectric Biomolecular Switch at a Microcavity-Supported Lipid Bilayer. ACS APPLIED MATERIALS & INTERFACES 2021; 13:29158-29169. [PMID: 34121400 PMCID: PMC8289237 DOI: 10.1021/acsami.1c06798] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/01/2021] [Indexed: 05/08/2023]
Abstract
Biomolecular devices based on photo-responsive proteins have been widely proposed for medical, electrical, and energy storage and production applications. Also, bacteriorhodopsin (bR) has been extensively applied in such prospective devices as a robust photo addressable proton pump. As it is a membrane protein, in principle, it should function most efficiently when reconstituted into a fully fluid lipid bilayer, but in many model membranes, lateral fluidity of the membrane and protein is sacrificed for electrochemical addressability because of the need for an electroactive surface. Here, we reported a biomolecular photoactive device based on light-activated proton pump, bR, reconstituted into highly fluidic microcavity-supported lipid bilayers (MSLBs) on functionalized gold and polydimethylsiloxane cavity array substrates. The integrity of reconstituted bR at the MSLBs along with the lipid bilayer formation was evaluated by fluorescence lifetime correlation spectroscopy, yielding a protein lateral diffusion coefficient that was dependent on the bR concentration and consistent with the Saffman-Delbrück model. The photoelectrical properties of bR-MSLBs were evaluated from the photocurrent signal generated by bR under continuous and transient light illumination. The optimal conditions for a self-sustaining photoelectrical switch were determined in terms of protein concentration, pH, and light switch frequency of activation. Overall, a significant increase in the transient current was observed for lipid bilayers containing approximately 0.3 mol % bR with a measured photo-current of 250 nA/cm2. These results demonstrate that the platforms provide an appropriate lipid environment to support the proton pump, enabling its efficient operation. The bR-reconstituted MSLB model serves both as a platform to study the protein in a highly addressable biomimetic environment and as a demonstration of reconstitution of seven-helix receptors into MSLBs, opening the prospect of reconstitution of related membrane proteins including G-protein-coupled receptors on these versatile biomimetic substrates.
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Affiliation(s)
- Guilherme
B. Berselli
- School of Chemical Sciences, National
Centre for Sensor Research, Dublin City
University, Dublin D09 FW22, Ireland
| | - Aurélien
V. Gimenez
- School of Chemical Sciences, National
Centre for Sensor Research, Dublin City
University, Dublin D09 FW22, Ireland
| | - Alexandra O’Connor
- School of Chemical Sciences, National
Centre for Sensor Research, Dublin City
University, Dublin D09 FW22, Ireland
| | - Tia E. Keyes
- School of Chemical Sciences, National
Centre for Sensor Research, Dublin City
University, Dublin D09 FW22, Ireland
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11
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Fereiro JA, Pecht I, Sheves M, Cahen D. Inelastic Electron Tunneling Spectroscopic Analysis of Bias-Induced Structural Changes in a Solid-State Protein Junction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2021; 17:e2008218. [PMID: 33783130 DOI: 10.1002/smll.202008218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/10/2021] [Indexed: 05/25/2023]
Abstract
A central issue in protein electronics is how far the structural stability of the protein is preserved under the very high electrical field that it will experience once a bias voltage is applied. This question is studied on the redox protein Azurin in the solid-state Au/protein/Au junction by monitoring protein vibrations during current transport under applied bias, up to ≈1 GV m-1 , by electrical detection of inelastic electron transport effects. Characteristic vibrational modes, such as CH stretching, amide (NH) bending, and AuS (of the bonds that connect the protein to an Au electrode), are not found to change noticeably up to 1.0 V. At >1.0 V, the NH bending and CH stretching inelastic features have disappeared, while the AuS features persist till ≈2 V, i.e., the proteins remain Au bound. Three possible causes for the disappearance of the NH and CH inelastic features at high bias, namely, i) resonance transport, ii) metallic filament formation, and iii) bond rupture leading to structural changes in the protein are proposed and tested. The results support the last option and indicate that spectrally resolved inelastic features can serve to monitor in operando structural stability of biological macromolecules while they serve as electronic current conduit.
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Affiliation(s)
- Jerry A Fereiro
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Israel Pecht
- Department of Immunology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Mordechai Sheves
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - David Cahen
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, 7610001, Israel
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12
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The Role of Metal Ions in the Electron Transport through Azurin-Based Junctions. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11093732] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We studied the coherent electron transport through metal–protein–metal junctions based on a blue copper azurin, in which the copper ion was replaced by three different metal ions (Co, Ni and Zn). Our results show that neither the protein structure nor the transmission at the Fermi level change significantly upon metal replacement. The discrepancy with previous experimental observations suggests that the transport mechanism taking place in these types of junctions is probably not fully coherent.
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13
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Alvarez AB, Pino M, Petersen SB, Fidelio GD. Stitching together a nm thick peptide-based semiconductor sheet using UV light. Colloids Surf B Biointerfaces 2021; 203:111734. [PMID: 33836369 DOI: 10.1016/j.colsurfb.2021.111734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/11/2021] [Accepted: 03/26/2021] [Indexed: 11/24/2022]
Abstract
Langmuir monolayer allows for a two-dimensional nano-scale organization of amphiphilic molecules. We have adapted this technique to measure lateral and transverse conductivity in confined peptide nanosheets for the first time. We reported that two retro-isomers amphipathic peptides form stable monolayers showing a semiconductor-like behavior. Both peptides exhibit the same hydrophobicity and surface stability. They differ in the lateral conductivity and current-voltage due to the asymmetric peptide bond backbone orientation at the interface. Both peptides contain several tyrosines allowing the lateral crosslinking in neighboring molecules induced by UVB. UVB-light induces changes in the lateral conductivity and current-voltage behavior as well as monolayer heterogeneity monitored by Brewster Angle Microscopy. The semiconductor properties depend on the peptide bond backbone orientation and tyrosine crosslinking. Our results indicate that one may design extended nano-sheets with particular electric properties, reminiscent of semiconductors. We propose to exploit such properties for biosensing and neural interfaces.
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Affiliation(s)
- Alain Bolaño Alvarez
- CIQUIBIC, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Argentina
| | - Marcelo Pino
- CIQUIBIC, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Argentina
| | - Steffen B Petersen
- Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark.
| | - Gerardo Daniel Fidelio
- CIQUIBIC, Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, CONICET, Universidad Nacional de Córdoba, Argentina.
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Mukhopadhyay S, Karuppannan SK, Guo C, Fereiro JA, Bergren A, Mukundan V, Qiu X, Castañeda Ocampo OE, Chen X, Chiechi RC, McCreery R, Pecht I, Sheves M, Pasula RR, Lim S, Nijhuis CA, Vilan A, Cahen D. Solid-State Protein Junctions: Cross- Laboratory Study Shows Preservation of Mechanism at Varying Electronic Coupling. iScience 2020; 23:101099. [PMID: 32438319 PMCID: PMC7235645 DOI: 10.1016/j.isci.2020.101099] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 03/01/2020] [Accepted: 04/20/2020] [Indexed: 12/14/2022] Open
Abstract
Successful integration of proteins in solid-state electronics requires contacting them in a non-invasive fashion, with a solid conducting surface for immobilization as one such contact. The contacts can affect and even dominate the measured electronic transport. Often substrates, substrate treatments, protein immobilization, and device geometries differ between laboratories. Thus the question arises how far results from different laboratories and platforms are comparable and how to distinguish genuine protein electronic transport properties from platform-induced ones. We report a systematic comparison of electronic transport measurements between different laboratories, using all commonly used large-area schemes to contact a set of three proteins of largely different types. Altogether we study eight different combinations of molecular junction configurations, designed so that Ageoof junctions varies from 105 to 10-3 μm2. Although for the same protein, measured with similar device geometry, results compare reasonably well, there are significant differences in current densities (an intensive variable) between different device geometries. Likely, these originate in the critical contact-protein coupling (∼contact resistance), in addition to the actual number of proteins involved, because the effective junction contact area depends on the nanometric roughness of the electrodes and at times, even the proteins may increase this roughness. On the positive side, our results show that understanding what controls the coupling can make the coupling a design knob. In terms of extensive variables, such as temperature, our comparison unanimously shows the transport to be independent of temperature for all studied configurations and proteins. Our study places coupling and lack of temperature activation as key aspects to be considered in both modeling and practice of protein electronic transport experiments.
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Affiliation(s)
- Sabyasachi Mukhopadhyay
- Weizmann Institute of Science, Rehovot 76100, Israel
- Department of Physics, SRM University – AP, Amaravati, Andhra Pradesh 522502, India
| | - Senthil Kumar Karuppannan
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Cunlan Guo
- Weizmann Institute of Science, Rehovot 76100, Israel
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
| | | | - Adam Bergren
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton AB T6G 2G2, Canada
| | - Vineetha Mukundan
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton AB T6G 2G2, Canada
| | - Xinkai Qiu
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Olga E. Castañeda Ocampo
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Xiaoping Chen
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Ryan C. Chiechi
- Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands
| | - Richard McCreery
- Department of Chemistry, University of Alberta, 11227 Saskatchewan Dr., Edmonton AB T6G 2G2, Canada
| | - Israel Pecht
- Weizmann Institute of Science, Rehovot 76100, Israel
| | | | - Rupali Reddy Pasula
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore
| | - Sierin Lim
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 70 Nanyang Drive, Singapore 637457, Singapore
| | - Christian A. Nijhuis
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
- Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore
| | - Ayelet Vilan
- Weizmann Institute of Science, Rehovot 76100, Israel
| | - David Cahen
- Weizmann Institute of Science, Rehovot 76100, Israel
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Kayser B, Fereiro JA, Bhattacharyya R, Cohen SR, Vilan A, Pecht I, Sheves M, Cahen D. Solid-State Electron Transport via the Protein Azurin is Temperature-Independent Down to 4 K. J Phys Chem Lett 2020; 11:144-151. [PMID: 31821001 DOI: 10.1021/acs.jpclett.9b03120] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Solid-state electronic transport (ETp) via the electron-transfer copper protein azurin (Az) was measured in Au/Az/Au junction configurations down to 4 K, the lowest temperature for solid-state protein-based junctions. Not only does lowering the temperature help when observing fine features of electronic transport, but it also limits possible electron transport mechanisms. Practically, wire-bonded devices-on-chip, carrying Az-based microscopic junctions, were measured in liquid He, minimizing temperature gradients across the samples. Much smaller junctions, in conducting-probe atomic force microscopy measurements, served, between room temperature and the protein's denaturation temperature (∼323 K), to check that conductance behavior is independent of device configuration or contact nature and thus is a property of the protein itself. Temperature-independent currents were observed from ∼320 to 4 K. The experimental results were fitted to a single-level Landauer model to extract effective energy barrier and electrode-molecule coupling strength values and to compare data sets. Our results strongly support that quantum tunneling, rather than hopping, dominates ETp via Az.
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Affiliation(s)
- Ben Kayser
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Jerry A Fereiro
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Rajarshi Bhattacharyya
- Braun Center for Submicron Research, Department of Condensed Matter Physics , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Sidney R Cohen
- Department of Chemical Research Support , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Ayelet Vilan
- Department of Chemical and Biological Physics , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Israel Pecht
- Department of Immunology , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - Mordechai Sheves
- Department of Organic Chemistry , Weizmann Institute of Science , Rehovot 76100 , Israel
| | - David Cahen
- Department of Materials and Interfaces , Weizmann Institute of Science , Rehovot 76100 , Israel
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Abstract
The measured electronic properties of proteins are known to depend critically on contacts, although little is known at the single-molecule level. Here, we have measured the conductance of single-protein molecules in their natural aqueous environment, but in conditions where no ion current flows, finding large conductances (nanosiemens) over long paths (many nanometers) when the protein is tethered by chemical contacts formed by binding-specific ligands. This provides a method for forming reliable contacts to proteins, and for the specific detection of single molecules. Thus, single antibodies, such as anti-Ebola IgG, can be detected electrically when they bind a peptide epitope tethered to electrodes, with no background signal from molecules that do not bind specifically. Proteins are widely regarded as insulators, despite reports of electrical conductivity. Here we use measurements of single proteins between electrodes, in their natural aqueous environment to show that the factor controlling measured conductance is the nature of the electrical contact to the protein, and that specific ligands make highly selective electrical contacts. Using six proteins that lack known electrochemical activity, and measuring in a potential region where no ion current flows, we find characteristic peaks in the distributions of measured single-molecule conductances. These peaks depend on the contact chemistry, and hence, on the current path through the protein. In consequence, the measured conductance distribution is sensitive to changes in this path caused by ligand binding, as shown with streptavidin–biotin complexes. Measured conductances are on the order of nanosiemens over distances of many nanometers, orders of magnitude more than could be accounted for by electron tunneling. The current is dominated by contact resistance, so the conductance for a given path is independent of the distance between electrodes, as long as the contact points on the protein can span the gap between electrodes. While there is no currently known biological role for high electronic conductance, its dependence on specific contacts has important technological implications, because no current is observed at all without at least one strongly bonded contact, so direct electrical detection is a highly selective and label-free single-molecule detection method. We demonstrate single-molecule, highly specific, label- and background free-electronic detection of IgG antibodies to HIV and Ebola viruses.
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