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Faries KM, Hanson DK, Buhrmaster JC, Hippleheuser S, Tira GA, Wyllie RM, Kohout CE, Magdaong NCM, Holten D, Laible PD, Kirmaier C. Two pathways to understanding electron transfer in reaction centers from photosynthetic bacteria: A comparison of Rhodobacter sphaeroides and Rhodobacter capsulatus mutants. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2024; 1865:149047. [PMID: 38692451 DOI: 10.1016/j.bbabio.2024.149047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/03/2024]
Abstract
The rates, yields, mechanisms and directionality of electron transfer (ET) are explored in twelve pairs of Rhodobacter (R.) sphaeroides and R. capsulatus mutant RCs designed to defeat ET from the excited primary donor (P*) to the A-side cofactors and re-direct ET to the normally inactive mirror-image B-side cofactors. In general, the R. sphaeroides variants have larger P+HB- yields (up to ∼90%) than their R. capsulatus analogs (up to ∼60%), where HB is the B-side bacteriopheophytin. Substitution of Tyr for Phe at L-polypeptide position L181 near BB primarily increases the contribution of fast P* → P+BB- → P+HB- two-step ET, where BB is the "bridging" B-side bacteriochlorophyll. The second step (∼6-8 ps) is slower than the first (∼3-4 ps), unlike A-side two-step ET (P* → P+BA- → P+HA-) where the second step (∼1 ps) is faster than the first (∼3-4 ps) in the native RC. Substitutions near HB, at L185 (Leu, Trp or Arg) and at M-polypeptide site M133/131 (Thr, Val or Glu), strongly affect the contribution of slower (20-50 ps) P* → P+HB- one-step superexchange ET. Both ET mechanisms are effective in directing electrons "the wrong way" to HB and both compete with internal conversion of P* to the ground state (∼200 ps) and ET to the A-side cofactors. Collectively, the work demonstrates cooperative amino-acid control of rates, yields and mechanisms of ET in bacterial RCs and how A- vs. B-side charge separation can be tuned in both species.
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Affiliation(s)
- Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Stephen Hippleheuser
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Ryan M Wyllie
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Nikki Cecil M Magdaong
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, IL 60439, United States of America
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, MO 63130, United States of America.
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2
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Guo C, Gavrilov Y, Gupta S, Bendikov T, Levy Y, Vilan A, Pecht I, Sheves M, Cahen D. Electron transport via tyrosine-doped oligo-alanine peptide junctions: role of charges and hydrogen bonding. Phys Chem Chem Phys 2022; 24:28878-28885. [PMID: 36441625 DOI: 10.1039/d2cp02807g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A way of modulating the solid-state electron transport (ETp) properties of oligopeptide junctions is presented by charges and internal hydrogen bonding, which affect this process markedly. The ETp properties of a series of tyrosine (Tyr)-containing hexa-alanine peptides, self-assembled in monolayers and sandwiched between gold electrodes, are investigated in response to their protonation state. Inserting a Tyr residue into these peptides enhances the ETp carried via their junctions. Deprotonation of the Tyr-containing peptides causes a further increase of ETp efficiency that depends on this residue's position. Combined results of molecular dynamics simulations and spectroscopic experiments suggest that the increased conductance upon deprotonation is mainly a result of enhanced coupling between the charged C-terminus carboxylate group and the adjacent Au electrode. Moreover, intra-peptide hydrogen bonding of the Tyr hydroxyl to the C-terminus carboxylate reduces this coupling. Hence, the extent of such a conductance change depends on the Tyr-carboxylate distance in the peptide's sequence.
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Affiliation(s)
- Cunlan Guo
- Departments of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 761001, Israel. .,College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China
| | - Yulian Gavrilov
- Departments of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 761001, Israel.,Division of Biophysical Chemistry, Center for Molecular Protein Science, Department of Chemistry, Lund University, SE-22100 Lund, Sweden
| | - Satyajit Gupta
- Departments of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 761001, Israel. .,Department of Chemistry, Indian Institute of Technology, Bhilai, 492015, India
| | - Tatyana Bendikov
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, 761001, Israel
| | - Yaakov Levy
- Departments of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 761001, Israel
| | - Ayelet Vilan
- Departments of Chemical & Biological Physics, Weizmann Institute of Science, Rehovot, 761001, Israel
| | - Israel Pecht
- Department of immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot, 761001, Israel
| | - Mordechai Sheves
- Departments of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 761001, Israel.
| | - David Cahen
- Departments of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot, 761001, Israel.
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3
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Magdaong NCM, Faries KM, Buhrmaster JC, Tira GA, Wyllie RM, Kohout CE, Hanson DK, Laible PD, Holten D, Kirmaier C. High Yield of B-Side Electron Transfer at 77 K in the Photosynthetic Reaction Center Protein from Rhodobacter sphaeroides. J Phys Chem B 2022; 126:8940-8956. [PMID: 36315401 DOI: 10.1021/acs.jpcb.2c05905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The primary electron transfer (ET) processes at 295 and 77 K are compared for the Rhodobacter sphaeroides reaction center (RC) pigment-protein complex from 13 mutants including a wild-type control. The engineered RCs bear mutations in the L and M polypeptides that largely inhibit ET from the excited state P* of the primary electron donor (P, a bacteriochlorophyll dimer) to the normally photoactive A-side cofactors and enhance ET to the C2-symmetry related, and normally photoinactive, B-side cofactors. P* decay is multiexponential at both temperatures and modeled as arising from subpopulations that differ in contributions of two-step ET (e.g., P* → P+BB- → P+HB-), one-step superexchange ET (e.g., P* → P+HB-), and P* → ground state. [HB and BB are monomeric bacteriopheophytin and bacteriochlorophyll, respectively.] The relative abundances of the subpopulations and the inherent rate constants of the P* decay routes vary with temperature. Regardless, ET to produce P+HB- is generally faster at 77 K than at 295 K by about a factor of 2. A key finding is that the yield of P+HB-, which ranges from ∼5% to ∼90% among the mutant RCs, is essentially the same at 77 K as at 295 K in each case. Overall, the results show that ET from P* to the B-side cofactors in these mutants does not require thermal activation and involves combinations of ET mechanisms analogous to those operative on the A side in the native RC.
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Affiliation(s)
- Nikki Cecil M Magdaong
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Kaitlyn M Faries
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - James C Buhrmaster
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Gregory A Tira
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Ryan M Wyllie
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Claire E Kohout
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Deborah K Hanson
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Philip D Laible
- Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Dewey Holten
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
| | - Christine Kirmaier
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, United States
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4
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Wang J, Huang JJ, Zhou Y, Liao Y, Li S, Zhang B, Feng S. Synchronous N and P Removal in Carbon-Coated Nanoscale Zerovalent Iron Autotrophic Denitrification─The Synergy of the Carbon Shell and P Removal. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:13314-13326. [PMID: 36041071 DOI: 10.1021/acs.est.2c02376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Fe0 is a promising electron donor for autotrophic denitrification in the simultaneous removal of nitrate and phosphorus in low C/N wastewater. However, P removal may inevitably inhibit bio-denitrification. It has not been well recognized and led to an overdose of iron materials. This study employed carbon-coated zerovalent iron (Fe0@C) to support autotrophic denitrification to mitigate the inhibition effects of P removal and enhance both N and P removal. The critical role of the carbon shell in Fe0@C was to block the direct contact between Fe0 and P and NO3--N, to maintain the Fe0 activity. Besides, P inhibited the chemical reduction of NO3--N by competing for Fe0 active sites. This indirectly boosted H2 generation and promoted bio-denitrification. P removal displayed negligible effects on microbial species but indirectly enhanced the nitrogen metabolic activities because of promoted H2 in Fe0@C-based autotrophic denitrification. Bio-denitrification, in turn, strengthened Fe-P co-precipitation by promoting the formation of ferric hydroxide as a secondary adsorbent for P removal. This study demonstrated an efficient method for simultaneous N and P removal in autotrophic denitrification and revealed the synergistic interactions among N and P removal processes.
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Affiliation(s)
- Jingshu Wang
- Sino-Canadian Joint R&D Center on Water and Environmental Safety/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, P.R. China
| | - Jinhui Jeanne Huang
- Sino-Canadian Joint R&D Center on Water and Environmental Safety/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, P.R. China
| | - Yan Zhou
- Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore 637141, Singapore
- School of Civil and Environmental Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Yuan Liao
- Sino-Canadian Joint R&D Center on Water and Environmental Safety/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, P.R. China
| | - Song Li
- Sino-Canadian Joint R&D Center on Water and Environmental Safety/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, P.R. China
| | - Beichen Zhang
- Sino-Canadian Joint R&D Center on Water and Environmental Safety/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, P.R. China
| | - Shiteng Feng
- Sino-Canadian Joint R&D Center on Water and Environmental Safety/College of Environmental Science and Engineering, Nankai University, No. 38 Tongyan Road, Jinnan District, Tianjin 300350, P.R. China
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5
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Abstract
Hole hopping through tryptophan/tyrosine chains enables rapid unidirectional charge transport over long distances. We have elucidated structural and dynamical factors controlling hopping speed and efficiency in two modified azurin constructs that include a rhenium(I) sensitizer, Re(His)(CO)3(dmp)+, and one or two tryptophans (W1, W2). Experimental kinetics investigations showed that the two closely spaced (3 to 4 Å) intervening tryptophans dramatically accelerated long-range electron transfer (ET) from CuI to the photoexcited sensitizer. In our theoretical work, we found that time-dependent density-functional theory (TDDFT) quantum mechanics/molecular mechanics/molecular dynamics (QM/MM/MD) trajectories of low-lying triplet excited states of ReI(His)(CO)3(dmp)+-W1(-W2) exhibited crossings between sensitizer-localized (*Re) and charge-separated [ReI(His)(CO)3(dmp•-)/(W1 •+ or W2 •+)] (CS1 or CS2) states. Our analysis revealed that the distances, angles, and mutual orientations of ET-active cofactors fluctuate in a relatively narrow range in which the cofactors are strongly coupled, enabling adiabatic ET. Water-dominated electrostatic field fluctuations bring *Re and CS1 states to a crossing where *Re(CO)3(dmp)+←W1 ET occurs, and CS1 becomes the lowest triplet state. ET is promoted by solvation dynamics around *Re(CO)3(dmp)+(W1); and CS1 is stabilized by Re(dmp•-)/W1 •+ electron/hole interaction and enhanced W1 •+ solvation. The second hop, W1 •+←W2, is facilitated by water fluctuations near the W1/W2 unit, taking place when the electrostatic potential at W2 drops well below that at W1 •+ Insufficient solvation and reorganization around W2 make W1 •+←W2 ET endergonic, shifting the equilibrium toward W1 •+ and decreasing the charge-separation yield. We suggest that multiscale TDDFT/MM/MD is a suitable technique to model the simultaneous evolution of photogenerated excited-state manifolds.
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Liu H, Ouyang F, Chen Z, Chen Z, Lichtfouse E. Weak electricity stimulates biological nitrate removal of wastewater: Hypothesis and first evidences. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:143764. [PMID: 33248788 DOI: 10.1016/j.scitotenv.2020.143764] [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: 09/01/2020] [Revised: 10/23/2020] [Accepted: 11/05/2020] [Indexed: 06/12/2023]
Abstract
Nitrate pollution in water is a worldwide health and environmental concern. Biological nitrate removal of wastewater is widely used countering eutrophication of water bodies; however it could be troublesome and expensive when influent carbon source is insufficient. Here we present a novel process, the microbial fuel cell (MFC)-resistance-type electrical stimulation denitrification process (RtESD) using microbial weak electricity originated from the wastewater, to enhance nitrate removal. Results show that the optimal nitrate dependent denitrification rate (0.027 mg N/L·h) and nitrate removal efficiency (98.1%) can be achieved; partial autotrophic denitrification was enhanced in RtESD under stimulation of 0.2 V of microbial weak electricity (MWE). Aromatic proteins also increased in the presence of 0.2 V MWE stimulation according to three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy profiles, indicating that electron transfer could be improved in the case of MWE stimulation. Furthermore, the microbial community structure and diversity analysis results demonstrated that MWE stimulation inhibited the heterotrophic denitrifying bacteria and activated the autotrophic denitrifying bacteria in RtESD. Two hypotheses, enhancement of electron transfer and improvement of microorganism activity, were proposed regarding to the MWE stimulated pathways. This study provided a promising method utilizing MWE derived from wastewater to improve the denitrification rate and removal efficiency of nitrate-containing wastewater treatment processes.
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Affiliation(s)
- Hongbo Liu
- School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Road, 200093, Shanghai, China.
| | - Feiyu Ouyang
- School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Road, 200093, Shanghai, China
| | - Zihua Chen
- School of Environment and Architecture, University of Shanghai for Science and Technology, 516 Jungong Road, 200093, Shanghai, China
| | - Zhongbing Chen
- Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 16500 Prague, Czech Republic
| | - Eric Lichtfouse
- Aix-Marseille Univ, CNRS, IRD, INRA, Coll France, CEREGE, 13100 Aix en Provence, France
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7
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Zhang L, Lu JR, Waigh TA. Electronics of peptide- and protein-based biomaterials. Adv Colloid Interface Sci 2021; 287:102319. [PMID: 33248339 DOI: 10.1016/j.cis.2020.102319] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/22/2022]
Abstract
Biologically inspired peptide- and protein-based materials are at the forefront of organic bioelectronics research due to their inherent conduction properties and excellent biocompatibility. Peptides have the advantages of structural simplicity and ease of synthesis providing credible prospects for mass production, whereas naturally expressed proteins offer inspiration with many examples of high performance evolutionary optimised bioelectronics properties. We review recent advances in the fundamental conduction mechanisms, experimental techniques and exemplar applications for the bioelectronics of self-assembling peptides and proteins. Diverse charge transfer processes, such as tunnelling, hopping and coupled transfer, are found in naturally occurring biological systems with peptides and proteins as the predominant building blocks to enable conduction in biology. Both theory and experiments allow detailed investigation of bioelectronic properties in order to design functionalized peptide- and protein-based biomaterials, e.g. to create biocompatible aqueous electrodes. We also highlight the design of bioelectronics devices based on peptides/proteins including field-effect transistors, piezoelectric energy harvesters and optoelectronics.
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Affiliation(s)
- L Zhang
- Biological Physics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - J R Lu
- Biological Physics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - T A Waigh
- Biological Physics, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK; Photon Science Institute, Department of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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8
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Song X, Fu Q, Bu Y. Nonlinear Migration Dynamics of Excess Electrons along Linear Oligopeptides Controlled by an Applied Electric Field. Chemphyschem 2019; 20:1497-1507. [PMID: 30912277 DOI: 10.1002/cphc.201900149] [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: 02/13/2019] [Revised: 03/16/2019] [Indexed: 11/06/2022]
Abstract
Migration of an excess electron along linear oligopeptides governed by the external electric field (Eex ) which is against the inner dipole electric field is theoretically investigated, including the effects of Eex on the structural and electronic properties of electron migration. Two structural properties including electron-binding ability and the dipole moment of linear oligopeptides are sensitive to the Eex values and can be largely modulated by Eex due to the competition of Eex and the inner electric field and electron transfer caused by Eex . In the case of low Eex values, two structural properties decrease slightly, while for high Eex values, the electron-binding ability continually increases strongly, with dipole moments firstly increasing significantly and then increasing more slowly at higher Eex . Additionally, linear oligopeptides of different chain lengths influence the modulation extent of Eex and the longer the chain length is, the more sensitive modulation of Eex is. In addition, electronic properties represented by electron spin densities and singly occupied molecular orbital distributions vary with Eex intensities, leading to an unusual electron migration behavior. As Eex increases, an excess electron transfers from the N-terminus to the C-terminus and jumps over a neighboring dipole unit of two termini to other units, respectively, instead of transferring by means of a one-by-one dipole unit hopping mechanism. These findings not only promote a deeper understanding of the connection between Eex and structural and electronic properties of electron transfer behavior in peptides, but also provide a new insight into the modulation of electron migration along the oligopeptides.
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Affiliation(s)
- Xiufang Song
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, People's Republic of China
| | - Qiang Fu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, People's Republic of China
| | - Yuxiang Bu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, People's Republic of China.,School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, 273165, People's Republic of China
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9
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Song X, Zhang F, Bu Y. Dynamic relaying properties of a β-turn peptide in long-range electron transfer. J Comput Chem 2019; 40:988-996. [PMID: 30451309 DOI: 10.1002/jcc.25541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 11/05/2022]
Abstract
The relay stations play a significant role in long-range charge hopping transfer in proteins. Although studies have clarified that many more protein structural motifs can function as relays in charge hopping transfers by acting as intermediate charge carriers, the relaying properties are still poorly understood. In this work, taking a β-turn oligopeptide as an example, we report a dynamic character of a relay with tunable relaying properties using the density functional theory calculations. Our main finding is that a β-turn peptide can serve as an effective electron relay in facilitating long-range electron migration and its relay properties is vibration-tunable. The vibration-induced structural transient distortions remarkably affect the lowest occupied molecular orbital (LUMO) energy, vertical electron affinity and electron-binding mode of the β-turn oligopeptide and the singly occupied molecular orbital (SOMO) energy of the corresponding electron adduct and thus the relaying properties. Different vibration modes lead to different structural distortions and thus have different effects on the relaying properties and ability of the β-turn peptide. For the relaying properties, there approximately is a linear negative correlation of electron affinity with the LUMO energy of the β-turn or the SOMO energy of its electron adduct. Besides, such relaying properties also vary in the vibration evolution process, and the electron-binding modes may be tunable. As an important addition to the known static charge relaying properties occurring in various protein structural motifs, this work reports the dynamic electron-relaying characteristics of a β-turn oligopeptide with variable relaying properties governed by molecular vibrations which can be applied to different proteins in mediating long-range charge transfers. Clearly, this work reveals molecular vibration effects on the electron relaying properties of protein structural motifs and provides new insights into the dynamics of long-range charge transfers in proteins. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Xiufang Song
- School of Chemistry &Chemical Engineering, Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China
| | - Fengying Zhang
- School of Chemistry &Chemical Engineering, Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China
| | - Yuxiang Bu
- School of Chemistry &Chemical Engineering, Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China
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10
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Na S, Jurkovic S, Friedrich T, Koslowski T. Charge transfer through a fragment of the respiratory complex I and its regulation: an atomistic simulation approach. Phys Chem Chem Phys 2018; 20:20023-20032. [PMID: 30022212 DOI: 10.1039/c8cp02420k] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We simulate electron transfer within a fragment of the NADH:ubiquinone oxidoreductase (respiratory complex I) of the hyperthermophilic bacterium Aquifex aeolicus. We apply molecular dynamics simulations, thermodynamic integration, and a thermodynamic network least squares analysis to compute two key parameters of Marcus' theory of charge transfer, the thermodynamic driving force and the reorganization energy. Intramolecular contributions to the Gibbs free energy differences of electron and hydrogen transfer processes, ΔG, are accessed by calibrating against experimental redox titration data. This approach permits the computation of the interactions between the species NAD+, FMNH2, N1a-, and N3-, and the construction of a free energy surface for the flow of electrons within the fragment. We find NAD+ to be a strong candidate for the regulation of charge transfer.
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Affiliation(s)
- Sehee Na
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße23a, 79104 Freiburg im Breisgau, Germany.
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11
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Insights into a hole transfer mechanism between glucose oxidase and a p-type organic semiconductor. Biosens Bioelectron 2018; 102:449-455. [DOI: 10.1016/j.bios.2017.11.053] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 11/16/2017] [Accepted: 11/17/2017] [Indexed: 01/03/2023]
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12
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Peptides as Bio-inspired Molecular Electronic Materials. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017. [PMID: 29081052 DOI: 10.1007/978-3-319-66095-0_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Understanding the electronic properties of single peptides is not only of fundamental importance to biology, but it is also pivotal to the realization of bio-inspired molecular electronic materials. Natural proteins have evolved to promote electron transfer in many crucial biological processes. However, their complex conformational nature inhibits a thorough investigation, so in order to study electron transfer in proteins, simple peptide models containing redox active moieties present as ideal candidates. Here we highlight the importance of secondary structure characteristic to proteins/peptides, and its relevance to electron transfer. The proposed mechanisms responsible for such transfer are discussed, as are details of the electrochemical techniques used to investigate their electronic properties. Several factors that have been shown to influence electron transfer in peptides are also considered. Finally, a comprehensive experimental and theoretical study demonstrates that the electron transfer kinetics of peptides can be successfully fine tuned through manipulation of chemical composition and backbone rigidity. The methods used to characterize the conformation of all peptides synthesized throughout the study are outlined, along with the various approaches used to further constrain the peptides into their geometric conformations. The aforementioned sheds light on the potential of peptides to one day play an important role in the fledgling field of molecular electronics.
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13
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Acharya A, Bogdanov AM, Grigorenko BL, Bravaya KB, Nemukhin AV, Lukyanov KA, Krylov AI. Photoinduced Chemistry in Fluorescent Proteins: Curse or Blessing? Chem Rev 2016; 117:758-795. [PMID: 27754659 DOI: 10.1021/acs.chemrev.6b00238] [Citation(s) in RCA: 174] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Photoinduced reactions play an important role in the photocycle of fluorescent proteins from the green fluorescent protein (GFP) family. Among such processes are photoisomerization, photooxidation/photoreduction, breaking and making of covalent bonds, and excited-state proton transfer (ESPT). Many of these transformations are initiated by electron transfer (ET). The quantum yields of these processes vary significantly, from nearly 1 for ESPT to 10-4-10-6 for ET. Importantly, even when quantum yields are relatively small, at the conditions of repeated illumination the overall effect is significant. Depending on the task at hand, fluorescent protein photochemistry is regarded either as an asset facilitating new applications or as a nuisance leading to the loss of optical output. The phenomena arising due to phototransformations include (i) large Stokes shifts, (ii) photoconversions, photoactivation, and photoswitching, (iii) phototoxicity, (iv) blinking, (v) permanent bleaching, and (vi) formation of long-lived intermediates. The focus of this review is on the most recent experimental and theoretical work on photoinduced transformations in fluorescent proteins. We also provide an overview of the photophysics of fluorescent proteins, highlighting the interplay between photochemistry and other channels (fluorescence, radiationless relaxation, and intersystem crossing). The similarities and differences with photochemical processes in other biological systems and in dyes are also discussed.
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Affiliation(s)
- Atanu Acharya
- Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States
| | - Alexey M Bogdanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia.,Nizhny Novgorod State Medical Academy , Nizhny Novgorod, Russia
| | - Bella L Grigorenko
- Department of Chemistry, Lomonosov Moscow State University , Moscow, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences , Moscow, Russia
| | - Ksenia B Bravaya
- Department of Chemistry, Boston University , Boston, Massachusetts United States
| | - Alexander V Nemukhin
- Department of Chemistry, Lomonosov Moscow State University , Moscow, Russia.,Emanuel Institute of Biochemical Physics, Russian Academy of Sciences , Moscow, Russia
| | - Konstantin A Lukyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Moscow, Russia.,Nizhny Novgorod State Medical Academy , Nizhny Novgorod, Russia
| | - Anna I Krylov
- Department of Chemistry, University of Southern California , Los Angeles, California 90089-0482, United States
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14
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Guo C, Yu X, Refaely-Abramson S, Sepunaru L, Bendikov T, Pecht I, Kronik L, Vilan A, Sheves M, Cahen D. Tuning electronic transport via hepta-alanine peptides junction by tryptophan doping. Proc Natl Acad Sci U S A 2016; 113:10785-90. [PMID: 27621456 PMCID: PMC5047155 DOI: 10.1073/pnas.1606779113] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Charge migration for electron transfer via the polypeptide matrix of proteins is a key process in biological energy conversion and signaling systems. It is sensitive to the sequence of amino acids composing the protein and, therefore, offers a tool for chemical control of charge transport across biomaterial-based devices. We designed a series of linear oligoalanine peptides with a single tryptophan substitution that acts as a "dopant," introducing an energy level closer to the electrodes' Fermi level than that of the alanine homopeptide. We investigated the solid-state electron transport (ETp) across a self-assembled monolayer of these peptides between gold contacts. The single tryptophan "doping" markedly increased the conductance of the peptide chain, especially when its location in the sequence is close to the electrodes. Combining inelastic tunneling spectroscopy, UV photoelectron spectroscopy, electronic structure calculations by advanced density-functional theory, and dc current-voltage analysis, the role of tryptophan in ETp is rationalized by charge tunneling across a heterogeneous energy barrier, via electronic states of alanine and tryptophan, and by relatively efficient direct coupling of tryptophan to a Au electrode. These results reveal a controlled way of modulating the electrical properties of molecular junctions by tailor-made "building block" peptides.
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Affiliation(s)
- Cunlan Guo
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100; Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Xi Yu
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Sivan Refaely-Abramson
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Lior Sepunaru
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100; Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Tatyana Bendikov
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Israel Pecht
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Leeor Kronik
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Ayelet Vilan
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100
| | - Mordechai Sheves
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel 76100
| | - David Cahen
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot, Israel 76100;
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15
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Bogdanov AM, Acharya A, Titelmayer AV, Mamontova AV, Bravaya KB, Kolomeisky AB, Lukyanov KA, Krylov AI. Turning On and Off Photoinduced Electron Transfer in Fluorescent Proteins by π-Stacking, Halide Binding, and Tyr145 Mutations. J Am Chem Soc 2016; 138:4807-17. [DOI: 10.1021/jacs.6b00092] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Alexey M. Bogdanov
- Shemiakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
- Nizhny Novgorod State Medical Academy, Nizhny Novgorod 603005, Russia
| | - Atanu Acharya
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
| | | | | | - Ksenia B. Bravaya
- Department
of Chemistry, Boston University, Boston, Massachusetts 02215, United States
| | | | - Konstantin A. Lukyanov
- Shemiakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
- Nizhny Novgorod State Medical Academy, Nizhny Novgorod 603005, Russia
| | - Anna I. Krylov
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089-0482, United States
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16
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Abstract
Oligoamides composed of anthranilic acid derivatives present a promising choice for mediating long-range charge transfer and controlling its directionality. Hole hopping, modulated by the anthranilamide (Aa) permanent dipoles, provides a plausible means for such rectified long-range charge transduction. All aliphatic and most aromatic amides, however, decompose upon oxidation, rendering them unacceptable for hole-hopping pathways. We, therefore, employ electrochemical and computational analysis to examine how to suppress oxidative degradation and stabilize the radical cations of N-acylated Aa derivatives. Our findings reveal two requirements for attaining long-lived radical cations of these aromatic amides: (1) keeping the reduction potentials for oxidizing the Aa residues under about 1.4 V vs SCE and (2) adding an electron-donating group para to the N-terminal amide of the aromatic ring, which prevents the electron spin density of the radical cation from extending over the C-terminal amide. These findings provide essential information for the design of hole-transfer amides.
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Affiliation(s)
- Eli M Espinoza
- Department of Chemistry, University of California , Riverside, California 92521, United States
| | - Jillian M Larsen
- Department of Bioengineering, University of California , Riverside, California 92521, United States
| | - Valentine I Vullev
- Department of Chemistry, University of California , Riverside, California 92521, United States
- Department of Bioengineering, University of California , Riverside, California 92521, United States
- Department of Biochemistry, University of California , Riverside, California 92521, United States
- Materials Science and Engineering Program, University of California , Riverside, California 92521, United States
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17
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Gnandt E, Dörner K, Strampraad MFJ, de Vries S, Friedrich T. The multitude of iron-sulfur clusters in respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1068-1072. [PMID: 26944855 DOI: 10.1016/j.bbabio.2016.02.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 02/19/2016] [Accepted: 02/26/2016] [Indexed: 12/13/2022]
Abstract
Respiratory complex I couples the electron transfer from NADH to ubiquinone with the translocation of protons across the membrane. Complex I contains one non-covalently bound flavin mononucleotide and, depending on the species, up to ten iron-sulfur (Fe/S) clusters as cofactors. The reason for the presence of the multitude of Fe/S clusters in complex I remained enigmatic for a long time. The question was partly answered by investigations on the evolution of the complex revealing the stepwise construction of the electron transfer domain from several modules. Extension of the ancestral to the modern electron input domain was associated with the acquisition of several Fe/S-proteins. The X-ray structure of the complex showed that the NADH oxidation-site is connected with the quinone-reduction site by a chain of seven Fe/S-clusters. Fast enzyme kinetics revealed that this chain of Fe/S-clusters is used to regulate electron-tunneling rates within the complex. A possible function of the off-pathway cluster N1a is discussed. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Emmanuel Gnandt
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, Albertstr. 21, 79104 Freiburg i. Br., Germany
| | - Katerina Dörner
- Deutsches Elektronen-Synchrotron DESY, CFEL, Notkestr. 85, Hamburg, Germany
| | - Marc F J Strampraad
- Delft University of Technology, Department of Biotechnology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Simon de Vries
- Delft University of Technology, Department of Biotechnology, Julianalaan 67, 2628 BC Delft, The Netherlands
| | - Thorsten Friedrich
- Albert-Ludwigs-Universität Freiburg, Institut für Biochemie, Albertstr. 21, 79104 Freiburg i. Br., Germany.
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18
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Feliciano GT, Steidl RJ, Reguera G. Structural and functional insights into the conductive pili of Geobacter sulfurreducens revealed in molecular dynamics simulations. Phys Chem Chem Phys 2015; 17:22217-26. [PMID: 26243427 DOI: 10.1039/c5cp03432a] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Geobacter sulfurreducens (GS) electronically connects with extracellular electron acceptors using conductive protein filaments or pili. To gain insights into their role as biological nanowires, we investigated the structural dynamics of the GS pilus in solution via molecular dynamics simulations. In the model, all of the pilin's aromatics clustered as a right-handed helical band along the pilus, maintaining inter-aromatic distances and dimer configurations optimal for multistep hopping. The aromatics were interspersed within the regions of highest negative potential, which influenced the type and configuration of the aromatic contacts and the rates of electron transfer. Small foci of positive potential were also present but were neutralized within uncharged regions, thus minimizing charge trapping. Consistent with the model predictions, mutant strains with reduced aromatic contacts or negative potentials had defects in pili functions such as the reduction of Fe(III) oxides and electrodes. The results therefore support the notion of a pilus fiber evolved to function as an electronic conduit between the cell and extracellular electron acceptors.
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Affiliation(s)
- G T Feliciano
- Departamento de Físico-Química, Instituto de Quimica, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Nanobionics Group, Sao Paulo, Araraquara, Brazil
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19
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Sun W, Shao M, Ren H, Xiao D, Qin X, Deng L, Chen X, Gao J. A New Type of Electron Relay Station in Proteins: Three-Piece S:Π∴S↔S∴Π:S Resonance Structure. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2015; 119:6998-7005. [PMID: 26113884 PMCID: PMC4476553 DOI: 10.1021/jp512628x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A type of relay station for electron transfer in proteins, three-piece five-electron bonding, is introduced in this paper, which is also first proposed here. The ab initio calculations predict the formation of S:Π∴S↔S∴Π:S resonance binding with an aromatic ring located in the middle of two sulfur-containing groups, which may participate in electron-hole transport in proteins. These special structures can lower the local ionization energies to capture electron holes efficiently and may be easily formed and broken because of their proper binding energies. In addition, the UV-vis spectra provide evidence of the formations of the three-piece five-electron binding. The cooperation of three adjacent pieces may be advantage to promote electron transfer a longer distance.
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Affiliation(s)
- Weichao Sun
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, People’s Republic of China
| | - Mengyao Shao
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, People’s Republic of China
| | - Haisheng Ren
- Department of Chemistry and Supercomputing Institute University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Dong Xiao
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, People’s Republic of China
| | - Xin Qin
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, People’s Republic of China
| | - Li Deng
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, People’s Republic of China
| | - Xiaohua Chen
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing, 400030, People’s Republic of China
- Department of Chemistry and Supercomputing Institute University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Jiali Gao
- Department of Chemistry and Supercomputing Institute University of Minnesota, Minneapolis, Minnesota 55455, United States
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20
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de Vries S, Dörner K, Strampraad MJF, Friedrich T. Die Elektronentunnelraten im Atmungskettenkomplex I sind auf eine effiziente Energiewandlung abgestimmt. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410967] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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de Vries S, Dörner K, Strampraad MJF, Friedrich T. Electron tunneling rates in respiratory complex I are tuned for efficient energy conversion. Angew Chem Int Ed Engl 2015; 54:2844-8. [PMID: 25600069 PMCID: PMC4506566 DOI: 10.1002/anie.201410967] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Indexed: 12/13/2022]
Abstract
Respiratory complex I converts the free energy of ubiquinone reduction by NADH into a proton motive force, a redox reaction catalyzed by flavin mononucleotide(FMN) and a chain of seven iron–sulfur centers. Electron transfer rates between the centers were determined by ultrafast freeze-quenching and analysis by EPR and UV/Vis spectroscopy. The complex rapidly oxidizes three NADH molecules. The electron-tunneling rate between the most distant centers in the middle of the chain depends on the redox state of center N2 at the end of the chain, and is sixfold slower when N2 is reduced. The conformational changes that accompany reduction of N2 decrease the electronic coupling of the longest electron-tunneling step. The chain of iron–sulfur centers is not just a simple electron-conducting wire; it regulates the electron-tunneling rate synchronizing it with conformation-mediated proton pumping, enabling efficient energy conversion. Synchronization of rates is a principle means of enhancing the specificity of enzymatic reactions.
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Affiliation(s)
- Simon de Vries
- Department of Biotechnology, Institution Delft University of Technology, Julianalaan 67, 2628 BC, Delft (The Netherlands).
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22
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Zhang R, Liu J, Yang H, Wang S, Zhang M, Bu Y. Computational insights into the charge relaying properties of β-turn peptides in protein charge transfers. Chemphyschem 2014; 16:436-46. [PMID: 25430869 DOI: 10.1002/cphc.201402657] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Indexed: 11/11/2022]
Abstract
Density functional theory calculations suggest that β-turn peptide segments can act as a novel dual-relay elements to facilitate long-range charge hopping transport in proteins, with the N terminus relaying electron hopping transfer and the C terminus relaying hole hopping migration. The electron- or hole-binding ability of such a β-turn is subject to the conformations of oligopeptides and lengths of its linking strands. On the one hand, strand extension at the C-terminal end of a β-turn considerably enhances the electron-binding of the β-turn N terminus, due to its unique electropositivity in the macro-dipole, but does not enhance hole-forming of the β-turn C terminus because of competition from other sites within the β-strand. On the other hand, strand extension at the N terminal end of the β-turn greatly enhances hole-binding of the β-turn C terminus, due to its distinct electronegativity in the macro-dipole, but does not considerably enhance electron-binding ability of the N terminus because of the shared responsibility of other sites in the β-strand. Thus, in the β-hairpin structures, electron- or hole-binding abilities of both termini of the β-turn motif degenerate compared with those of the two hook structures, due to the decreased macro-dipole polarity caused by the extending the two terminal strands. In general, the high polarity of a macro-dipole always plays a principal role in determining charge-relay properties through modifying the components and energies of the highest occupied and lowest unoccupied molecular orbitals of the β-turn motif, whereas local dipoles with low polarity only play a cooperative assisting role. Further exploration is needed to identify other factors that influence relay properties in these protein motifs.
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Affiliation(s)
- Ru Zhang
- Institute of Theoretical Chemistry, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100 (P.R. China)
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23
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Horsley JR, Yu J, Moore KE, Shapter JG, Abell AD. Unraveling the interplay of backbone rigidity and electron rich side-chains on electron transfer in peptides: the realization of tunable molecular wires. J Am Chem Soc 2014; 136:12479-88. [PMID: 25122122 PMCID: PMC4156867 DOI: 10.1021/ja507175b] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Indexed: 01/14/2023]
Abstract
Electrochemical studies are reported on a series of peptides constrained into either a 310-helix (1-6) or β-strand (7-9) conformation, with variable numbers of electron rich alkene containing side chains. Peptides (1 and 2) and (7 and 8) are further constrained into these geometries with a suitable side chain tether introduced by ring closing metathesis (RCM). Peptides 1, 4 and 5, each containing a single alkene side chain reveal a direct link between backbone rigidity and electron transfer, in isolation from any effects due to the electronic properties of the electron rich side-chains. Further studies on the linear peptides 3-6 confirm the ability of the alkene to facilitate electron transfer through the peptide. A comparison of the electrochemical data for the unsaturated tethered peptides (1 and 7) and saturated tethered peptides (2 and 8) reveals an interplay between backbone rigidity and effects arising from the electron rich alkene side-chains on electron transfer. Theoretical calculations on β-strand models analogous to 7, 8 and 9 provide further insights into the relative roles of backbone rigidity and electron rich side-chains on intramolecular electron transfer. Furthermore, electron population analysis confirms the role of the alkene as a "stepping stone" for electron transfer. These findings provide a new approach for fine-tuning the electronic properties of peptides by controlling backbone rigidity, and through the inclusion of electron rich side-chains. This allows for manipulation of energy barriers and hence conductance in peptides, a crucial step in the design and fabrication of molecular-based electronic devices.
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Affiliation(s)
- John R. Horsley
- ARC
Centre of Excellence for Nanoscale BioPhotonics (CNBP), School of
Chemistry and Physics, The University of
Adelaide, Adelaide, South Australia 5005, Australia
| | - Jingxian Yu
- ARC
Centre of Excellence for Nanoscale BioPhotonics (CNBP), School of
Chemistry and Physics, The University of
Adelaide, Adelaide, South Australia 5005, Australia
| | - Katherine E. Moore
- Centre
for Nanoscale Science and Technology, School of Chemical & Physical
Science, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Joe G. Shapter
- Centre
for Nanoscale Science and Technology, School of Chemical & Physical
Science, Flinders University, Bedford Park, South Australia 5042, Australia
| | - Andrew D. Abell
- ARC
Centre of Excellence for Nanoscale BioPhotonics (CNBP), School of
Chemistry and Physics, The University of
Adelaide, Adelaide, South Australia 5005, Australia
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24
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Friedrich T. On the mechanism of respiratory complex I. J Bioenerg Biomembr 2014; 46:255-68. [PMID: 25022766 DOI: 10.1007/s10863-014-9566-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 07/03/2014] [Indexed: 02/08/2023]
Abstract
The energy-converting NADH:ubiquinone oxidoreductase, respiratory complex I, couples the transfer of electrons from NADH to ubiquinone with the translocation of protons across the membrane. Electron microscopy and X-ray crystallography revealed the two-part structure of the enzyme complex. A peripheral arm extending into the aqueous phase catalyzes the electron transfer reaction. Accordingly, this arm contains the redox-active cofactors, namely one flavin mononucleotide (FMN) and up to ten iron-sulfur (Fe/S) clusters. A membrane arm embedded in the lipid bilayer catalyzes proton translocation by a yet unknown mechanism. The binding site of the substrate (ubi) quinone is located at the interface of the two arms. The oxidation of one NADH is coupled with the translocation of four protons across the membrane. In this review, the binding of the substrates, the intramolecular electron transfer, the role of individual Fe/S clusters and the mechanism of proton translocation are discussed in the light of recent data obtained from our laboratory.
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Affiliation(s)
- Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität, Albertstr. 21, 79104, Freiburg, Germany,
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25
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Barker CS, Meshcheryakova IV, Sasaki T, Roy MC, Sinha PK, Yagi T, Samatey FA. Randomly selected suppressor mutations in genes for NADH : quinone oxidoreductase-1, which rescue motility of a Salmonella ubiquinone-biosynthesis mutant strain. MICROBIOLOGY-SGM 2014; 160:1075-1086. [PMID: 24692644 DOI: 10.1099/mic.0.075945-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The primary mobile electron-carrier in the aerobic respiratory chain of Salmonella is ubiquinone. Demethylmenaquinone and menaquinone are alternative electron-carriers involved in anaerobic respiration. Ubiquinone biosynthesis was disrupted in strains bearing deletions of the ubiA or ubiE genes. In soft tryptone agar both mutant strains swam poorly. However, the ubiA deletion mutant strain produced suppressor mutant strains with somewhat rescued motility and growth. Six independent suppressor mutants were purified and comparative genome sequence analysis revealed that they each bore a single new missense mutation, which localized to genes for subunits of NADH : quinone oxidoreductase-1. Four mutants bore an identical nuoG(Q297K) mutation, one mutant bore a nuoM(A254S) mutation and one mutant bore a nuoN(A444E) mutation. The NuoG subunit is part of the hydrophilic domain of NADH : quinone oxidoreductase-1 and the NuoM and NuoN subunits are part of the hydrophobic membrane-embedded domain. Respiration was rescued and the suppressed mutant strains grew better in Luria-Bertani broth medium and could use l-malate as a sole carbon source. The quinone pool of the cytoplasmic membrane was characterized by reversed-phase HPLC. Wild-type cells made ubiquinone and menaquinone. Strains with a ubiA deletion mutation made demethylmenaquinone and menaquinone and the ubiE deletion mutant strain made demethylmenaquinone and 2-octaprenyl-6-methoxy-1,4-benzoquinone; the total quinone pool was reduced. Immunoblotting found increased NADH : quinone oxidoreductase-1 levels for ubiquinone-biosynthesis mutant strains and enzyme assays measured electron transfer from NADH to demethylmenaquinone or menaquinone. Under certain growth conditions the suppressor mutations improved electron flow activity of NADH : quinone oxidoreductase-1 for cells bearing a ubiA deletion mutation.
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Affiliation(s)
- Clive S Barker
- Trans-membrane Trafficking Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Irina V Meshcheryakova
- Trans-membrane Trafficking Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Toshio Sasaki
- Research Support Section, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Michael C Roy
- Research Support Section, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Prem Kumar Sinha
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Takao Yagi
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Fadel A Samatey
- Trans-membrane Trafficking Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
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26
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Ronca E, Pastore M, Belpassi L, De Angelis F, Angeli C, Cimiraglia R, Tarantelli F. Charge-displacement analysis for excited states. J Chem Phys 2014; 140:054110. [DOI: 10.1063/1.4863411] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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27
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Burggraf F, Koslowski T. Charge transfer through a cytochrome multiheme chain: Theory and simulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:186-92. [DOI: 10.1016/j.bbabio.2013.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/22/2013] [Accepted: 09/10/2013] [Indexed: 10/26/2022]
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28
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Zhou L, Bu Y. Excess electron capture by hydrated histidine side-chain group. COMPUT THEOR CHEM 2013. [DOI: 10.1016/j.comptc.2013.04.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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29
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Zhang M, Zhao J, Yang H, Liu P, Bu Y. 310-Helical Peptide Acting as a Dual Relay for Charge-Hopping Transfer in Proteins. J Phys Chem B 2013; 117:6385-93. [DOI: 10.1021/jp4012526] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Meng Zhang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China
| | - Jing Zhao
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China
| | - Hongfang Yang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China
| | - Ping Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China
| | - Yuxiang Bu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, PR China
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30
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Wallrapp FH, Voityuk AA, Guallar V. In-silico assessment of protein-protein electron transfer. a case study: cytochrome c peroxidase--cytochrome c. PLoS Comput Biol 2013; 9:e1002990. [PMID: 23555224 PMCID: PMC3605091 DOI: 10.1371/journal.pcbi.1002990] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/28/2013] [Indexed: 11/28/2022] Open
Abstract
The fast development of software and hardware is notably helping in closing the gap between macroscopic and microscopic data. Using a novel theoretical strategy combining molecular dynamics simulations, conformational clustering, ab-initio quantum mechanics and electronic coupling calculations, we show how computational methodologies are mature enough to provide accurate atomistic details into the mechanism of electron transfer (ET) processes in complex protein systems, known to be a significant challenge. We performed a quantitative study of the ET between Cytochrome c Peroxidase and its redox partner Cytochrome c. Our results confirm the ET mechanism as hole transfer (HT) through residues Ala194, Ala193, Gly192 and Trp191 of CcP. Furthermore, our findings indicate the fine evolution of the enzyme to approach an elevated turnover rate of 5.47×106 s−1 for the ET between Cytc and CcP through establishment of a localized bridge state in Trp191. We have developed a protocol capable of describing long-range electron transfer mechanisms at an atomic detailed level. We demonstrate the maturity of the computational techniques in obtaining a quantitative view of the Cytochrome c Peroxidase/Cytochrome c electron transfer process, known to be a significant challenge. In excellent agreement with experimental data, our results allow for the description of the electron transfer pathway, its mechanism and the electron transfer rate at a quantitative level. The overall protocol is free of parameterization and can be applied to any complex electron transfer process. Furthermore, the results reveal the fine enzyme evolution of this protein-protein complex to optimize its electron transfer rate by a localized bridge state.
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Affiliation(s)
- Frank H. Wallrapp
- Department of Life Sciences, Barcelona Supercomputing Center, Nexus II Building, Barcelona, Spain
| | - Alexander A. Voityuk
- Department of Computational Chemistry, University of Girona, Girona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Victor Guallar
- Department of Life Sciences, Barcelona Supercomputing Center, Nexus II Building, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
- * E-mail:
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31
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Zhang M, Zhao J, Liu J, Zhou L, Bu Y. Coexistence of solvated electron and benzene-centered valence anion in the negatively charged benzene-water clusters. J Chem Phys 2013; 138:014310. [PMID: 23298044 DOI: 10.1063/1.4773398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We present a combined M06 functional calculation and ab initio molecular dynamics simulation study of an excess electron (EE) in a microhydrated aromatic complex (modeled by benzene (Bz)-water binary clusters, Bz(H(2)O)(n)). Calculated results illustrate that Bz ring and water clusters are indeed linked through the π···HO interactions in the neutral Bz(H(2)O)(n) (n = 1-8) clusters, and the size of the water cluster does not influence the nature of its interaction with the π system for the oligo-hydrated complexes. The states and the dynamics of an EE trapped in such Bz-water clusters were also determined. All of possible localized states for the EE can be roughly classified into two types: (i) single, ring-localized states (the Bz-centered valence anions) in which an EE occupies the LUMO of the complexes originating from the LUMO (π*) of the Bz ring, and the π···HO interactions are enhanced for increase of electron density of the Bz ring. In this mode, the carbon skeleton of the Bz part is significantly deformed due to increase of electron density and nonsymmetric distribution of electron density induced by the interacting H-O bonds; (ii) solvated states, in which an EE is trapped directly as a surface state by the dangling hydrogen atoms of water molecules or as a solvated state in a mixed cavity formed by Bz and water cluster. In the latter case, Bz may also participate in capturing an EE using its C-H bonds in the side edge of the aromatic ring as a part of the cavity. In general, a small water cluster is favorable to the Bz-centered valence anion state, while a large one prefers a solvated electron state. Fluctuations and rearrangement of water molecules can sufficiently modify the relative energies of the EE states to permit facile conversion from the Bz-centered to the water cluster-centered state. This indicates that aromatic Bz can be identified as a stepping stone in electron transfer and the weak π···HO interaction plays an important role as the driving force in conversion of the two states.
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Affiliation(s)
- Meng Zhang
- The Center for Modeling and Simulation Chemistry, Institute of Theoretical Chemistry, Shandong University, Jinan 250100, People's Republic of China
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32
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Han B, Chen X, Zhao J, Bu Y. A peptide loop and an α-helix N-terminal serving as alternative electron hopping relays in proteins. Phys Chem Chem Phys 2012; 14:15849-59. [PMID: 23093308 DOI: 10.1039/c2cp41566f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
This work presents a density functional theory calculational study for clarifying that peptide loops (-[peptide](n)-) including the N-terminal and the C-terminal oligopeptides and the α-helix N-terminal can serve as an intriguing kind of relay elements, as an addition to the known relay stations served by aromatic amino acids for electron hopping migration. For these protein motifs, an excess electron generally prefers to reside at the -NH(3)(+) group in a Rydberg state for the N-terminal peptides, or at the -COOH group in a dipole-bound state for the C-terminal peptides, and at the N-terminal in a dipole-bound π*-orbital state for the peptide loops and α-helices. The electron binding ability can be effectively enhanced by elongation for the α-helix N-terminal, and by bending, twisting, and even β-turning for the peptide chains. The relay property is determined by the local dipole instead of the total dipole of the peptide chains. Although no direct experiment supports this hypothesis, a series of recent studies regarding charge hopping migration associated with the peptide chains and helices could be viewed as strong evidence. But, further studies are still needed by considering the effects from relative redox potential between the donor and acceptor sites, protein environment, and structure water molecules.
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Affiliation(s)
- Boran Han
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
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Sinha PK, Nakamaru-Ogiso E, Torres-Bacete J, Sato M, Castro-Guerrero N, Ohnishi T, Matsuno-Yagi A, Yagi T. Electron transfer in subunit NuoI (TYKY) of Escherichia coli NADH:quinone oxidoreductase (NDH-1). J Biol Chem 2012; 287:17363-17373. [PMID: 22474289 DOI: 10.1074/jbc.m111.329649] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bacterial proton-translocating NADH:quinone oxidoreductase (NDH-1) consists of a peripheral and a membrane domain. The peripheral domain catalyzes the electron transfer from NADH to quinone through a chain of seven iron-sulfur (Fe/S) clusters. Subunit NuoI in the peripheral domain contains two [4Fe-4S] clusters (N6a and N6b) and plays a role in bridging the electron transfer from cluster N5 to the terminal cluster N2. We constructed mutants for eight individual Cys-coordinating Fe/S clusters. With the exception of C63S, all mutants had damaged architecture of NDH-1, suggesting that Cys-coordinating Fe/S clusters help maintain the NDH-1 structure. Studies of three mutants (C63S-coordinating N6a, P110A located near N6a, and P71A in the vicinity of N6b) were carried out using EPR measurement. These three mutations did not affect the EPR signals from [2Fe-2S] clusters and retained electron transfer activities. Signals at g(z) = 2.09 disappeared in C63S and P110A but not in P71A. Considering our data together with the available information, g(z,x) = 2.09, 1.88 signals are assigned to cluster N6a. It is of interest that, in terms of g(z,x) values, cluster N6a is similar to cluster N4. In addition, we investigated the residues (Ile-94 and Ile-100) that are predicted to serve as electron wires between N6a and N6b and between N6b and N2, respectively. Replacement of Ile-100 and Ile-94 with Ala/Gly did not affect the electron transfer activity significantly. It is concluded that conserved Ile-100 and Ile-94 are not essential for the electron transfer.
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Affiliation(s)
- Prem Kumar Sinha
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Eiko Nakamaru-Ogiso
- Johnson Research Foundation, Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Jesus Torres-Bacete
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Motoaki Sato
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Norma Castro-Guerrero
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Tomoko Ohnishi
- Johnson Research Foundation, Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Akemi Matsuno-Yagi
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037
| | - Takao Yagi
- Department of Molecular and Experimental Medicine, MEM-256, The Scripps Research Institute, La Jolla, California 92037.
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Li W, Zhang Z, Yang H, Wu X, Liu J, Bu Y. Trapping of excess electrons at the microhydrated protonated amino groups in proteins. J Chem Phys 2012; 136:105101. [DOI: 10.1063/1.3685606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Koslowski T, Burggraf F, Krapf S, Steinbrecher T, Wittekindt C. Recent progress in biological charge transfer: theory and simulation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2012; 1817:1955-7. [PMID: 22395149 DOI: 10.1016/j.bbabio.2012.02.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 02/15/2012] [Accepted: 02/21/2012] [Indexed: 11/19/2022]
Abstract
In this contribution, we discuss three recent developments in atomistic biological charge transfer theory. First, in the context of Marcus' classical theory of charge transfer, key quantities of the theory such as driving forces and reorganization enthalpies are now accessible by thermodynamic integration schemes within standard molecular dynamics simulations at high accuracy. Second, direct simulations of charge transfer enable the computation of fast charge transfer reaction rates without having to resort to Marcus' theory. Finally, exploring the electronic structure beyond that of hitherto presumed centers of localization helps to identify new stepping stones of charge transfer reactions. This article is part of a Special Issue entitled: 17th European Bioenergetics Conference (EBEC 2012).
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Affiliation(s)
- Thorsten Koslowski
- Institut für Physikalische Chemie, Universität Freiburg, Freiburg im Breisgau, Germany.
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Bridges HR, Bill E, Hirst J. Mössbauer spectroscopy on respiratory complex I: the iron-sulfur cluster ensemble in the NADH-reduced enzyme is partially oxidized. Biochemistry 2011; 51:149-58. [PMID: 22122402 PMCID: PMC3254188 DOI: 10.1021/bi201644x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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In mitochondria, complex I (NADH:quinone oxidoreductase)
couples
electron transfer to proton translocation across an energy-transducing
membrane. It contains a flavin mononucleotide to oxidize NADH, and
an unusually long series of iron–sulfur (FeS) clusters that
transfer the electrons to quinone. Understanding electron transfer
in complex I requires spectroscopic and structural data to be combined
to reveal the properties of individual clusters and of the ensemble.
EPR studies on complex I from Bos taurus have established
that five clusters (positions 1, 2, 3, 5, and 7 along the seven-cluster
chain extending from the flavin) are (at least partially) reduced
by NADH. The other three clusters, positions 4 and 6 plus a cluster
on the other side of the flavin, are not observed in EPR spectra from
the NADH-reduced enzyme: they may remain oxidized, have unusual or
coupled spin states, or their EPR signals may be too fast relaxing.
Here, we use Mössbauer spectroscopy on 57Fe-labeled
complex I from the mitochondria of Yarrowia lipolytica to show that the cluster ensemble is only partially reduced in the
NADH-reduced enzyme. The three EPR-silent clusters are oxidized, and
only the terminal 4Fe cluster (position 7) is fully reduced. Together
with the EPR analyses, our results reveal an alternating profile of
higher and lower potential clusters between the two active sites in
complex I; they are not consistent with the consensus picture of a
set of isopotential clusters. The implications for intramolecular
electron transfer along the extended chain of cofactors in complex
I are discussed.
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Affiliation(s)
- Hannah R Bridges
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Cambridge, CB2 0XY, UK
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Biskup T, Hitomi K, Getzoff ED, Krapf S, Koslowski T, Schleicher E, Weber S. Identifikation unerwarteter Elektronentransferpfade im Cryptochrom durch zeitaufgelöste Elektronenspinresonanz-Spektroskopie. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Biskup T, Hitomi K, Getzoff ED, Krapf S, Koslowski T, Schleicher E, Weber S. Unexpected electron transfer in cryptochrome identified by time-resolved EPR spectroscopy. Angew Chem Int Ed Engl 2011; 50:12647-51. [PMID: 22086606 DOI: 10.1002/anie.201104321] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Indexed: 11/05/2022]
Abstract
Subtle differences in the local sequence and conformation of amino acids can result in diversity and specificity in electron transfer (ET) in proteins, despite structural conservation of the redox partners. For individual ET steps, distance is not necessarily the decisive parameter; orientation and solvent accessibility of the ET partners, and thus the stabilization of the charge-separated states, contribute substantially.
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Affiliation(s)
- Till Biskup
- Fachberich Physik, Freie Universität Berlin, Germany
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Purushotham U, Vijay D, Narahari Sastry G. A computational investigation and the conformational analysis of dimers, anions, cations, and zwitterions of L-phenylalanine. J Comput Chem 2011; 33:44-59. [DOI: 10.1002/jcc.21942] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 07/16/2011] [Indexed: 11/10/2022]
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40
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Burggraf F, Koslowski T. The simulation of interquinone charge transfer in a bacterial photoreaction center highlights the central role of a hydrogen-bonded non-heme iron complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2011; 1807:53-8. [DOI: 10.1016/j.bbabio.2010.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 08/02/2010] [Accepted: 08/05/2010] [Indexed: 11/30/2022]
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Abstract
NADH:ubiquinone oxidoreductase (complex I) plays a central role in the respiratory electron transport chain by coupling the transfer of electrons from NADH to ubiquinone to the creation of the proton gradient across the membrane necessary for ATP synthesis. Here the atomistic details of electronic wiring of all Fe/S clusters in complex I are revealed by using the tunneling current theory and computer simulations; both density functional theory and semiempirical electronic structure methods were used to examine antiferromagnetically coupled spin states and corresponding tunneling wave functions. Distinct electron tunneling pathways between neighboring Fe/S clusters are identified; the pathways primarily consist of two cysteine ligands and one additional key residue. Internal water between protein subunits is identified as an essential mediator enhancing the overall electron transfer rate by almost three orders of magnitude to achieve a physiologically significant value. The identified key residues are further characterized by sensitivity of electron transfer rates to their mutations, examined in simulations, and their conservation among complex I homologues. The unusual electronic structure properties of Fe(4)S(4) clusters in complex I explain their remarkable efficiency of electron transfer.
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Rothery RA, Bertero MG, Spreter T, Bouromand N, Strynadka NCJ, Weiner JH. Protein crystallography reveals a role for the FS0 cluster of Escherichia coli nitrate reductase A (NarGHI) in enzyme maturation. J Biol Chem 2010; 285:8801-7. [PMID: 20053990 DOI: 10.1074/jbc.m109.066027] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have used site-directed mutagenesis, EPR spectroscopy, redox potentiometry, and protein crystallography to monitor assembly of the FS0 [4Fe-4S] cluster and molybdo-bis(pyranopterin guanine dinucleotide) cofactor (Mo-bisPGD) of the Escherichia coli nitrate reductase A (NarGHI) catalytic subunit (NarG). Cys and Ser mutants of NarG-His(49) both lack catalytic activity, with only the former assembling FS0 and Mo-bisPGD. Importantly, both prosthetic groups are absent in the NarG-H49S mutant. EPR spectroscopy of the Cys mutant reveals that the E(m) value of the FS0 cluster is decreased by at least 500 mV, preventing its participation in electron transfer to the Mo-bisPGD cofactor. To demonstrate that decreasing the FS0 cluster E(m) results in decreased enzyme activity, we mutated a critical Arg residue (NarG-Arg(94)) in the vicinity of FS0 to a Ser residue. In this case, the E(m) of FS0 is decreased by 115 mV, with a concomitant decrease in enzyme turnover to approximately 30% of the wild type. Analysis of the structure of the NarG-H49S mutant reveals two important aspects of NarGHI maturation: (i) apomolybdo-NarGHI is able to bind GDP moieties at their respective P and Q sites in the absence of the Mo-bisPGD cofactor, and (ii) a critical segment of residues in NarG, (49)HGVNCTG(55), must be correctly positioned to ensure holoenzyme maturation.
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Affiliation(s)
- Richard A Rothery
- Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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Fleisher AJ, Morgan PJ, Pratt DW. Charge transfer by electronic excitation: Direct measurement by high resolution spectroscopy in the gas phase. J Chem Phys 2009; 131:211101. [DOI: 10.1063/1.3259690] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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45
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Wallrapp F, Voityuk A, Guallar V. Solvent Effects on Donor−Acceptor Couplings in Peptides. A Combined QM and MD Study. J Chem Theory Comput 2009; 5:3312-20. [DOI: 10.1021/ct900377j] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Frank Wallrapp
- Catalan Institució Catalana de Recerca i Estudis Avançats, 08010 barcelona, and Life Science Program, Barcelona Supercomputing Center, Nexus II Building, 08028 Barcelona, Spain, and Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, and Institut de Química Computational, Universitat de Girona, 17071 Girona, Spain; Catalan Institution for Research and Advanced Studies, Institute of Computational Chemistry, Department of Chemistry, University of Girona, 17071 Girona, Spain
| | - Alexander Voityuk
- Catalan Institució Catalana de Recerca i Estudis Avançats, 08010 barcelona, and Life Science Program, Barcelona Supercomputing Center, Nexus II Building, 08028 Barcelona, Spain, and Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, and Institut de Química Computational, Universitat de Girona, 17071 Girona, Spain; Catalan Institution for Research and Advanced Studies, Institute of Computational Chemistry, Department of Chemistry, University of Girona, 17071 Girona, Spain
| | - Victor Guallar
- Catalan Institució Catalana de Recerca i Estudis Avançats, 08010 barcelona, and Life Science Program, Barcelona Supercomputing Center, Nexus II Building, 08028 Barcelona, Spain, and Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, and Institut de Química Computational, Universitat de Girona, 17071 Girona, Spain; Catalan Institution for Research and Advanced Studies, Institute of Computational Chemistry, Department of Chemistry, University of Girona, 17071 Girona, Spain
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