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Andoralov V, Shleev S, Dergousova N, Kulikova O, Popov V, Tikhonova T. Octaheme nitrite reductase: The mechanism of intramolecular electron transfer and kinetics of nitrite bioelectroreduction. Bioelectrochemistry 2020; 138:107699. [PMID: 33221569 DOI: 10.1016/j.bioelechem.2020.107699] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/01/2020] [Accepted: 11/03/2020] [Indexed: 11/24/2022]
Abstract
Detailed impedance and voltammetric studies of hexameric octaheme nitrite reductase immobilized on carbon-based nanomaterials, specifically nanotubes and nanoparticles, were performed. Well-pronounced bioelectrocatalytic reduction of nitrite on enzyme-modified electrodes was obtained. Analysis of the impedance data indicated the absence of long-lived intermediates involved in the nitrite reduction. Cyclic voltammograms of biomodified electrodes had a bi-sigmoidal shape, which pointed to the presence of two enzyme orientations on carbon supports. The maximum (limiting) catalytic currents were determined and, by applying the correction by the mixed kinetics equation, the Tafel dependences were plotted for each catalytic wave/each enzyme orientation. Finally, two schemes for the rate-limiting processes during bioelectrocatalysis were proposed, viz. for low- and high-potential orientations.
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Affiliation(s)
- Victor Andoralov
- Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden
| | - Sergey Shleev
- Biomedical Sciences, Health & Society, Malmö University, 205 06 Malmö, Sweden; Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Natalia Dergousova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Olga Kulikova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia
| | - Vladimir Popov
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia; Kurchatov NBIC Centre, National Research Centre "Kurchatov Institute", 123182 Moscow, Russia
| | - Tamara Tikhonova
- Research Centre of Biotechnology, Russian Academy of Sciences, 119071 Moscow, Russia.
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Gnandt D, Na S, Koslowski T. Simulating biological charge transfer: Continuum dielectric theory or molecular dynamics? Biophys Chem 2018; 241:1-7. [PMID: 30036762 DOI: 10.1016/j.bpc.2018.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 07/01/2018] [Indexed: 10/28/2022]
Abstract
We study the thermodynamic parameters of Marcus's theory of charge transfer, the driving forces and the reorganization energies, using two widely applied approaches to bioenergetic problems that seem to be radically different: continuum dielectric theory via a numerical solution of Poisson's equation, and the thermodynamic integration approach based upon classical Newtonian molecular dynamics, as perfomed by Na et al., PCCP 19, 18,938 (2017). With application to a nitrite reductase NrfHA protein heterodimer, we obtain an excellent agreement between the respective driving forces with an r.m.s. deviation of 1.7 kcal/mol, and a lower limit to the reorganization energies. The computational methods turn out to be mutually supportive: molecular dynamics can be used to determine the parameters of a dielectric theory computation, which on the other hand can be used to properly rescale the reorganization energies and partition them into aqueous and protein contributions. In addition, we use the electrostatic approach to study the influence of Ca2+ ions on the free energy landscape of charge transfer.
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Affiliation(s)
- David Gnandt
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 23a, 79104 Freiburg im Breisgau, Germany
| | - Sehee Na
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 23a, 79104 Freiburg im Breisgau, Germany
| | - Thorsten Koslowski
- Institut für Physikalische Chemie, Universität Freiburg, Albertstraße 23a, 79104 Freiburg im Breisgau, Germany.
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Nilsson ZN, Mandella BL, Sen K, Kekilli D, Hough MA, Moenne-Loccoz P, Strange RW, Andrew CR. Distinguishing Nitro vs Nitrito Coordination in Cytochrome c' Using Vibrational Spectroscopy and Density Functional Theory. Inorg Chem 2017; 56:13205-13213. [PMID: 29053273 PMCID: PMC5677563 DOI: 10.1021/acs.inorgchem.7b01945] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nitrite coordination to heme cofactors is a key step in the anaerobic production of the signaling molecule nitric oxide (NO). An ambidentate ligand, nitrite has the potential to coordinate via the N- (nitro) or O- (nitrito) atoms in a manner that can direct its reactivity. Distinguishing nitro vs nitrito coordination, along with the influence of the surrounding protein, is therefore of particular interest. In this study, we probed Fe(III) heme-nitrite coordination in Alcaligenes xylosoxidans cytochrome c' (AXCP), an NO carrier that excludes anions in its native state but that readily binds nitrite (Kd ∼ 0.5 mM) following a distal Leu16 → Gly mutation to remove distal steric constraints. Room-temperature resonance Raman spectra (407 nm excitation) identify ν(Fe-NO2), δ(ONO), and νs(NO2) nitrite ligand vibrations in solution. Illumination with 351 nm UV light results in photoconversion to {FeNO}6 and {FeNO}7 states, enabling FTIR measurements to distinguish νs(NO2) and νas(NO2) vibrations from differential spectra. Density functional theory calculations highlight the connections between heme environment, nitrite coordination mode, and vibrational properties and confirm that nitrite binds to L16G AXCP exclusively through the N atom. Efforts to obtain the nitrite complex crystal structure were hampered by photochemistry in the X-ray beam. Although low dose crystal structures could be modeled with a mixed nitrite (nitro)/H2O distal population, their photosensitivity and partial occupancy underscores the value of the vibrational approach. Overall, this study sheds light on steric determinants of heme-nitrite binding and provides vibrational benchmarks for future studies of heme protein nitrite reactions.
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Affiliation(s)
- Zach N. Nilsson
- Department of Chemistry and Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Brian L. Mandella
- Department of Chemistry and Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Kakali Sen
- School of Biological Sciences, University of Essex, Colchester Essex, CO4 3SQ, United Kingdom
- Scientific Computing Department, STFC Daresbury Laboratory, Warrington, Cheshire WA4 4AD, United Kingdom
| | - Demet Kekilli
- School of Biological Sciences, University of Essex, Colchester Essex, CO4 3SQ, United Kingdom
| | - Michael A Hough
- School of Biological Sciences, University of Essex, Colchester Essex, CO4 3SQ, United Kingdom
| | - Pierre Moenne-Loccoz
- Division of Environmental and Biomolecular Systems, Oregon Health and Science University, Portland, Oregon 97239, United States
| | - Richard W. Strange
- School of Biological Sciences, University of Essex, Colchester Essex, CO4 3SQ, United Kingdom
| | - Colin R. Andrew
- Department of Chemistry and Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
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Weichenberger CX, Afonine PV, Kantardjieff K, Rupp B. The solvent component of macromolecular crystals. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1023-38. [PMID: 25945568 PMCID: PMC4427195 DOI: 10.1107/s1399004715006045] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 03/25/2015] [Indexed: 11/10/2022]
Abstract
The mother liquor from which a biomolecular crystal is grown will contain water, buffer molecules, native ligands and cofactors, crystallization precipitants and additives, various metal ions, and often small-molecule ligands or inhibitors. On average, about half the volume of a biomolecular crystal consists of this mother liquor, whose components form the disordered bulk solvent. Its scattering contributions can be exploited in initial phasing and must be included in crystal structure refinement as a bulk-solvent model. Concomitantly, distinct electron density originating from ordered solvent components must be correctly identified and represented as part of the atomic crystal structure model. Herein, are reviewed (i) probabilistic bulk-solvent content estimates, (ii) the use of bulk-solvent density modification in phase improvement, (iii) bulk-solvent models and refinement of bulk-solvent contributions and (iv) modelling and validation of ordered solvent constituents. A brief summary is provided of current tools for bulk-solvent analysis and refinement, as well as of modelling, refinement and analysis of ordered solvent components, including small-molecule ligands.
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Affiliation(s)
- Christian X. Weichenberger
- Center for Biomedicine, European Academy of Bozen/Bolzano (EURAC), Viale Druso 1, Bozen/Bolzano, I-39100 Südtirol/Alto Adige, Italy
| | - Pavel V. Afonine
- Physical Biosciences Division, Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Mail Stop 64R0121, Berkeley, CA 94720, USA
| | - Katherine Kantardjieff
- College of Science and Mathematics, California State University, San Marcos, CA 92078, USA
| | - Bernhard Rupp
- Department of Forensic Crystallography, k.-k. Hofkristallamt, 991 Audrey Place, Vista, CA 92084, USA
- Department of Genetic Epidemiology, Medical University of Innsbruck, Schöpfstrasse 41, A-6020 Innsbruck, Austria
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Trofimov AA, Polyakov KM, Lazarenko VA, Popov AN, Tikhonova TV, Tikhonov AV, Popov VO. Structural study of the X-ray-induced enzymatic reaction of octahaem cytochromecnitrite reductase. ACTA ACUST UNITED AC 2015; 71:1087-94. [DOI: 10.1107/s1399004715003053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Accepted: 02/12/2015] [Indexed: 11/10/2022]
Abstract
Octahaem cytochromecnitrite reductase from the bacteriumThioalkalivibrio nitratireducenscatalyzes the reduction of nitrite to ammonium and of sulfite to sulfide. The reducing properties of X-ray radiation and the high quality of the enzyme crystals allow study of the catalytic reaction of cytochromecnitrite reductase directly in a crystal of the enzyme, with the reaction being induced by X-rays. Series of diffraction data sets with increasing absorbed dose were collected from crystals of the free form of the enzyme and its complexes with nitrite and sulfite. The corresponding structures revealed gradual changes associated with the reduction of the catalytic haems by X-rays. In the case of the nitrite complex the conversion of the nitrite ions bound in the active sites to NO species was observed, which is the beginning of the catalytic reaction. For the free form, an increase in the distance between the oxygen ligand bound to the catalytic haem and the iron ion of the haem took place. In the case of the sulfite complex no enzymatic reaction was detected, but there were changes in the arrangement of the active-site water molecules that were presumably associated with a change in the protonation state of the sulfite ions.
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Tikhonova TV, Trofimov AA, Popov VO. Octaheme nitrite reductases: Structure and properties. BIOCHEMISTRY (MOSCOW) 2012; 77:1129-38. [DOI: 10.1134/s0006297912100057] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Tikhonova T, Tikhonov A, Trofimov A, Polyakov K, Boyko K, Cherkashin E, Rakitina T, Sorokin D, Popov V. Comparative structural and functional analysis of two octaheme nitrite reductases from closely relatedThioalkalivibriospecies. FEBS J 2012; 279:4052-61. [DOI: 10.1111/j.1742-4658.2012.08811.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tamara Tikhonova
- Bach Institute of Biochemistry; Russian Academy of Sciences, Leninskii pr. 33; Moscow 119071; Russia
| | - Alexey Tikhonov
- Bach Institute of Biochemistry; Russian Academy of Sciences, Leninskii pr. 33; Moscow 119071; Russia
| | | | | | | | - Eugene Cherkashin
- National Research Centre ‘Kurchatov Institute’, Academic Kurchatov sq. 1; Moscow 123182; Russia
| | - Tatiana Rakitina
- National Research Centre ‘Kurchatov Institute’, Academic Kurchatov sq. 1; Moscow 123182; Russia
| | - Dmitry Sorokin
- Winogradsky Institute of Microbiology; Russian Academy of Sciences, Leninskii pr. 32a; Moscow 119991; Russia
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Trofimov AA, Polyakov KM, Tikhonova TV, Tikhonov AV, Safonova TN, Boyko KM, Dorovatovskii PV, Popov VO. Covalent modifications of the catalytic tyrosine in octahaem cytochromecnitrite reductase and their effect on the enzyme activity. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2012; 68:144-53. [DOI: 10.1107/s0907444911052632] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 12/06/2011] [Indexed: 11/10/2022]
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