1
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Kobayashi K, Igarashi J, Kozawa T. Interdomain Electron Transfer in Flavohemoglobin from
Candida norvegensis
with Antibiotic Azole Compounds. FEBS Lett 2022; 596:938-946. [DOI: 10.1002/1873-3468.14327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 02/18/2022] [Accepted: 02/26/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Kazuo Kobayashi
- Institute of Scientific and Industrial Research Osaka University Mihogaoka 8‐1 Ibaraki Osaka 567‐0047 Japan
| | - Jotaro Igarashi
- Fukushima Medical University Hikaraigaoka 1 Fukushima 960‐1295 Japan
| | - Takahiro Kozawa
- Institute of Scientific and Industrial Research Osaka University Mihogaoka 8‐1 Ibaraki Osaka 567‐0047 Japan
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2
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Gardner PR. Ordered Motions in the Nitric-Oxide Dioxygenase Mechanism of Flavohemoglobin and Assorted Globins with Tightly Coupled Reductases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1414:45-96. [PMID: 36520413 DOI: 10.1007/5584_2022_751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nitric-oxide dioxygenases (NODs) activate and combine O2 with NO to form nitrate. A variety of oxygen-binding hemoglobins with associated partner reductases or electron donors function as enzymatic NODs. Kinetic and structural investigations of the archetypal two-domain microbial flavohemoglobin-NOD have illuminated an allosteric mechanism that employs selective tunnels for O2 and NO, gates for NO and nitrate, transient O2 association with ferric heme, and an O2 and NO-triggered, ferric heme spin crossover-driven, motion-controlled, and dipole-regulated electron-transfer switch. The proposed mechanism facilitates radical-radical coupling of ferric-superoxide with NO to form nitrate while preventing suicidal ferrous-NO formation. Diverse globins display the structural and functional motifs necessary for a similar allosteric NOD mechanism. In silico docking simulations reveal monomeric erythrocyte hemoglobin alpha-chain and beta-chain intrinsically matched and tightly coupled with NADH-cytochrome b5 oxidoreductase and NADPH-cytochrome P450 oxidoreductase, respectively, forming membrane-bound flavohemoglobin-like mammalian NODs. The neuroprotective neuroglobin manifests a potential NOD role in a close-fitting ternary complex with membrane-bound NADH-cytochrome b5 oxidoreductase and cytochrome b5. Cytoglobin interfaces weakly with cytochrome b5 for O2 and NO-regulated electron-transfer and coupled NOD activity. The mechanistic model also provides insight into the evolution of O2 binding cooperativity in hemoglobin and a basis for the discovery of allosteric NOD inhibitors.
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3
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Wu X, Hénin J, Baciou L, Baaden M, Cailliez F, de la Lande A. Mechanistic Insights on Heme-to-Heme Transmembrane Electron Transfer Within NADPH Oxydases From Atomistic Simulations. Front Chem 2021; 9:650651. [PMID: 34017816 PMCID: PMC8129163 DOI: 10.3389/fchem.2021.650651] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
NOX5 is a member of the NADPH oxidase family which is dedicated to the production of reactive oxygen species. The molecular mechanisms governing transmembrane electron transfer (ET) that permits to shuttle electrons over the biological membrane have remained elusive for a long time. Using computer simulations, we report conformational dynamics of NOX5 embedded within a realistic membrane environment. We assess the stability of the protein within the membrane and monitor the existence of cavities that could accommodate dioxygen molecules. We investigate the heme-to-heme electron transfer. We find a reaction free energy of a few tenths of eV (ca. −0.3 eV) and a reorganization free energy of around 1.1 eV (0.8 eV after including electrostatic induction corrections). The former indicates thermodynamically favorable ET, while the latter falls in the expected values for transmembrane inter-heme ET. We estimate the electronic coupling to fall in the range of the μeV. We identify electron tunneling pathways showing that not only the W378 residue is playing a central role, but also F348. Finally, we reveal the existence of two connected O2−binding pockets near the outer heme with fast exchange between the two sites on the nanosecond timescale. We show that when the terminal heme is reduced, O2 binds closer to it, affording a more efficient tunneling pathway than when the terminal heme is oxidized, thereby providing an efficient mechanism to catalyze superoxide production in the final step. Overall, our study reveals some key molecular mechanisms permitting reactive oxygen species production by NOX5 and paves the road for further investigation of ET processes in the wide family of NADPH oxidases by computer simulations.
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Affiliation(s)
- Xiaojing Wu
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rotschild, PSL Research University, Paris, France
| | - Jérôme Hénin
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rotschild, PSL Research University, Paris, France
| | - Laura Baciou
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), Orsay, France
| | - Marc Baaden
- CNRS, Université de Paris, UPR 9080, Laboratoire de Biochimie Théorique, Paris, France.,Institut de Biologie Physico-Chimique-Fondation Edmond de Rotschild, PSL Research University, Paris, France
| | - Fabien Cailliez
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), Orsay, France
| | - Aurélien de la Lande
- Institut de Chimie Physique, Université Paris Saclay, CNRS (UMR 8000), Orsay, France
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4
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Gardner AM, Gardner PR. Allostery in the nitric oxide dioxygenase mechanism of flavohemoglobin. J Biol Chem 2020; 296:100186. [PMID: 33310705 PMCID: PMC7948479 DOI: 10.1074/jbc.ra120.016637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
The substrates O2 and NO cooperatively activate the NO dioxygenase function of Escherichia coli flavohemoglobin. Steady-state and transient kinetic measurements support a structure-based mechanistic model in which O2 and NO movements and conserved amino acids at the E11, G8, E2, E7, B10, and F7 positions within the globin domain control activation. In the cooperative and allosteric mechanism, O2 migrates to the catalytic heme site via a long hydrophobic tunnel and displaces LeuE11 away from the ferric iron, which forces open a short tunnel to the catalytic site gated by the ValG8/IleE15 pair and LeuE11. NO permeates this tunnel and leverages upon the gating side chains triggering the CD loop to furl, which moves the E and F-helices and switches an electron transfer gate formed by LysF7, GlnE7, and water. This allows FADH2 to reduce the ferric iron, which forms the stable ferric–superoxide–TyrB10/GlnE7 complex. This complex reacts with internalized NO with a bimolecular rate constant of 1010 M−1 s−1 forming nitrate, which migrates to the CD loop and unfurls the spring-like structure. To restart the cycle, LeuE11 toggles back to the ferric iron. Actuating electron transfer with O2 and NO movements averts irreversible NO poisoning and reductive inactivation of the enzyme. Together, structure snapshots and kinetic constants provide glimpses of intermediate conformational states, time scales for motion, and associated energies.
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Affiliation(s)
- Anne M Gardner
- Research and Development Division, Miami Valley Biotech, Dayton, Ohio, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paul R Gardner
- Research and Development Division, Miami Valley Biotech, Dayton, Ohio, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; Chemistry and Biochemistry Department, University of Dayton, Dayton, Ohio, USA.
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5
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Abstract
Flavohaemoglobins were first described in yeast as early as the 1970s but their functions were unclear. The surge in interest in nitric oxide biology and both serendipitous and hypothesis-driven discoveries in bacterial systems have transformed our understanding of this unusual two-domain globin into a comprehensive, yet undoubtedly incomplete, appreciation of its pre-eminent role in nitric oxide detoxification. Here, I focus on research on the flavohaemoglobins of microorganisms, especially of bacteria, and update several earlier and more comprehensive reviews, emphasising advances over the past 5 to 10 years and some controversies that have arisen. Inevitably, in light of space restrictions, details of nitric oxide metabolism and globins in higher organisms are brief.
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Affiliation(s)
- Robert K. Poole
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Sheffield, S10 2TN, UK
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6
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Butcher D, Moussaoui M, Baciou L, Miksovska J. Impact of azole drugs on energetics, kinetics, and ligand migration pathways of CO photo-dissociation in bacterial flavohemoglobins. RSC Adv 2020; 10:17930-17941. [PMID: 35515592 PMCID: PMC9053618 DOI: 10.1039/d0ra02529a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 04/21/2020] [Indexed: 01/18/2023] Open
Abstract
Flavohemoglobins (fHbs) are heme proteins found in prokaryotic and eukaryotic microbes. They are involved in NO detoxification through an NO˙ dioxygenase mechanism. The N-terminal heme globin domain allows for binding of gaseous ligands whereas a C-terminal NADH/FADH binding domain facilitates association of redox cofactors necessary for ligand reduction. The NO˙ dioxygenase function is important in facilitating immune resistance by protecting the cell from nitrosative stress brought about by a host organism; as a result, bacterial flavoHbs have recently been considered as targets for the development of new antibiotics. Here, photoacoustic calorimetry and transient absorption spectroscopy have been used to characterize energetics, structural dynamics, and kinetics of CO migration within bacterial flavoHbs from Ralstonia eutropha (FHP) and Staphylococcus aureus (HMPSa) in the presence and absence of antibiotic azole compounds. In FHP, the ligand photo-release is associated with ΔH = 26.2 ± 7.0 kcal mol−1 and ΔV = 25.0 ± 1.5 mL mol−1 while in HMPSa, ΔH = 34.7 ± 8.0 kcal mol−1 and ΔV = 28.6 ± 17 mL mol−1 were observed, suggesting distinct structural changes associated with ligand escape from FHP and HMPSa. In the presence of ketoconazole, the CO escape leads to a more negative enthalpy change and volume change whereas association of miconazole to FHP or HMPSa does not impact the reaction volume. These data are in agreement with the computational results that propose distinct binding sites for ketoconazole and miconazole on CO bound FHP. Miconazole or ketoconazole binding to either protein has only a negligible impact on the CO association rates, indicating that azole drugs do not impact flavoHbs interactions with gaseous ligands but may inhibit the NOD activity through preventing the electron transfer between FAD and heme cofactors. Impact of ketoconalzole and miconazole on structural dynamics of flavohemoglobin.![]()
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Affiliation(s)
- David Butcher
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
| | - Myriam Moussaoui
- Laboratoire de Chimie Physique
- UMR8000
- Université Paris Sud
- CNRS
- Université Paris Saclay
| | - Laura Baciou
- Laboratoire de Chimie Physique
- UMR8000
- Université Paris Sud
- CNRS
- Université Paris Saclay
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
- Biomolecular Sciences Institute
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7
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Moussaoui M, Misevičienė L, Anusevičius Ž, Marozienė A, Lederer F, Baciou L, Čėnas N. Quinones and nitroaromatic compounds as subversive substrates of Staphylococcus aureus flavohemoglobin. Free Radic Biol Med 2018; 123:107-115. [PMID: 29793040 DOI: 10.1016/j.freeradbiomed.2018.05.071] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/09/2018] [Accepted: 05/18/2018] [Indexed: 11/23/2022]
Abstract
In microorganisms, flavohemoglobins (FHbs) containing FAD and heme (Fe3+, metHb) convert NO. into nitrate at the expense of NADH and O2. FHbs contribute to bacterial resistance to nitrosative stress. Therefore, inhibition of FHbs functions may decrease the pathogen virulence. We report here a kinetic study of the reduction of quinones and nitroaromatic compounds by S. aureus FHb. We show that this enzyme rapidly reduces quinones and nitroaromatic compounds in a mixed single- and two-electron pathway. The reactivity of nitroaromatics increased upon an increase in their single-electron reduction potential (E17), whereas the reactivity of quinones poorly depended on their E17 with a strong preference for a 2-hydroxy-1,4-naphthoquinone structure. The reaction followed a 'ping-pong' mechanism. In general, the maximal reaction rates were found lower than the maximal presteady-state rate of FAD reduction by NADH and/or of oxyhemoglobin (HbFe2+O2) formation (~130 s-1, pH 7.0, 25 °C), indicating that the enzyme turnover is limited by the oxidative half-reaction. The turnover studies showed that quinones prefreqently accept electrons from reduced FAD, and not from HbFe2+O2. These results suggest that quinones and nitroaromatics act as 'subversive substrates' for FHb, and may enhance the cytotoxicity of NO. by formation of superoxide and by diverting the electron flux coming from reduced FAD. Because quinone reduction rate was increased by FHb inhibitors such as econazole, ketoconazole, and miconazole, their combined use may represent a novel chemotherapeutical approach.
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Affiliation(s)
- Myriam Moussaoui
- Laboratoire de Chimie Physique, Université Paris Sud, CNRS UMR 8000, 91405 Orsay Cedex France
| | - Lina Misevičienė
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Žilvinas Anusevičius
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Audronė Marozienė
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania
| | - Florence Lederer
- Laboratoire de Chimie Physique, Université Paris Sud, CNRS UMR 8000, 91405 Orsay Cedex France
| | - Laura Baciou
- Laboratoire de Chimie Physique, Université Paris Sud, CNRS UMR 8000, 91405 Orsay Cedex France
| | - Narimantas Čėnas
- Institute of Biochemistry of Vilnius University, Saulėtekio 7, LT-10257 Vilnius, Lithuania.
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8
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Wang H, Liu F, Dong T, Du L, Zhang D, Gao J. Charge-Transfer Knowledge Graph among Amino Acids Derived from High-Throughput Electronic Structure Calculations for Protein Database. ACS OMEGA 2018; 3:4094-4104. [PMID: 31458645 PMCID: PMC6641752 DOI: 10.1021/acsomega.8b00336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 03/30/2018] [Indexed: 05/25/2023]
Abstract
The charge-transfer coupling is an important component in tight-binding methods. Because of the highly complex chemical structure of biomolecules, the anisotropic feature of charge-transfer couplings in realistic proteins cannot be ignored. In this work, we have performed the first large-scale quantitative assessment of charge-transfer preference by calculating the charge-transfer couplings in all 20 × 20 possible amino acid side-chain combinations, which are extracted from available high-quality structures of thousands of protein complexes. The charge-transfer database quantitatively shows distinct features of charge-transfer couplings among millions of amino acid side-chain combinations. The overall distribution of charge-transfer couplings reveals that only one average or representative structure cannot be regarded as the typical charge-transfer preference in realistic proteins. This work provides us an alternative route to comprehensively understand the charge-transfer couplings for the overall distribution of realistic proteins in the foreseen big data scenario.
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Affiliation(s)
- Hongwei Wang
- Hubei
Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Fang Liu
- Hubei
Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Tiange Dong
- Hubei
Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Likai Du
- Hubei
Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, P. R. China
| | - Dongju Zhang
- Institute
of Theoretical Chemistry, Shandong University, Jinan 250100, P. R. China
| | - Jun Gao
- Hubei
Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan 430070, P. R. China
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9
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Wu X, Clavaguera C, Lagardère L, Piquemal JP, de la Lande A. AMOEBA Polarizable Force Field Parameters of the Heme Cofactor in Its Ferrous and Ferric Forms. J Chem Theory Comput 2018; 14:2705-2720. [PMID: 29630819 DOI: 10.1021/acs.jctc.7b01128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report the first parameters of the heme redox cofactors for the polarizable AMOEBA force field in both the ferric and ferrous forms. We consider two types of complexes, one with two histidine side chains as axial ligands and one with a histidine and a methionine side chain as ligands. We have derived permanent multipoles from second-order Møller-Plesset perturbation theory (MP2). The sets of parameters have been validated in a first step by comparison of AMOEBA interaction energies of heme and a collection of biologically relevant molecules with MP2 and Density Functional Theory (DFT) calculations. In a second validation step, we consider interaction energies with large aggregates comprising around 80 H2O molecules. These calculations are repeated for 30 structures extracted from semiempirical PM7 DM simulations. Very encouraging agreement is found between DFT and the AMOEBA force field, which results from an accurate treatment of electrostatic interactions. We finally report long (10 ns) MD simulations of cytochromes in two redox states with AMOEBA testing both the 2003 and 2014 AMOEBA water models. These simulations have been carried out with the TINKER-HP (High Performance) program. In conclusion, owing to their ubiquity in biology, we think the present work opens a wide array of applications of the polarizable AMOEBA force field on hemeproteins.
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Affiliation(s)
- Xiaojing Wu
- Laboratoire de Chimie Physique , Université Paris Sud - CNRS, Université Paris Saclay , 15 Avenue Jean Perrin , 91405 Orsay Cedex , France
| | - Carine Clavaguera
- Laboratoire de Chimie Physique , Université Paris Sud - CNRS, Université Paris Saclay , 15 Avenue Jean Perrin , 91405 Orsay Cedex , France
| | - Louis Lagardère
- Sorbonne Université, CNRS , Institut Parisien de Chimie Physique et Théorique (IP2CT) , 4 Place Jussieu , F-75005 , Paris , France.,Sorbonne Université , Institut des Sciences du Calcul et des Données (ISCD) , 4 place Jussieu , F-75005 , Paris , France
| | - Jean-Philip Piquemal
- Sorbonne Université, CNRS , Laboratoire de Chimie Théorique (LCT) , 4 Place Jussieu , F-75005 , Paris , France.,Department of Biomedical Engineering , The University of Texas at Austin , Austin , Texas 78712 , United States.,Institut Universitaire de France , 75005 , Paris , France
| | - Aurélien de la Lande
- Laboratoire de Chimie Physique , Université Paris Sud - CNRS, Université Paris Saclay , 15 Avenue Jean Perrin , 91405 Orsay Cedex , France
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10
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Suess CJ, Hirst JD, Besley NA. Quantum chemical calculations of tryptophan → heme electron and excitation energy transfer rates in myoglobin. J Comput Chem 2017; 38:1495-1502. [PMID: 28369976 PMCID: PMC5434924 DOI: 10.1002/jcc.24793] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/01/2017] [Accepted: 03/03/2017] [Indexed: 11/10/2022]
Abstract
The development of optical multidimensional spectroscopic techniques has opened up new possibilities for the study of biological processes. Recently, ultrafast two-dimensional ultraviolet spectroscopy experiments have determined the rates of tryptophan → heme electron transfer and excitation energy transfer for the two tryptophan residues in myoglobin (Consani et al., Science, 2013, 339, 1586). Here, we show that accurate prediction of these rates can be achieved using Marcus theory in conjunction with time-dependent density functional theory. Key intermediate residues between the donor and acceptor are identified, and in particular the residues Val68 and Ile75 play a critical role in calculations of the electron coupling matrix elements. Our calculations demonstrate how small changes in structure can have a large effect on the rates, and show that the different rates of electron transfer are dictated by the distance between the heme and tryptophan residues, while for excitation energy transfer the orientation of the tryptophan residues relative to the heme is important. © 2017 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Christian J. Suess
- School of ChemistryUniversity of Nottingham, University ParkNottinghamNG7 2RDUnited Kingdom
| | - Jonathan D. Hirst
- School of ChemistryUniversity of Nottingham, University ParkNottinghamNG7 2RDUnited Kingdom
| | - Nicholas A. Besley
- School of ChemistryUniversity of Nottingham, University ParkNottinghamNG7 2RDUnited Kingdom
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11
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Blumberger J. Recent Advances in the Theory and Molecular Simulation of Biological Electron Transfer Reactions. Chem Rev 2015; 115:11191-238. [DOI: 10.1021/acs.chemrev.5b00298] [Citation(s) in RCA: 238] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Jochen Blumberger
- Department of Physics and
Astronomy, University College London, Gower Street, London WC1E 6BT, U.K
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12
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de la Lande A, Gillet N, Chen S, Salahub DR. Progress and challenges in simulating and understanding electron transfer in proteins. Arch Biochem Biophys 2015; 582:28-41. [PMID: 26116376 DOI: 10.1016/j.abb.2015.06.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 06/15/2015] [Accepted: 06/22/2015] [Indexed: 11/19/2022]
Abstract
This Review presents an overview of the most common numerical simulation approaches for the investigation of electron transfer (ET) in proteins. We try to highlight the merits of the different approaches but also the current limitations and challenges. The article is organized into three sections. Section 2 deals with direct simulation algorithms of charge migration in proteins. Section 3 summarizes the methods for testing the applicability of the Marcus theory for ET in proteins and for evaluating key thermodynamic quantities entering the reaction rates (reorganization energies and driving force). Recent studies interrogating the validity of the theory due to the presence of non-ergodic effects or of non-linear responses are also described. Section 4 focuses on the tunneling aspects of electron transfer. How can the electronic coupling between charge transfer states be evaluated by quantum chemistry approaches and rationalized? What interesting physics regarding the impact of protein dynamics on tunneling can be addressed? We will illustrate the different sections with examples taken from the literature to show what types of system are currently manageable with current methodologies. We also take care to recall what has been learned on the biophysics of ET within proteins thanks to the advent of atomistic simulations.
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Affiliation(s)
- Aurélien de la Lande
- Laboratoire de Chimie Physique, UMR 8000, CNRS, Université Paris Sud. 15, av. Jean Perrin, 91405 Orsay, France.
| | - Natacha Gillet
- Laboratoire de Chimie Physique, UMR 8000, CNRS, Université Paris Sud. 15, av. Jean Perrin, 91405 Orsay, France
| | - Shufeng Chen
- Laboratoire de Chimie Physique, UMR 8000, CNRS, Université Paris Sud. 15, av. Jean Perrin, 91405 Orsay, France
| | - Dennis R Salahub
- Department of Chemistry, CMS - Centre for Molecular Simulation and IQST - Institute for Quantum Science and Technology, University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada.
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13
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Narth C, Gillet N, Cailliez F, Lévy B, de la Lande A. Electron transfer, decoherence, and protein dynamics: insights from atomistic simulations. Acc Chem Res 2015; 48:1090-7. [PMID: 25730126 DOI: 10.1021/ar5002796] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electron transfer in biological systems drives the processes of life. From cellular respiration to photosynthesis and enzymatic catalysis, electron transfers (ET) are chemical processes on which essential biological functions rely. Over the last 40 years, scientists have sought understanding of how these essential processes function in biology. One important breakthrough was the discovery that Marcus theory (MT) of electron transfer is applicable to biological systems. Chemists have experimentally collected both the reorganization energies (λ) and the driving forces (ΔG°), two parameters of Marcus theory, for a large variety of ET processes in proteins. At the same time, theoretical chemists have developed computational approaches that rely on molecular dynamics and quantum chemistry calculations to access numerical estimates of λ and ΔG°. Yet another crucial piece in determining the rate of an electron transfer is the electronic coupling between the initial and final electronic wave functions. This is an important prefactor in the nonadiabatic rate expression, since it reflects the probability that an electron tunnels from the electron donor to the acceptor through the intervening medium. The fact that a protein matrix supports electron tunneling much more efficiently than vacuum is now well documented, both experimentally and theoretically. Meanwhile, many chemists have provided examples of the rich physical chemistry that can be induced by protein dynamics. This Account describes our studies of the dynamical effects on electron tunneling. We present our analysis of two examples of natural biological systems through MD simulations and tunneling pathway analyses. Through these examples, we show that protein dynamics sustain efficient tunneling. Second, we introduce two time scales: τcoh and τFC. The former characterizes how fast the electronic coupling varies with nuclear vibrations (which cause dephasing). The latter reflects the time taken by the system to leave the crossing region. In the framework of open quantum systems, τFC is a short time approximation of the characteristic decoherence time of the electronic subsystem in interaction with its nuclear environment. The comparison of the respective values of τcoh and τFC allows us to probe the occurrence of non-Condon effects. We use ab initio MD simulations to analyze how decoherence appears in several biological cofactors. We conclude that we cannot account for its order of magnitude by considering only the atoms or bonds directly concerned with the transfer. Decoherence results from contributions from all atoms of the system appearing with a time delay that increases with the distance from the primarily concerned atoms or bonds. The delay and magnitude of the contributions depend on the chemical nature of the system. Finally, we present recent developments based on constrained DFT for efficient and accurate evaluations of the electronic coupling in ab initio MD simulations. These are promising methods to study the subtle fluctuations of the electronic coupling and the mechanisms of electronic decoherence in biological systems.
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Affiliation(s)
- Christophe Narth
- Laboratoire
de Chimie Théorique, CNRS UMR 7616, Université Pierre et Marie Curie, case courrier 137. 4, Place Jussieu, 75252 Cedex 05 Paris, France
| | - Natacha Gillet
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
| | - Fabien Cailliez
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
| | - Bernard Lévy
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
| | - Aurélien de la Lande
- Laboratoire
de Chimie-Physique, CNRS UMR 8000, Université Paris Sud, Bâtiment
349 - Campus d’Orsay. 15, avenue Jean Perrin, 91405 Cedex Orsay, France
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Cailliez F, Müller P, Gallois M, de la Lande A. ATP binding and aspartate protonation enhance photoinduced electron transfer in plant cryptochrome. J Am Chem Soc 2014; 136:12974-86. [PMID: 25157750 DOI: 10.1021/ja506084f] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cryptochromes are flavoproteins encountered in most vegetal and animal species. They play a role of blue-light receptors in plants and in invertebrates. The putative resting state of the FAD cofactor in these proteins is its fully oxidized form, FADox. Upon blue-light excitation, the isoalloxazine ring (ISO) may undergo an ultrafast reduction by a nearby tryptophan residue W400. This primary reduction triggers a cascade of electron and proton transfers, ultimately leading to the formation of the FADH° radical. A recent experimental study has shown that the yield of FADH° formation in Arabidopsis cryptochrome can be strongly modulated by ATP binding and by pH, affecting the protonation state of D396 (proton donor to FAD°(-)). Here we provide a detailed molecular analysis of these effects by means of combined classical molecular dynamics simulations and time-dependent density functional theory calculations. When ATP is present and D396 protonated, FAD remains in close contact with W400, thereby enhancing electron transfer (ET) from W400 to ISO*. In contrast, deprotonation of D396 and absence of ATP introduce flexibility to the photoactive site prior to FAD excitation, with the consequence of increased ISO-W400 distance and diminished tunneling rate by almost two orders of magnitude. We show that under these conditions, ET from the adenine moiety of FAD becomes a competitive relaxation pathway. Overall, our data suggest that the observed effects of ATP and pH on the FAD photoreduction find their roots in the earliest stage of the photoreduction process; i.e., ATP binding and the protonation state of D396 determine the preferred pathway of ISO* relaxation.
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Affiliation(s)
- Fabien Cailliez
- Laboratoire de Chimie Physique, UMR 8000, Université Paris-Sud and CNRS , Orsay F-91405, France
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15
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Antimicrobial Agents Act Differently on Staphyloccocus aureus and Ralstonia eutropha Flavohemoglobins. Appl Biochem Biotechnol 2014; 173:1023-37. [DOI: 10.1007/s12010-014-0938-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/21/2014] [Indexed: 11/25/2022]
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Heck A, Woiczikowski PB, Kubař T, Welke K, Niehaus T, Giese B, Skourtis S, Elstner M, Steinbrecher TB. Fragment Orbital Based Description of Charge Transfer in Peptides Including Backbone Orbitals. J Phys Chem B 2014; 118:4261-72. [DOI: 10.1021/jp408907g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Alexander Heck
- Department
for Theoretical Chemical Biology, Institute for Physical Chemistry, Kaiserstrasse 12, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - P. Benjamin Woiczikowski
- Department
for Theoretical Chemical Biology, Institute for Physical Chemistry, Kaiserstrasse 12, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Tomáš Kubař
- Department
for Theoretical Chemical Biology, Institute for Physical Chemistry, Kaiserstrasse 12, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Kai Welke
- Department
for Theoretical Chemical Biology, Institute for Physical Chemistry, Kaiserstrasse 12, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Thomas Niehaus
- Department
of Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Bernd Giese
- Department
of Chemistry, University of Fribourg, Chemin du Musee 9, CH-1700 Fribourg, Switzerland
| | - Spiros Skourtis
- Department
of Physics, University of Cyprus, PO Box 20537, Nicosia 1678, Cyprus
| | - Marcus Elstner
- Department
for Theoretical Chemical Biology, Institute for Physical Chemistry, Kaiserstrasse 12, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
| | - Thomas B. Steinbrecher
- Department
for Theoretical Chemical Biology, Institute for Physical Chemistry, Kaiserstrasse 12, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany
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17
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Abstract
Electron transfer between redox proteins participating in energy chains of biology is required to proceed with high energetic efficiency, minimizing losses of redox energy to heat. Within the standard models of electron transfer, this requirement, combined with the need for unidirectional (preferably activationless) transitions, is translated into the need to minimize the reorganization energy of electron transfer. This design program is, however, unrealistic for proteins whose active sites are typically positioned close to the polar and flexible protein-water interface to allow inter-protein electron tunneling. The high flexibility of the interfacial region makes both the hydration water and the surface protein layer act as highly polar solvents. The reorganization energy, as measured by fluctuations, is not minimized, but rather maximized in this region. Natural systems in fact utilize the broad breadth of interfacial electrostatic fluctuations, but in the ways not anticipated by the standard models based on equilibrium thermodynamics. The combination of the broad spectrum of static fluctuations with their dispersive dynamics offers the mechanism of dynamical freezing (ergodicity breaking) of subsets of nuclear modes on the time of reaction/residence of the electron at a redox cofactor. The separation of time-scales of nuclear modes coupled to electron transfer allows dynamical freezing. In particular, the separation between the relaxation time of electro-elastic fluctuations of the interface and the time of conformational transitions of the protein caused by changing redox state results in dynamical freezing of the latter for sufficiently fast electron transfer. The observable consequence of this dynamical freezing is significantly different reorganization energies describing the curvature at the bottom of electron-transfer free energy surfaces (large) and the distance between their minima (Stokes shift, small). The ratio of the two reorganization energies establishes the parameter by which the energetic efficiency of protein electron transfer is increased relative to the standard expectations, thus minimizing losses of energy to heat. Energetically efficient electron transfer occurs in a chain of conformationally quenched cofactors and is characterized by flattened free energy surfaces, reminiscent of the flat and rugged landscape at the stability basin of a folded protein.
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Affiliation(s)
- Dmitry V Matyushov
- Center for Biological Physics, Arizona State University, PO Box 871504, Tempe, Arizona 85287-1504, USA.
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18
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Vinogradov SN, Bailly X, Smith DR, Tinajero-Trejo M, Poole RK, Hoogewijs D. Microbial eukaryote globins. Adv Microb Physiol 2013; 63:391-446. [PMID: 24054801 DOI: 10.1016/b978-0-12-407693-8.00009-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A bioinformatics survey of about 120 protist and 240 fungal genomes and transcriptomes revealed a broad array of globins, representing five of the eight subfamilies identified in bacteria. Most conspicuous is the absence of protoglobins and globin-coupled sensors, except for a two-domain globin in Leishmanias, that comprises a nucleotidyl cyclase domain, and the virtual absence of truncated group 3 globins. In contrast to bacteria, co-occurrence of more than two globin subfamilies appears to be rare in protists. Although globins were lacking in the Apicomplexa and the Microsporidia intracellular pathogens, they occurred in the pathogenic Trypanosomatidae, Stramenopiles and certain fungi. Flavohaemoglobins (FHbs) and related single-domain globins occur across the protist groups. Fungi are unique in having FHbs co-occurring with sensor single-domain globins (SSDgbs). Obligately biotrophic fungi covered in our analysis lack globins. Furthermore, SSDgbs occur only in a heterolobosean amoeba, Naegleria and the stramenopile Hyphochytrium. Of the three subfamilies of truncated Mb-fold globins, TrHb1s appear to be the most widespread, occurring as multiple copies in chlorophyte and ciliophora genomes, many as multidomain proteins. Although the ciliates appear to have only TrHb1s, the chlorophytes have Mb-like globins and TrHb2s, both closely related to the corresponding plant globins. The presently available number of protist genomes is inadequate to provide a definitive census of their globins. Bayesian molecular analyses of single-domain 3/3 Mb-fold globins suggest a close relationship of chlorophyte and haptophyte globins, including choanoflagellate and Capsaspora globins to land plant symbiotic and non-symbiotic haemoglobins and to vertebrate neuroglobins.
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19
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Gardner PR. Hemoglobin: a nitric-oxide dioxygenase. SCIENTIFICA 2012; 2012:683729. [PMID: 24278729 PMCID: PMC3820574 DOI: 10.6064/2012/683729] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/04/2012] [Indexed: 05/09/2023]
Abstract
Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs). Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.
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Affiliation(s)
- Paul R. Gardner
- Miami Valley Biotech, 1001 E. 2nd Street, Suite 2445, Dayton, OH 45402, USA
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