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Radoń M. Predicting spin states of iron porphyrins with DFT methods including crystal packing effects and thermodynamic corrections. Phys Chem Chem Phys 2024; 26:18182-18195. [PMID: 38899797 DOI: 10.1039/d4cp01327a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Accurate computational treatment of spin states for transition metal complexes, exemplified by iron porphyrins, lies at the heart of quantum bioinorganic chemistry, but at the same time represents a great challenge for approximate density functional theory (DFT) methods, which are predominantly used. Here, the accuracy of DFT methods for spin-state splittings in iron porphyrin is assessed by probing the ability to correctly predict the ground states for six FeIII or FeII complexes experimentally characterized in solid state. For each case, molecular and periodic DFT calculations are employed to quantify the effect of porphyrin side substituents and the crystal packing effect (CPE) on the spin-state splitting. It is proposed to partition the total CPE into additive components, the direct and structural one, the importance of which is shown to significantly vary from case to case. By knowing the substituent effect, the CPE, and the Gibbs free energy thermodynamic correction from calculations, one can employ the experimental ground-state information in order to derive a quantitative constraint on the electronic energy difference for a simplified (porphin) model of the experimentally characterized metalloporphyrin. The constraints derived in such a way-in the form of single or double inequalities-are used to assess the accuracy of dispersion-corrected DFT methods for 6 spin-state splittings of [FeIII(P)(2-MeIm)2]+, [FeIII(P)(2-MeIm)]+, [FeII(P)(THF)2] and [FeII(P)] models (where P is porphin, 2-MeIm is 2-methylimidazole, THF is tetrahydrofuran). These data constitute the new benchmark set of spin states for crystalline iron porphyrins (SSCIP6). The highest accuracy is obtained in the case of double-hybrid functionals (B2PLYP-D3, DSD-PBEB95-D3), whereas hybrid functionals, especially those with reduced admixture of the exact exchange (B3LYP*-D3, TPSSh-D3), are found to considerably overstabilize the intermediate spin state, leading to incorrect ground-state prediction in FeIII porphyrins. The present approach, which can be generalized to other transition metal complexes, is not only useful in method benchmarking, but also sheds light on the interpretations of experimental data for metalloporphyrins, which are important models to understand the electronic properties of heme proteins.
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Affiliation(s)
- Mariusz Radoń
- Faculty of Chemistry, Jagiellonian University, Kraków, Poland.
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2
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De Simone G, di Masi A, Sbardella D, Ascenzi P, Coletta M. Nitric Oxide Binding Geometry in Heme-Proteins: Relevance for Signal Transduction. Antioxidants (Basel) 2024; 13:666. [PMID: 38929104 PMCID: PMC11201058 DOI: 10.3390/antiox13060666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/28/2024] Open
Abstract
Nitric oxide (NO) synthesis, signaling, and scavenging is associated to relevant physiological and pathological events. In all tissues and organs, NO levels and related functions are regulated at different levels, with heme proteins playing pivotal roles. Here, we focus on the structural changes related to the different binding modes of NO to heme-Fe(II), as well as the modulatory effects of this diatomic messenger on heme-protein functions. Specifically, the ability of heme proteins to bind NO at either the distal or proximal side of the heme and the transient interchanging of the binding site is reported. This sheds light on the regulation of O2 supply to tissues with high metabolic activity, such as the retina, where a precise regulation of blood flow is necessary to meet the demand of nutrients.
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Affiliation(s)
- Giovanna De Simone
- Dipartimento di Scienze, Università degli Studi Roma Tre, 00146 Rome, Italy; (G.D.S.); (A.d.M.)
| | - Alessandra di Masi
- Dipartimento di Scienze, Università degli Studi Roma Tre, 00146 Rome, Italy; (G.D.S.); (A.d.M.)
- Centro Linceo Interdisciplinare “Beniamino Segre”, Accademia dei Lincei, 00165 Rome, Italy
| | | | - Paolo Ascenzi
- Dipartimento di Scienze, Università degli Studi Roma Tre, 00146 Rome, Italy; (G.D.S.); (A.d.M.)
- Accademia Nazionale dei Lincei, 00165 Rome, Italy
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3
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Sarkar S, Tiwari RK, Samanta D, Guchhait T, Sañudo EC, Rajaraman G, Rath SP. Unusual Stabilisation of Remarkably Bent Tetra-Cationic Tetra-radical Intermolecular Fe(III) μ-Oxo Tetranuclear Complexes. Angew Chem Int Ed Engl 2024; 63:e202402344. [PMID: 38478415 DOI: 10.1002/anie.202402344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Indexed: 04/24/2024]
Abstract
A hitherto unknown series of air stable, π-conjugated, remarkably bent tetra-cation tetra-radical intermolecular Fe(III) μ-oxo tetranuclear complex, isolated from the dication diradical diiron(III) porphyrin dimers, has been synthesised and spectroscopically characterised along with single crystal X-ray structure determination of two such molecules. These species facilitate long-range charge/radical delocalisation through the bridge across the entire tetranuclear unit manifesting an unusually intense NIR band. Assorted spin states of Fe(III) centres are stabilised within these unique tetranuclear frameworks: terminal six-coordinate iron centres stabilise the admixed intermediate spin states while the central five-coordinate iron centres stabilise the high-spin states. Variable temperature magnetic susceptibility measurements indicated strong antiferromagnetic coupling for the Fe(III)-O-Fe(III) unit while the exchange interactions between the Fe centres and the porphyrin π-cation radicals are weaker as supported both by magnetic data and DFT calculations. The nature of orbital overlap between the SOMOs of Fe(III) and π* orbital of the porphyrin was found to rationalise the observed exchange coupling, establishing such a complex magnetic exchange in this tetranuclear model with a significant bioinorganic relevance.
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Affiliation(s)
- Sabyasachi Sarkar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Rupesh Kumar Tiwari
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Deepannita Samanta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Tapas Guchhait
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - E Carolina Sañudo
- Secció de Química Inorgànica, Department de Química Inorgànica i Orgànica, Facultat de Química, Universitat de Barcelona, C/Martí i Franqués 1-11, 08028, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia, IN2UB, Universitat de Barcelona, C/Martí i Franqués 1-11, 08028, Barcelona, Spain
| | - Gopalan Rajaraman
- Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, 400076, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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4
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Chakraborty P, Ghosh N, Awasthi N, Rath SP. Spin-Flip via Subtle Electronic Perturbation in Axially Ligated Diiron(III) Porphyrin Dimer. Chemistry 2024; 30:e202400266. [PMID: 38407531 DOI: 10.1002/chem.202400266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 02/24/2024] [Accepted: 02/26/2024] [Indexed: 02/27/2024]
Abstract
Spin state switching in the metal center is a crucial phenomenon in many enzymatic reactions in biology. The spin state alteration, a critical step in cytochrome P450 catalysis, is driven most likely through a weak perturbation upon substrate binding in the enzyme, which is still not well clarified. In the current work, the spin state transition of iron(III) from high to intermediate via an admixed state is observed upon a subtle electronic perturbation to the sulphonate moieties coordinated axially to a diiron(III)porphyrin dimer. While electron-donating substituents stabilize the high-spin state of iron(III), strongly electron-withdrawing groups stabilize an intermediate-spin state, whereas the moderate electron-withdrawing nature of axial ligands resulted in an admixed state. Confirmation of the molecular structures and their spin states have been made utilizing single-crystal X-ray structure analysis, Mössbauer, magnetic, EPR, and 1H NMR spectroscopic investigations. The position of the signals of the porphyrin macrocycle in the paramagnetic 1H NMR is found to be very characteristic of the spin state of the iron center in solution. The Curie plot for the pure high-spin complexes shows the signals' temperature dependency in line with the Curie law. Conversely, the pure intermediate-spin state of iron exhibits an anti-Curie temperature dependence, whereas the admixed-spin state of iron displays significant curvature of the lines in the Curie plot. An extensive DFT analysis displays a linear dependence between the energy difference between dx 2 - y 2 ${{_{x{^{2}}- y{^{2}}}}}$ and dz 2 ${{_{z{^{2}}}}}$ orbital versus Fe-Npor distance for the complexes reported here. Furthermore, a strong linear correlation between the Fe-O distance and the spin density over the oxygen atom, as well as the Fe-Npor distance for the complexes, has been observed. Thus, a slight electronic perturbation at the axial ligand of the diheme resulted in a large change in the electronic structures with a spin-flip. This is at par with the metalloenzymes, which employ minute perturbations around the periphery of the active sites, leading to spin state transitions.
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Affiliation(s)
- Paulami Chakraborty
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016
| | - Niva Ghosh
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016
| | - Nidhi Awasthi
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016
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5
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Barreiro DS, Oliveira RN, Pauleta SR. Bacterial peroxidases – Multivalent enzymes that enable the use of hydrogen peroxide for microaerobic and anaerobic proliferation. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2023.215114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/01/2023]
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Yanai K, Hada M, Fujii H. Electric field effect of positive and negative charges of substituents on electronic structure and reactivity of oxoiron(IV) porphyrin π-cation radical complex. J Inorg Biochem 2023; 244:112208. [PMID: 37037142 DOI: 10.1016/j.jinorgbio.2023.112208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/07/2023] [Accepted: 04/03/2023] [Indexed: 04/08/2023]
Abstract
Electric field effect by the positive and negative changes near the active site is an important factor for controlling the reactivity of metalloenzymes. Previously, we reported that the positive charge of the N-methyl-2-pyridinium cation increases the reactivity of oxoiron(IV) porphyrin π-cation radical complex (Compound I), due to the attractive Coulomb interaction with electrons in Compound I. To further investigate the electric field effect, we study here the effect of the negative charge of the sulfonate group on the electronic structure and reactivity using Compound I of meso-tetrakis(2,4,6-trimethyl-3-sulfonatophenyl)porphyrin (TMPS-I). Although Compound I has been known as a very unstable complex, TMPS-I is very stable in 0.1 M acetate buffer at pH = 6. The half-life of TMPS-I is estimated to be 6.9 × 103 s, which is the longest in Compound I previously reported. The redox potential of TMPS-I is estimated to be 0.76 V vs SCE in phosphate buffer, pH = 10. Kinetic analysis with stopped-flow technique indicates TMPS-I is less reactive than Compounds I reported previously. However, 1H NMR and EPR spectra of TMPS-I are very close to those of Compounds I reported previously. The DFT calculations show that the orbital energy of Compound I is drastically altered by the positive and negative charges on the meso-phenyl group, suggesting the electric field effect. The difference of the reactivity of Compound I can be rationalized with the change of the orbital energy caused by the intramolecular electric field effect of the positive and negative charges.
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Affiliation(s)
- Kanae Yanai
- Department of Chemistry, Biology, and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan
| | - Masahiko Hada
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Hachioji 192-0397, Japan
| | - Hiroshi Fujii
- Department of Chemistry, Biology, and Environmental Sciences, Graduate School of Humanities and Sciences, Nara Women's University, Nara 630-8506, Japan.
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Sarkar S, Shah Tuglak Khan F, Guchhait T, Rath SP. Binuclear complexes with single M-F-M bridge (M: Fe, Mn, and Cu): A critical analysis of the impact of fluoride for isoelectronic hydroxide substitution. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.215003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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8
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Sil D, Khan FST, Rath SP. Effect of intermacrocyclic interactions: Modulation of metal spin-state in oxo/hydroxo/fluoro-bridged diiron(III)/dimanganese(III) porphyrin dimers. ADVANCES IN INORGANIC CHEMISTRY 2023. [DOI: 10.1016/bs.adioch.2022.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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9
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Terner J, Thomas KE, Vazquez-Lima H, Ghosh A. Structure-sensitive marker bands of metallocorroles: A resonance Raman study of manganese and Gold Corrole derivatives. J Inorg Biochem 2022; 231:111783. [DOI: 10.1016/j.jinorgbio.2022.111783] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 02/23/2022] [Accepted: 02/26/2022] [Indexed: 11/30/2022]
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Yamaguchi T, Akao K, Koutsioubas A, Frielinghaus H, Kohzuma T. Open-Bundle Structure as the Unfolding Intermediate of Cytochrome c' Revealed by Small Angle Neutron Scattering. Biomolecules 2022; 12:95. [PMID: 35053243 PMCID: PMC8774185 DOI: 10.3390/biom12010095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 12/31/2021] [Accepted: 01/04/2022] [Indexed: 11/27/2022] Open
Abstract
The dynamic structure changes, including the unfolding, dimerization, and transition from the compact to the open-bundle unfolding intermediate structure of Cyt c', were detected by a small-angle neutron scattering experiment (SANS). The structure of Cyt c' was changed into an unstructured random coil at pD = 1.7 (Rg = 25 Å for the Cyt c' monomer). The four-α-helix bundle structure of Cyt c' at neutral pH was transitioned to an open-bundle structure (at pD ~13), which is given by a numerical partial scattering function analysis as a joint-clubs model consisting of four clubs (α-helices) connected by short loops. The compactly folded structure of Cyt c' (radius of gyration, Rg = 18 Å for the Cyt c' dimer) at neutral or mildly alkaline pD transited to a remarkably larger open-bundle structure at pD ~13 (Rg = 25 Å for the Cyt c' monomer). The open-bundle structure was also supported by ab initio modeling.
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Affiliation(s)
- Takahide Yamaguchi
- Institute of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512, Ibaraki, Japan; (T.Y.); (K.A.)
- Frontier Research Center of Applied Atomic Sciences, Ibaraki University, 162-1 Shirakata, Tokai 319-1106, Ibaraki, Japan
| | - Kouhei Akao
- Institute of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512, Ibaraki, Japan; (T.Y.); (K.A.)
| | - Alexandros Koutsioubas
- Jülich Centre for Neutron Science JCNS-4 at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, D-85747 Garching, Germany; (A.K.); (H.F.)
| | - Henrich Frielinghaus
- Jülich Centre for Neutron Science JCNS-4 at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, D-85747 Garching, Germany; (A.K.); (H.F.)
| | - Takamitsu Kohzuma
- Institute of Quantum Beam Science, Graduate School of Science and Engineering, Ibaraki University, 2-1-1 Bunkyo, Mito 310-8512, Ibaraki, Japan; (T.Y.); (K.A.)
- Frontier Research Center of Applied Atomic Sciences, Ibaraki University, 162-1 Shirakata, Tokai 319-1106, Ibaraki, Japan
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11
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Lugosan A, Todtz SR, Alcázar A, Zeller M, Devery JJ, Lee WT. Synthesis and characterization of trigonal bipyramidal Fe III complexes and their solution behavior. Polyhedron 2021; 208. [PMID: 34566234 DOI: 10.1016/j.poly.2021.115384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
A series of air-stable trigonal bipyramidal FeIII complexes supported by a redox non-innocent NNN pincer ligand, Cz tBu(PyrR)2 - (R = iPr, Me, or H), were synthesized, fully characterized, and utilized for the investigation of the interaction between acetone and the FeIII center. The magnetic moments determined from the paramagnetic 1H NMR spectra in conjunction with EPR and Mössbauer spectroscopy indicate the presence of a high-spin ferric center. Cyclic voltammetry studies feature two quasi-reversible events corresponding to a metal-centered FeIII/II reduction around -0.40 V (vs. Fc) and a ligand-centered Cz tBu(PyrR)2/Cz tBu(PyrR)2 •+ oxidation at potentials near +0.70 V (vs. Fc). UV-Visible spectroscopy in CH2Cl2 showcases ligand-metal charge transfer (LMCT) bands, as well as coordination of acetone to Cz tBu(PyrH)2FeCl2. In situ IR spectroscopy and solution conductivity (κ) measurements of Cz tBu(PyrR)2FeCl2 with varied equivalents of acetone reveal that acetone is weakly associated with the iron center.
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Affiliation(s)
- Adriana Lugosan
- Department of Chemistry & Biochemistry, Loyola University Chicago, Flanner Hall, 1068 W Sheridan Rd, Chicago, IL 60660, United States
| | - Sophi R Todtz
- Department of Chemistry & Biochemistry, Loyola University Chicago, Flanner Hall, 1068 W Sheridan Rd, Chicago, IL 60660, United States
| | - Andrew Alcázar
- Department of Chemistry & Biochemistry, Loyola University Chicago, Flanner Hall, 1068 W Sheridan Rd, Chicago, IL 60660, United States
| | - Matthias Zeller
- Department of Chemistry, Purdue University, X-ray Crystallography, 560 Oval Drive, West Lafayette, IN 47907, United States
| | - James J Devery
- Department of Chemistry & Biochemistry, Loyola University Chicago, Flanner Hall, 1068 W Sheridan Rd, Chicago, IL 60660, United States
| | - Wei-Tsung Lee
- Department of Chemistry & Biochemistry, Loyola University Chicago, Flanner Hall, 1068 W Sheridan Rd, Chicago, IL 60660, United States
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Khan FST, Samanta D, Chandel D, Shah SJ, Rath SP. Heme-Heme Interactions in Diheme Cytochromes: Effect of Mixed-Axial Ligation on the Electronic Structure and Electrochemical Properties. Inorg Chem 2021; 60:12870-12882. [PMID: 34370470 DOI: 10.1021/acs.inorgchem.1c01215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Diheme cytochromes, the simplest members in the multiheme family, play substantial biochemical roles in enzymatic catalysis as well as in electron transfer. A series of diiron(III) porphyrin dimers have been synthesized as active site analogues of diheme cytochromes. The complexes contain six-coordinated iron(III) having thiophenol and imidazole at the fifth and sixth coordination sites, respectively. The iron centers in the complexes have been found to be in a low-spin state, as confirmed through solid-state Mössbauer and electron paramagnetic resonance (EPR) spectroscopic investigations. Mössbauer quadrupole splitting of complexes having mixed ligands is substantially larger than that observed when both axial ligands are the same. Rhombic types of EPR spectra with narrow separation between gx, gy, and gz clearly distinguish heme thiolate coordination compared to bis(imidazole)-ligated low-spin heme centers. The redox potential in diheme cytochromes has been found to be tuned by interheme interactions along with the nature of axial ligands. The effect of mixed-axial ligation within the diiron(III) porphyrin dimers is demonstrated by a positive shift in the Fe(III)/Fe(II) redox couple upon thiophenolate coordination compared to their bis(imidazole) analogues. The pKa of the imidazole also decides the extent of the shift for the Fe(III)/Fe(II) couple, while the potential of the mixed-ligated diiron(III) porphyrin dimer is more positive compared to their monomeric analogue. A variation of around 1.1 V for the Fe(III)/Fe(II) redox potential in the diiron(III) porphyrin dimer can be achieved with the combined effect of axial ligation and a metal spin state, while such a large variation in the redox potential, compared to their monomeric analogues, is attributed to the heme-heme interactions observed in dihemes. Moreover, theoretical calculations also support the experimental shifts in the redox potential values.
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Affiliation(s)
| | - Deepannita Samanta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Dolly Chandel
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Syed Jehanger Shah
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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Shafizadeh N, Crestoni ME, de la Lande A, Soep B. Heme ligation in the gas phase. INT REV PHYS CHEM 2021. [DOI: 10.1080/0144235x.2021.1952006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
| | - Maria Elisa Crestoni
- Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma “La Sapienza”, Roma, Italy
| | | | - Benoît Soep
- ISMO-CNRS, Université Paris Saclay, Orsay Cedex, France
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14
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Kumar A, Usman M, Samanta D, Rath SP. Through Bridge Spin Coupling in Homo- and Heterobimetallic Porphyrin Dimers upon Stepwise Oxidations: A Spectroscopic and Theoretical Investigation. Chemistry 2021; 27:11428-11441. [PMID: 34061401 DOI: 10.1002/chem.202101384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Indexed: 12/16/2022]
Abstract
We have described copper(II)-iron(III) and copper(II)-manganese(III) heterobimetallic porphyrin dimers and compared them with the corresponding homobimetallic analogs. UV-visible spectra are very distinct in the heterometallic species while electrochemical studies demonstrate that these species, as compared to the homobimetallic analog, are much easier to oxidize. Combined Mössbauer, EPR, NMR, magnetic and UV-visible spectroscopic studies show that upon 2e-oxidation of the heterobimetallic complexes only ring-centered oxidation occurs. The energy differences between HOMO and LUMO are linearly dependent with the low-energy NIR band obtained for the 2e-oxidized complexes. Also, strong electronic communication between two porphyrin rings through the bridge facilitates coupling between various unpaired spins present while the coupling model depends on the nature of metal ions used. While unpaired spins of Fe(III) and the porphyrin π-cation radical are strongly antiferromagnetically coupled, such coupling is rather weak between Mn(III) and a porphyrin π-cation radical. Moreover, the coupling between two π-cation radicals are much stronger in the 2e-oxidized complexes of dimanganese(III) and copper(II)-manganese(III) porphyrin dimers as compared to their diiron(III) and copper(II)-iron(III) analogs. Furthermore, coupling between the unpaired spins of a π-cation radical and copper(II) is much stronger in the 2e-oxidized complex of copper(II)-iron(III) porphyrin dimer as compared to its copper(II)-manganese(III) analog. The Mulliken spin density distributions in 2e-oxidized homo- and heterobimetallic complexes show symmetric and asymmetric spread between the two macrocycles, respectively. In both the 2e-oxidized heterobimetallic complexes, the Cu(II) porphyrin center acts as a charge donor while Fe(III)/Mn(III) porphyrin center act as a charge acceptor. The experimental observations are also strongly supported by DFT calculations.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Mohammad Usman
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Deepannita Samanta
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
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15
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Leone L, Chino M, Nastri F, Maglio O, Pavone V, Lombardi A. Mimochrome, a metalloporphyrin‐based catalytic Swiss knife†. Biotechnol Appl Biochem 2020; 67:495-515. [DOI: 10.1002/bab.1985] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 07/09/2020] [Indexed: 12/20/2022]
Affiliation(s)
- Linda Leone
- Department of Chemical Sciences University of Napoli “Federico II” Napoli Italy
| | - Marco Chino
- Department of Chemical Sciences University of Napoli “Federico II” Napoli Italy
| | - Flavia Nastri
- Department of Chemical Sciences University of Napoli “Federico II” Napoli Italy
| | - Ornella Maglio
- Department of Chemical Sciences University of Napoli “Federico II” Napoli Italy
- IBB ‐ National Research Council Napoli Italy
| | - Vincenzo Pavone
- Department of Chemical Sciences University of Napoli “Federico II” Napoli Italy
| | - Angela Lombardi
- Department of Chemical Sciences University of Napoli “Federico II” Napoli Italy
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16
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Halcrow MA. Manipulating metal spin states for biomimetic, catalytic and molecular materials chemistry. Dalton Trans 2020; 49:15560-15567. [DOI: 10.1039/d0dt01919d] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The relationship between ligand design and spin state in base metal compounds is surveyed. Implications and applications of these principles for light-harvesting dyes, catalysis and materials chemistry are summarised.
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17
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Cruddas J, Powell BJ. Spin-State Ice in Elastically Frustrated Spin-Crossover Materials. J Am Chem Soc 2019; 141:19790-19799. [DOI: 10.1021/jacs.9b09191] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jace Cruddas
- School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - B. J. Powell
- School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072, Australia
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18
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Sahoo D, Roy S, Khan FST, Singh AK, Rath SP. Stabilizing intermediate-spin state in iron(III) porphyrins. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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19
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Axial ligand mediated switchable rotary motions in a ferrocene-bridged diiron(III) porphyrin dimer. J Organomet Chem 2019. [DOI: 10.1016/j.jorganchem.2019.05.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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20
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Nóbrega CS, Pauleta SR. Reduction of hydrogen peroxide in gram-negative bacteria - bacterial peroxidases. Adv Microb Physiol 2019; 74:415-464. [PMID: 31126534 DOI: 10.1016/bs.ampbs.2019.02.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Bacteria display an array of enzymes to detoxify reactive oxygen species that cause damage to DNA and to other biomolecules leading to cell death. Hydrogen peroxide is one of these species, with endogenous and exogenous sources, such as lactic acid bacteria, oxidative burst of the immune system or chemical reactions at oxic-anoxic interfaces. The enzymes that detoxify hydrogen peroxide will be the focus of this review, with special emphasis on bacterial peroxidases that reduce hydrogen peroxide to water. Bacterial peroxidases are periplasmic cytochromes with either two or three c-type haems, which have been classified as classical and non-classical bacterial peroxidases, respectively. Most of the studies have been focus on the classical bacterial peroxidases, showing the presence of a reductive activation in the presence of calcium ions. Mutagenesis studies have clarified the catalytic mechanism of this enzyme and were used to propose an intramolecular electron transfer pathway, with far less being known about the intermolecular electron transfer that occurs between reduced electron donors and the enzyme. The physiological function of these enzymes was not very clear until it was shown, for the non-classical bacterial peroxidase, that this enzyme is required for the bacteria to use hydrogen peroxide as terminal electron acceptor under anoxic conditions. These non-classical bacterial peroxidases are quinol peroxidases that do not require reductive activation but need calcium ions to attain maximum activity and share similar catalytic intermediates with the classical bacterial peroxidases.
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Affiliation(s)
- Cláudia S Nóbrega
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Sofia R Pauleta
- Microbial Stress Lab, UCIBIO, REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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21
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Khan FST, Kumar A, Lai D, Rath SP. Ethene-bridged diiron porphyrin dimer as models of diheme cytochrome c: Structure-function correlation and modulation of heme redox potential. Inorganica Chim Acta 2019. [DOI: 10.1016/j.ica.2018.09.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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22
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Khan FST, Shah SJ, Bhowmik S, Reinhard FGC, Sainna MA, de Visser SP, Rath SP. Equatorial ligand plane perturbations lead to a spin-state change in an iron(iii) porphyrin dimer. Dalton Trans 2019; 48:6353-6357. [DOI: 10.1039/c9dt01182j] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A complete reversal of the spin state of iron(iii) is observed upon a small change to the diporphyrin bridge from ethane to ethene by keeping all other factors intact.
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Affiliation(s)
| | - Syed Jehanger Shah
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Susovan Bhowmik
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Fabián G. Cantú Reinhard
- The Manchester Institute of Biotechnology and the School of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester M1 7DN
- UK
| | - Mala A. Sainna
- The Manchester Institute of Biotechnology and the School of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester M1 7DN
- UK
| | - Sam P. de Visser
- The Manchester Institute of Biotechnology and the School of Chemical Engineering and Analytical Science
- The University of Manchester
- Manchester M1 7DN
- UK
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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23
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Kumar A, Banerjee S, Sarkar S, Rath SP. Stepwise oxidations of a nickel(ii)–iron(iii) heterobimetallic porphyrin dimer: structure, spectroscopic and theoretical investigation. Dalton Trans 2019; 48:10089-10103. [DOI: 10.1039/c9dt01776c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel nickel(ii)–iron(iii) heterobimetallic ethene-bridged porphyrin dimer has been synthesized which upon two-electron oxidation produces a nickel(ii)–iron(iii) dication diradical complex where radicals undergo extensive conjugation through the bridge for all possible interactions.
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Affiliation(s)
- Amit Kumar
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sayantani Banerjee
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sabyasachi Sarkar
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
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24
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Khan FST, Banerjee S, Kumar D, Rath SP. Diheme Cytochrome c: Structure–Function Correlation and Effect of Heme−Heme Interactions. Inorg Chem 2018; 57:11498-11510. [DOI: 10.1021/acs.inorgchem.8b01368] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Sayantani Banerjee
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India
| | - Devesh Kumar
- Department of Physics, School for Physical and Decision Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow-226025, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, India
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25
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Modulation of iron spin in ethane-bridged diiron(III) porphyrin dimer: anion dependent spin state switching. J CHEM SCI 2018. [DOI: 10.1007/s12039-018-1488-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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26
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Lai D, Khan FST, Rath SP. Multiheme proteins: effect of heme–heme interactions. Dalton Trans 2018; 47:14388-14401. [DOI: 10.1039/c8dt00518d] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
This Frontier illustrates a brief personal account on the effect of heme–heme interactions in dihemes which thereby discloses some of the evolutionary design principles involved in multiheme proteins for their diverse structures and functions.
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Affiliation(s)
- Dipti Lai
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | | | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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27
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Construction and in vivo assembly of a catalytically proficient and hyperthermostable de novo enzyme. Nat Commun 2017; 8:358. [PMID: 28842561 PMCID: PMC5572459 DOI: 10.1038/s41467-017-00541-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 07/07/2017] [Indexed: 11/08/2022] Open
Abstract
Although catalytic mechanisms in natural enzymes are well understood, achieving the diverse palette of reaction chemistries in re-engineered native proteins has proved challenging. Wholesale modification of natural enzymes is potentially compromised by their intrinsic complexity, which often obscures the underlying principles governing biocatalytic efficiency. The maquette approach can circumvent this complexity by combining a robust de novo designed chassis with a design process that avoids atomistic mimicry of natural proteins. Here, we apply this method to the construction of a highly efficient, promiscuous, and thermostable artificial enzyme that catalyzes a diverse array of substrate oxidations coupled to the reduction of H2O2. The maquette exhibits kinetics that match and even surpass those of certain natural peroxidases, retains its activity at elevated temperature and in the presence of organic solvents, and provides a simple platform for interrogating catalytic intermediates common to natural heme-containing enzymes.Catalytic mechanisms of enzymes are well understood, but achieving diverse reaction chemistries in re-engineered proteins can be difficult. Here the authors show a highly efficient and thermostable artificial enzyme that catalyzes a diverse array of substrate oxidations coupled to the reduction of H2O2.
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28
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Oxo- and hydroxo-bridged diiron(III) porphyrin dimers: Inorganic and bio-inorganic perspectives and effects of intermacrocyclic interactions. Coord Chem Rev 2017. [DOI: 10.1016/j.ccr.2017.02.008] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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29
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Reuillard B, Ly KH, Hildebrandt P, Jeuken LJC, Butt JN, Reisner E. High Performance Reduction of H 2O 2 with an Electron Transport Decaheme Cytochrome on a Porous ITO Electrode. J Am Chem Soc 2017; 139:3324-3327. [PMID: 28221032 PMCID: PMC5411108 DOI: 10.1021/jacs.6b12437] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Indexed: 11/28/2022]
Abstract
The decaheme cytochrome MtrC from Shewanella oneidensis MR-1 immobilized on an ITO electrode displays unprecedented H2O2 reduction activity. Although MtrC showed lower peroxidase activity in solution compared to horseradish peroxidase, the ten heme cofactors enable excellent electronic communication and a superior activity on the electrode surface. A hierarchical ITO electrode enabled optimal immobilization of MtrC and a high current density of 1 mA cm-2 at 0.4 V vs SHE could be obtained at pH 6.5 (Eonset = 0.72 V). UV-visible and Resonance Raman spectroelectrochemical studies suggest the formation of a high valent iron-oxo species as the catalytic intermediate. Our findings demonstrate the potential of multiheme cytochromes to catalyze technologically relevant reactions and establish MtrC as a new benchmark in biotechnological H2O2 reduction with scope for applications in fuel cells and biosensors.
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Affiliation(s)
- Bertrand Reuillard
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Khoa H. Ly
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
| | - Peter Hildebrandt
- Institut
für Chemie, Technische Universität
Berlin, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Lars J. C. Jeuken
- School
of Biomedical Sciences and the Astbury Centre, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Julea N. Butt
- School
of
Chemistry and School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom
| | - Erwin Reisner
- Department
of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United
Kingdom
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30
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Takashina A, Tiedemann MT, Unno M, Yamaguchi T, Stillman MJ, Kohzuma T. The pH Dependent Protein Structure Transitions and Related Spin-State Transition of Cytochrome c′ from Alcaligenes xylosoxidansNCIMB 11015. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2017. [DOI: 10.1246/bcsj.20160316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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31
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Moguilevski A, Wilke M, Grell G, Bokarev SI, Aziz SG, Engel N, Raheem AA, Kühn O, Kiyan IY, Aziz EF. Ultrafast Spin Crossover in [FeII
(bpy)3
]2+
: Revealing Two Competing Mechanisms by Extreme Ultraviolet Photoemission Spectroscopy. Chemphyschem 2017; 18:465-469. [DOI: 10.1002/cphc.201601396] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Alexandre Moguilevski
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq); Institute of Methods for Material Development; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15 12489 Berlin Germany
| | - Martin Wilke
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq); Institute of Methods for Material Development; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15 12489 Berlin Germany
| | - Gilbert Grell
- Institute of Physics; University of Rostock; Albert-Einstein-Str. 23-24 18059 Rostock Germany
| | - Sergey I. Bokarev
- Institute of Physics; University of Rostock; Albert-Einstein-Str. 23-24 18059 Rostock Germany
| | - Saadullah G. Aziz
- Chemistry Department, Faculty of Science; King Abdulaziz University; 21589 Jeddah Saudi Arabia
| | - Nicholas Engel
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq); Institute of Methods for Material Development; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15 12489 Berlin Germany
| | - Azhr A. Raheem
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq); Institute of Methods for Material Development; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15 12489 Berlin Germany
| | - Oliver Kühn
- Institute of Physics; University of Rostock; Albert-Einstein-Str. 23-24 18059 Rostock Germany
| | - Igor Yu. Kiyan
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq); Institute of Methods for Material Development; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15 12489 Berlin Germany
| | - Emad F. Aziz
- Joint Laboratory for Ultrafast Dynamics in Solutions and at Interfaces (JULiq); Institute of Methods for Material Development; Helmholtz-Zentrum Berlin; Albert-Einstein-Str. 15 12489 Berlin Germany
- Department of Physics; Freie Universität Berlin; Arnimallee 14 14195 Berlin Germany
- School of Chemistry; Monash University; Clayton 3800 VIC Australia
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32
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Khan FST, Guchhait T, Sasmal S, Rath SP. Hydroxo-bridged diiron(iii) and dimanganese(iii) bisporphyrins: modulation of metal spins by counter anions. Dalton Trans 2017; 46:1012-1037. [DOI: 10.1039/c6dt03829h] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A brief account has been presented on how the inter-heme interactions in μ-hydroxo diiron(iii) bisporphyrins and counter anions can induce significant change in the structure and properties including the iron spin state without affecting the overall topology.
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Affiliation(s)
| | - Tapas Guchhait
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Sujit Sasmal
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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33
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Khan FST, Pandey AK, Rath SP. Remarkable Anion-Dependent Spin-State Switching in Diiron(III) μ-Hydroxo Bisporphyrins: What Role do Counterions Play? Chemistry 2016; 22:16124-16137. [PMID: 27682429 DOI: 10.1002/chem.201603163] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Indexed: 12/20/2022]
Abstract
Addition of 2,4,6-trinitrophenol (HTNP) to an ethene-bridged diiron(III) μ-oxo bisporphyrin (1) in CH2 Cl2 initially leads to the formation of diiron(III) μ-hydroxo bisporphyrin (2⋅TNP) with a phenolate counterion that, after further addition of HTNP or dissolution in a nonpolar solvent, converts to a diiron(III) complex with axial phenoxide coordination (3⋅(TNP)2 ). The progress of the reaction from μ-oxo to μ-hydroxo to axially ligated complex has been monitored in solution by using 1 H NMR spectroscopy because their signals appear in three different and distinct spectral regions. The X-ray structure of 2⋅TNP revealed that the nearly planar TNP counterion fits perfectly within the bisporphyrin cavity to form a strong hydrogen bond with the μ-hydroxo group, which thus stabilizes the two equivalent iron centers. In contrast, such counterions as I5 , I3 , BF4 , SbF6 , and PF6 are found to be tightly associated with one of the porphyrin rings and, therefore, stabilize two different spin states of iron in one molecule. A spectroscopic investigation of 2⋅TNP has revealed the presence of two equivalent iron centers with a high-spin state (S=5/2) in the solid state that converts to intermediate spin (S=3/2) in solution. An extensive computational study by using a range of DFT methods was performed on 2⋅TNP and 2+ , and clearly supports the experimentally observed spin flip triggered by hydrogen-bonding interactions. The counterion is shown to perturb the spin-state ordering through, for example, hydrogen-bonding interactions, switched positions between counterion and axial ligand, ion-pair interactions, and charge polarization. The present investigation thus provides a clear rationalization of the unusual counterion-specific spin states observed in the μ-hydroxo bisporphyrins that have so far remained the most outstanding issue.
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Affiliation(s)
| | - Anjani Kumar Pandey
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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34
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Sil D, Khan FST, Rath SP. Effect of Inter-Porphyrin Distance on Spin-State in Diiron(III) μ-Hydroxo Bisporphyrins. Chemistry 2016; 22:14585-97. [DOI: 10.1002/chem.201602018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Indexed: 12/16/2022]
Affiliation(s)
- Debangsu Sil
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | | | - Sankar Prasad Rath
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
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35
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Sil D, Kumar A, Rath SP. Diiron(III)-μ-Fluoro Bisporphyrins: Effect of Bridging Ligand on the Metal Spin State. Chemistry 2016; 22:11214-23. [DOI: 10.1002/chem.201600786] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Debangsu Sil
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | - Amit Kumar
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
| | - Sankar Prasad Rath
- Department of Chemistry; Indian Institute of Technology Kanpur; Kanpur- 208016 India
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36
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Sahoo D, Guchhait T, Rath SP. Spin Modulation in Highly Distorted FeIIIPorphyrinates by Using Axial Coordination and Their π-Cation Radicals. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600255] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dipankar Sahoo
- Department of Chemistry; Indian Institute of Technology Kanpur; 208016 Kanpur India
| | - Tapas Guchhait
- Department of Chemistry; Indian Institute of Technology Kanpur; 208016 Kanpur India
| | - Sankar Prasad Rath
- Department of Chemistry; Indian Institute of Technology Kanpur; 208016 Kanpur India
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37
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Sahoo D, Singh AK, Rath SP. Binuclear Highly Distorted Iron(III) Porphyrins Bridged by the Dianions of Hydroquinones: Role of the Bridge in Electronic Communication. Eur J Inorg Chem 2016. [DOI: 10.1002/ejic.201600257] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Dipankar Sahoo
- Department of Chemistry; Indian Institute of Technology Kanpur; 208016 Kanpur India
| | - Akhil Kumar Singh
- Department of Chemistry; Indian Institute of Technology Kanpur; 208016 Kanpur India
| | - Sankar Prasad Rath
- Department of Chemistry; Indian Institute of Technology Kanpur; 208016 Kanpur India
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38
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Sil D, Bhowmik S, Khan FST, Rath SP. Experimental and Theoretical Investigation of a Series of Novel Dimanganese(III) μ-Hydroxo Bisporphyrins: Magneto–Structural Correlation and Effect of Metal Spin on Porphyrin Core Deformation. Inorg Chem 2016; 55:3239-51. [DOI: 10.1021/acs.inorgchem.5b02226] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Debangsu Sil
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Susovan Bhowmik
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | | | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
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39
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Sil D, Dey S, Kumar A, Bhowmik S, Rath SP. Oxidation triggers extensive conjugation and unusual stabilization of two di-heme dication diradical intermediates: role of bridging group for electronic communication. Chem Sci 2015; 7:1212-1223. [PMID: 29910877 PMCID: PMC5975787 DOI: 10.1039/c5sc03120f] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/26/2015] [Indexed: 11/21/2022] Open
Abstract
Synthetic analogs of diheme enzyme MauG have been reported. Unlike the bis-Fe(iv) state in MauG, the 2e-oxidation stabilizes two ferric hemes, each coupled with a porphyrin π-cation radical.
MauG is a diheme enzyme that utilizes two covalently bound c-type hemes to catalyse the biosynthesis of the protein-derived cofactor tryptophan tryptophylquinone. The two hemes are physically separated by 14.5 Å and a hole-hopping mechanism is proposed in which a tryptophan residue located between the hemes undergoes reversible oxidation and reduction to increase the effective electronic coupling element and enhance the rate of reversible electron transfer between the hemes in bis-Fe(iv) MauG. The present work describes the structure and spectroscopic investigation of 2e-oxidations of the synthetic diheme analogs in which two heme centers are covalently connected through a conjugated ethylene bridge that leads to the stabilization of two unusual trans conformations (U and P′ forms) with different and distinct spectroscopic and geometric features. Unlike in MauG, where the two oxidizing equivalents are distributed within the diheme system giving rise to the bis-Fe(iv) redox state, the synthetic analog stabilizes two ferric hemes, each coupled with a porphyrin cation radical, a scenario resembling the binuclear dication diradical complex. Interestingly, charge resonance-transition phenomena are observed here both in 1e and 2e-oxidised species from the same system, which are also clearly distinguishable by their relative position and intensity. Detailed UV-vis-NIR, X-ray, Mössbauer, EPR and 1H NMR spectroscopic investigations as well as variable temperature magnetic studies have unraveled strong electronic communications between two porphyrin π-cation radicals through the bridging ethylene group. The extensive π-conjugation also allows antiferromagnetic coupling between iron(iii) centers and porphyrin radical spins of both rings. DFT calculations revealed extended π-conjugation and H-bonding interaction as the major factors in controlling the stability of the conformers.
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Affiliation(s)
- Debangsu Sil
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Soumyajit Dey
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Amit Kumar
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Susovan Bhowmik
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
| | - Sankar Prasad Rath
- Department of Chemistry , Indian Institute of Technology Kanpur , Kanpur-208016 , India . ;
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40
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Sahoo D, Quesne MG, de Visser SP, Rath SP. Hydrogen-Bonding Interactions Trigger a Spin-Flip in Iron(III) Porphyrin Complexes. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 127:4878-4882. [PMID: 26109743 PMCID: PMC4470476 DOI: 10.1002/ange.201411399] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Indexed: 11/16/2022]
Abstract
A key step in cytochrome P450 catalysis includes the spin-state crossing from low spin to high spin upon substrate binding and subsequent reduction of the heme. Clearly, a weak perturbation in P450 enzymes triggers a spin-state crossing. However, the origin of the process whereby enzymes reorganize their active site through external perturbations, such as hydrogen bonding, is still poorly understood. We have thus studied the impact of hydrogen-bonding interactions on the electronic structure of a five-coordinate iron(III) octaethyltetraarylporphyrin chloride. The spin state of the metal was found to switch reversibly between high (S=5/2) and intermediate spin (S=3/2) with hydrogen bonding. Our study highlights the possible effects and importance of hydrogen-bonding interactions in heme proteins. This is the first example of a synthetic iron(III) complex that can reversibly change its spin state between a high and an intermediate state through weak external perturbations.
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Affiliation(s)
- Dipankar Sahoo
- Department of Chemistry, Indian Institute of Technology KanpurKanpur-208016 (India)
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester131 Princess Street, Manchester M1 7DN (UK)
| | - Matthew G Quesne
- Department of Chemistry, Indian Institute of Technology KanpurKanpur-208016 (India)
- Manchester Institute of Biotechnology and School of Chemical Engineering and Analytical Science, The University of Manchester131 Princess Street, Manchester M1 7DN (UK)
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41
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Kimura Y, Kasuga S, Unno M, Furusawa T, Osoegawa S, Sasaki Y, Ohno T, Wang-Otomo ZY. The roles of C-terminal residues on the thermal stability and local heme environment of cytochrome c' from the thermophilic purple sulfur bacterium Thermochromatium tepidum. PHOTOSYNTHESIS RESEARCH 2015; 124:19-29. [PMID: 25519852 DOI: 10.1007/s11120-014-0069-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 12/11/2014] [Indexed: 06/04/2023]
Abstract
A soluble cytochrome (Cyt) c' from thermophilic purple sulfur photosynthetic bacterium Thermochromatium (Tch.) tepidum exhibits marked thermal tolerance compared with that from the closely related mesophilic counterpart Allochromatium vinosum. Here, we focused on the difference in the C-terminal region of the two Cyts c' and examined the effects of D131 and R129 mutations on the thermal stability and local heme environment of Cyt c' by differential scanning calorimetry (DSC) and resonance Raman (RR) spectroscopy. In the oxidized forms, D131K and D131G mutants exhibited denaturing temperatures significantly lower than that of the recombinant control Cyt c'. In contrast, R129K and R129A mutants denatured at nearly identical temperatures with the control Cyt c', indicating that the C-terminal D131 is an important residue maintaining the enhanced thermal stability of Tch. tepidum Cyt c'. The control Cyt c' and all of the mutants increased their thermal stability upon the reduction. Interestingly, D131K exhibited narrow DSC curves and unusual thermodynamic parameters in both redox states. The RR spectra of the control Cyt c' exhibited characteristic bands at 1,635 and 1,625 cm(-1), ascribed to intermediate spin (IS) and high spin (HS) states, respectively. The IS/HS distribution was differently affected by the D131 and R129 mutations and pH changes. Furthermore, R129 mutants suggested the lowering of their redox potentials. These results strongly indicate that the D131 and R129 residues play significant roles in maintaining the thermal stability and modulating the local heme environment of Tch. tepidum Cyt c'.
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Affiliation(s)
- Yukihiro Kimura
- Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Nada, Kobe, 657-8501, Japan,
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42
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Conformational control of the binding of diatomic gases to cytochrome c'. J Biol Inorg Chem 2015; 20:675-86. [PMID: 25792378 DOI: 10.1007/s00775-015-1253-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/06/2015] [Indexed: 10/23/2022]
Abstract
The cytochromes c' (CYTcp) are found in denitrifying, methanotrophic and photosynthetic bacteria. These proteins are able to form stable adducts with CO and NO but not with O2. The binding of NO to CYTcp currently provides the best structural model for the NO activation mechanism of soluble guanylate cyclase. Ligand binding in CYTcps has been shown to be highly dependent on residues in both the proximal and distal heme pockets. Group 1 CYTcps typically have a phenylalanine residue positioned close to the distal face of heme, while for group 2, this residue is typically leucine. We have structurally, spectroscopically and kinetically characterised the CYTcp from Shewanella frigidimarina (SFCP), a protein that has a distal phenylalanine residue and a lysine in the proximal pocket in place of the more common arginine. Each monomer of the SFCP dimer folds as a 4-alpha-helical bundle in a similar manner to CYTcps previously characterised. SFCP exhibits biphasic binding kinetics for both NO and CO as a result of the high level of steric hindrance from the aromatic side chain of residue Phe 16. The binding of distal ligands is thus controlled by the conformation of the phenylalanine ring. Only a proximal 5-coordinate NO adduct, confirmed by structural data, is observed with no detectable hexacoordinate distal NO adduct.
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43
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Iron(III) and copper(II) complexes of trans-bis(ferrocenyl)porphyrin: Effect of metal ions on long-range electronic communication. J CHEM SCI 2015. [DOI: 10.1007/s12039-015-0785-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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44
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Takashina A, Unno M, Kohzuma T. X-ray Crystallographic Elucidation for the Alkaline High-spin State Transition of Iron(III) Cytochrome c′ from Alcaligenes xylosoxidans NCIMB 11015. CHEM LETT 2015. [DOI: 10.1246/cl.140975] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Masaki Unno
- Institute of Applied Beam Science, Ibaraki University
- Frontier Research Center for Applied Atomic Sciences
| | - Takamitsu Kohzuma
- Institute of Applied Beam Science, Ibaraki University
- Frontier Research Center for Applied Atomic Sciences
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45
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Sahoo D, Quesne MG, de Visser SP, Rath SP. Hydrogen-bonding interactions trigger a spin-flip in iron(III) porphyrin complexes. Angew Chem Int Ed Engl 2015; 54:4796-800. [PMID: 25645603 PMCID: PMC4687417 DOI: 10.1002/anie.201411399] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Indexed: 12/03/2022]
Abstract
A key step in cytochrome P450 catalysis includes the spin-state crossing from low spin to high spin upon substrate binding and subsequent reduction of the heme. Clearly, a weak perturbation in P450 enzymes triggers a spin-state crossing. However, the origin of the process whereby enzymes reorganize their active site through external perturbations, such as hydrogen bonding, is still poorly understood. We have thus studied the impact of hydrogen-bonding interactions on the electronic structure of a five-coordinate iron(III) octaethyltetraarylporphyrin chloride. The spin state of the metal was found to switch reversibly between high (S=5/2) and intermediate spin (S=3/2) with hydrogen bonding. Our study highlights the possible effects and importance of hydrogen-bonding interactions in heme proteins. This is the first example of a synthetic iron(III) complex that can reversibly change its spin state between a high and an intermediate state through weak external perturbations.
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Affiliation(s)
- Dipankar Sahoo
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016 (India)
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46
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Sainna MA, Sil D, Sahoo D, Martin B, Rath SP, Comba P, de Visser SP. Spin-State Ordering in Hydroxo-Bridged Diiron(III)bisporphyrin Complexes. Inorg Chem 2015; 54:1919-30. [DOI: 10.1021/ic502803b] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Mala A. Sainna
- Manchester Institute
of Biotechnology and School of Chemical Engineering and Analytical
Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Debangsu Sil
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Dipankar Sahoo
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Bodo Martin
- Anorganisch-Chemisches Institüt and Interdisciplinary
Center for Scientific Computing (IWR), University of Heidelberg, Im Neuenheimer
Feld 270, 69120 Heidelberg, Germany
| | - Sankar Prasad Rath
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208016, India
| | - Peter Comba
- Anorganisch-Chemisches Institüt and Interdisciplinary
Center for Scientific Computing (IWR), University of Heidelberg, Im Neuenheimer
Feld 270, 69120 Heidelberg, Germany
| | - Sam P. de Visser
- Manchester Institute
of Biotechnology and School of Chemical Engineering and Analytical
Science, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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47
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Drake JL, Kaplan HZ, Wilding MJT, Li B, Byers JA. Spin transitions in bis(amidinato)-N-heterocyclic carbene iron(ii) and iron(iii) complexes. Dalton Trans 2015; 44:16703-7. [DOI: 10.1039/c5dt02440d] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In contrast to high spin pyridyl diimine iron(ii) dichloride complexes, analogous bis(amidinato)-N-heterocyclic carbene iron(ii) and iron(iii) complexes demonstrate complex magnetic behaviour.
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Affiliation(s)
- Jessica L. Drake
- Eugene F. Merkert Chemistry Center
- Department of Chemistry
- Boston College
- Chestnut Hill
- USA
| | - Hilan Z. Kaplan
- Eugene F. Merkert Chemistry Center
- Department of Chemistry
- Boston College
- Chestnut Hill
- USA
| | | | - Bo Li
- Eugene F. Merkert Chemistry Center
- Department of Chemistry
- Boston College
- Chestnut Hill
- USA
| | - Jeffery A. Byers
- Eugene F. Merkert Chemistry Center
- Department of Chemistry
- Boston College
- Chestnut Hill
- USA
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48
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Sahoo D, Rath SP. Controlled generation of highly saddled (porphyrinato)iron(iii) iodide, tri-iodide and one-electron oxidized complexes. Chem Commun (Camb) 2015; 51:16790-3. [DOI: 10.1039/c5cc07111a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Three iron(iii) porphyrinato complexes have been isolated selectively just by varying the iodine concentration, which eventually form the admixed-intermediate (iodo complex), pure intermediate (tri-iodide complex) and high-spin (1e-oxidized complex) states of iron where iodide and/or tri-iodide were used as axial ligands.
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Affiliation(s)
- Dipankar Sahoo
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur-208016
- India
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49
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Fidalgo-Marijuan A, Barandika G, Bazán B, Urtiaga MK, Larrea ES, Iglesias M, Lezama L, Arriortua MI. Heterogeneous catalytic properties of unprecedented μ-O-[FeTCPP]2 dimers (H2TCPP = meso-tetra(4-carboxyphenyl)porphyrin): an unusual superhyperfine EPR structure. Dalton Trans 2015; 44:213-22. [DOI: 10.1039/c4dt02250e] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Solvent accessible volume of the active catalyst μ-O-[FeTCPP]2·nDMF dimer revealing an unusual superhyperfine EPR structure.
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Affiliation(s)
- Arkaitz Fidalgo-Marijuan
- Departamento de Mineralogía y Petrología
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
| | - Gotzone Barandika
- Departamento de Química Inorgánica
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
| | - Begoña Bazán
- Departamento de Mineralogía y Petrología
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
| | - Miren Karmele Urtiaga
- Departamento de Mineralogía y Petrología
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
| | - Edurne S. Larrea
- Departamento de Mineralogía y Petrología
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
| | - Marta Iglesias
- Instituto de Ciencia de Materiales de Madrid-CSIC
- Sor Juana Inés de la Cruz 3
- 28049 Madrid
- Spain
| | - Luis Lezama
- Departamento de Química Inorgánica
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
| | - María Isabel Arriortua
- Departamento de Mineralogía y Petrología
- Facultad de Ciencia y Tecnología
- Universidad del País Vasco (UPV/EHU)
- 48080 Bilbao
- Spain
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50
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Sil D, Rath SP. An ethane-bridged porphyrin dimer as a model of di-heme proteins: inorganic and bioinorganic perspectives and consequences of heme–heme interactions. Dalton Trans 2015; 44:16195-211. [DOI: 10.1039/c5dt00947b] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A brief account of our recent efforts on how inter-heme interactions can possibly change the structure and functional properties of the individual heme centers in a highly flexible ethane-bridged porphyrin dimer has been presented.
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Affiliation(s)
- Debangsu Sil
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
| | - Sankar Prasad Rath
- Department of Chemistry
- Indian Institute of Technology Kanpur
- Kanpur 208016
- India
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