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Wang Z, Yu Q, Zhao Z, Zhang Y. Ferroheme/Ferriheme Directly Involved in the Synthesis and Decomposition of Hydrazine as an Electron Carrier during Anammox. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10140-10148. [PMID: 38781353 DOI: 10.1021/acs.est.3c08525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Anammox bacteria performed the reaction of NH4+ and NO with hydrazine synthase to produce N2H4, followed by the decomposition of N2H4 with hydrazine dehydrogenase to generate N2. Ferroheme/ferriheme, which serves as the active center of both hydrazine synthase and hydrazine dehydrogenase, is thought to play a crucial role in the synthesis and decomposition of N2H4 during Anammox due to its high redox activity. However, this has yet to be proven and the exact mechanisms by which ferroheme/ferriheme is involved in the Anammox process remain unclear. In this study, abiotic and biological assays confirmed that ferroheme participated in NH4+ and NO reactions to generate N2H4 and ferriheme, and the produced N2H4 reacted with ferriheme to generate N2 and ferroheme. In other words, the ferroheme/ferriheme cycle drove the continuous reaction between NH4+ and NO. Raman, ultraviolet-visible spectroscopy, and X-ray absorption fine structure spectroscopy confirmed that ferroheme/ferriheme is involved in the synthesis and decomposition of N2H4 via the core FeII/FeIII cycle. The mechanism of ferroheme/ferriheme participation in the synthesis and decomposition of N2H4 was proposed by density functional theory calculations. These findings revealed for the first time the heme electron transfer mechanisms, which are of great significance for deepening the understanding of Anammox.
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Affiliation(s)
- Zhenxin Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian116024, China
| | - Qilin Yu
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian116024, China
| | - Zhiqiang Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian116024, China
| | - Yaobin Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian116024, China
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2
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Flesch S, Domenianni LI, Vöhringer P. Primary processes of the archetypal model complex azido(porphinato)iron(III) from ultrafast vibrational-electronic spectroscopy. J Chem Phys 2024; 160:214310. [PMID: 38836452 DOI: 10.1063/5.0204617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Accepted: 05/17/2024] [Indexed: 06/06/2024] Open
Abstract
Azidoiron complexes serve as valuable photochemical precursors for catalytically active species containing high-valent iron. In bioinorganic chemistry, azido(tetraphenylporphinato)iron(III), i.e., [FeIII(tpp)(N3)] with tpp = 5, 10, 15, 20-tetraphenylporphyrin-21, 23-diido, constitutes the archetypal model system that was used to access for the first time the terminal nitridoiron core, FeV ≡ N, in the biomimetic redox-non-innocent ligand environment. So far, the light-induced dynamics leading to the oxidation of the metal and the release of dinitrogen from the N3-ligand have only been studied for precursors featuring redox-innocent auxiliary ligands that simplify the electronic structure change accompanying the photo-transformation. Here, we monitored the primary events of the above paradigmatic complex, following its optical excitation in the ultraviolet-to-visible spectral range using femtosecond spectroscopy with probing in both the UV-vis and mid-infrared regions. Following ultrafast Soret-excitation at 400 nm, the complex relaxes to the lowest excited sextet state by a first internal conversion in less than 200 fs. The excited state then undergoes vibrational relaxation on a time scale of roughly 2 ps before internally converting yet again to recover the sextet electronic ground state within 19.5 ps. Spectroscopic evidence is obtained neither for a transient occupation of the energetically lowest metal-centered state, 41A1, nor for vibrational relaxation in the ground-state. The primary processes seen here are thus in contrast to those previously derived from ultrafast UV-pump/vis-probe and UV-pump/XANES-probe spectroscopies for the halide congener [FeIII(tpp)(Cl)]. Any photochemical transformation of the complex arises from two-photon-induced dynamics.
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Affiliation(s)
- Stefan Flesch
- Clausius-Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Luis I Domenianni
- Clausius-Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
| | - Peter Vöhringer
- Clausius-Institut für Physikalische und Theoretische Chemie, Rheinische Friedrich-Wilhelms-Universität, Wegelerstraße 12, 53115 Bonn, Germany
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Paradisi A, Bellei M, Bortolotti CA, Di Rocco G, Ranieri A, Borsari M, Sola M, Battistuzzi G. Effects of removal of the axial methionine heme ligand on the binding of S. cerevisiae iso-1 cytochrome c to cardiolipin. J Inorg Biochem 2024; 252:112455. [PMID: 38141433 DOI: 10.1016/j.jinorgbio.2023.112455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/05/2023] [Accepted: 12/13/2023] [Indexed: 12/25/2023]
Abstract
The cleavage of the axial S(Met) - Fe bond in cytochrome c (cytc) upon binding to cardiolipin (CL), a glycerophospholipid of the inner mitochondrial membrane, is one of the key molecular changes that impart cytc with (lipo)peroxidase activity essential to its pro-apoptotic function. In this work, UV - VIS, CD, MCD and fluorescence spectroscopies were used to address the role of the Fe - M80 bond in controlling the cytc-CL interaction, by studying the binding of the Met80Ala (M80A) variant of S. cerevisiae iso-1 cytc (ycc) to CL liposomes in comparison with the wt protein [Paradisi et al. J. Biol. Inorg. Chem. 25 (2020) 467-487]. The results show that the integrity of the six-coordinate heme center along with the distal heme site containing the Met80 ligand is a not requisite for cytc binding to CL. Indeed, deletion of the Fe - S(Met80) bond has a little impact on the mechanism of ycc-CL interaction, although it results in an increased heme accessibility to solvent and a reduced structural stability of the protein. In particular, M80A features a slightly tighter binding to CL at low CL/cytc ratios compared to wt ycc, possibly due to the lift of some constraints to the insertion of the CL acyl chains into the protein hydrophobic core. M80A binding to CL maintains the dependence on the CL-to-cytc mixing scheme displayed by the wt species.
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Affiliation(s)
- Alessandro Paradisi
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Marzia Bellei
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Carlo Augusto Bortolotti
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Giulia Di Rocco
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Antonio Ranieri
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Marco Borsari
- Department of Chemistry and Geology, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Marco Sola
- Department of Life Sciences, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy
| | - Gianantonio Battistuzzi
- Department of Chemistry and Geology, University of Modena and Reggio Emilia, via Campi 103, 41126 Modena, Italy.
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Wolf S, Domes R, Domes C, Frosch T. Spectrally Resolved and Highly Parallelized Raman Difference Spectroscopy for the Analysis of Drug-Target Interactions between the Antimalarial Drug Chloroquine and Hematin. Anal Chem 2024; 96:3345-3353. [PMID: 38301154 PMCID: PMC10902819 DOI: 10.1021/acs.analchem.3c04231] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2024]
Abstract
Malaria is a severe disease caused by cytozoic parasites of the genus Plasmodium, which infiltrate and infect red blood cells. Several drugs have been developed to combat the devastating effects of malaria. Antimalarials based on quinolines inhibit the crystallization of hematin into hemozoin within the parasite, ultimately leading to its demise. Despite the frequent use of these agents, there are unanswered questions about their mechanisms of action. In the present study, the quinoline chloroquine and its interaction with the target structure hematin was investigated using an advanced, highly parallelized Raman difference spectroscopy (RDS) setup. Simultaneous recording of the spectra of hematin and chloroquine mixtures with varying compositions enabled the observation of changes in peak heights and positions based on the altered molecular structure resulting from their interaction. A shift of (-1.12 ± 0.05) cm-1 was observed in the core-size marker band ν(CαCm)asym peak position of the 1:1 chloroquine-hematin mixture compared to pure hematin. The oxidation-state marker band ν(pyrrole half-ring)sym exhibited a shift by (+0.93 ± 0.13) cm-1. These results were supported by density functional theory (DFT) calculations, indicating a hydrogen bond between the quinolinyl moiety of chloroquine and the oxygen atom of ferric protoporphyrin IX hydroxide (Fe(III)PPIX-OH). The consequence is a reduced electron density within the porphyrin moiety and an increase in its core size. This hypothesis provided further insights into the mechanism of hemozoin inhibition, suggesting chloroquine binding to the monomeric form of hematin, thereby preventing its further crystallization to hemozoin.
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Affiliation(s)
- Sebastian Wolf
- Leibniz Institute of Photonic Technology, 07745 Jena, Germany
| | - Robert Domes
- Leibniz Institute of Photonic Technology, 07745 Jena, Germany
| | - Christian Domes
- Leibniz Institute of Photonic Technology, 07745 Jena, Germany
| | - Torsten Frosch
- Biophotonics and Biomedical Engineering Group, Technical University Darmstadt, Merckstr. 25, 64283 Darmstadt, Germany
- Leibniz Institute of Photonic Technology, 07745 Jena, Germany
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Kosar N, Wajid S, Ayub K, Gilani MA, Binti Zainal Arfan NH, Sheikh Abdul Hamid MH, Imran M, Sheikh NS, Mahmood T. Giant NLO response and deep ultraviolet transparency of dual (alkali/alkaline earth) metals doped C 6O 6Li 6 electrides. Heliyon 2023; 9:e18264. [PMID: 37533989 PMCID: PMC10391932 DOI: 10.1016/j.heliyon.2023.e18264] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 07/07/2023] [Accepted: 07/12/2023] [Indexed: 08/04/2023] Open
Abstract
The designing of new materials having outstanding nonlinear optical (NLO) response is much needed for use in latest optics. Herein, the geometric, electronic and NLO properties of alkali and alkaline earth metals doped C6O6Li6 (alk-C6O6Li6-alkearth, alkearth = Ca, Mg, Be and alk = K, Na, Li) electrides is studied via quantum chemical approach. The interaction energies (Eint) are examined to illustrate their thermodynamic stability. The strong interaction energy of -39.99 kcal mol-1 is observed for Ca-C6O6Li6-Li electride in comparison to others. Frontier molecular orbitals (FMOs) energy gap of considered complexes is changed due to the electronic density shifting between metals and C6O6Li6 surface, which notifies the semi conducting properties of these electrides. The FMOs isodensities and natural bond orbital (NBO) charge analysis are performed to justify charge transfer between dopants and complexant. UV-Visible study also confirmed the application of these electrides as deep ultra-violet laser devices. NLO response is studied through calculation of first hyperpolarizability (βo). The highest βo value of 1.68 × 105 au is calculated for Mg-C6O6Li6-K electride. NLO response is further rationalized by three- and two-level models approach.
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Affiliation(s)
- Naveen Kosar
- Department of Chemistry, University of Management and Technology (UMT), C-11, Johar Town Lahore, Pakistan
| | - Sunaina Wajid
- Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad-22060, Pakistan
| | - Khurshid Ayub
- Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad-22060, Pakistan
| | - Mazhar Amjad Gilani
- Department of Chemistry, COMSATS University Islamabad, Lahore Campus, Lahore, Pakistan
| | - Nur Hazimah Binti Zainal Arfan
- Chemical Sciences, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam
| | | | - Muhammad Imran
- Department of Chemistry, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
| | - Nadeem S. Sheikh
- Chemical Sciences, Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam
| | - Tariq Mahmood
- Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Abbottabad-22060, Pakistan
- Department of Chemistry, College of Science, University of Bahrain, P.O. Box 32038, Bahrain
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6
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Johnson KL, Graves AB, Eckhert K, Liptak MD. Second-sphere tuning of analogues for the ferric-hydroperoxoheme form of Mycobacterium tuberculosis MhuD. J Inorg Biochem 2023; 246:112300. [PMID: 37364353 DOI: 10.1016/j.jinorgbio.2023.112300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 06/15/2023] [Accepted: 06/17/2023] [Indexed: 06/28/2023]
Abstract
Mycobacterium tuberculosis MhuD catalyzes the oxygenation of heme to mycobilin; experimental data presented here elucidates the novel hydroxylation reaction catalyzed by this enzyme. Analogues for the critical ferric-hydroperoxoheme (MhuD-heme-OOH) intermediate of this enzyme were characterized using UV/Vis absorption (Abs), circular dichroism (CD), and magnetic CD (MCD) spectroscopies. In order to extract electronic transition energies from these spectroscopic data, a novel global fitting model was developed for analysis of UV/Vis Abs, CD, and MCD data. A variant of MhuD was prepared, N7S, which weakens the affinity of heme-bound enzyme for a hydroperoxo analogue, azide, without significantly altering the protein secondary structure. Global fitting of spectroscopic data acquired in this study revealed that the second-sphere N7S substitution perturbs the electronic structure of two analogues for MhuD-heme-OOH: azide-inhibited MhuD (MhuD-heme-N3) and cyanide-inhibited MhuD (MhuD-heme-CN). The ground state electronic structures of MhuD-heme-N3 and MhuD-heme-CN were assessed using variable-temperature, variable-field MCD. Altogether, these data strongly suggest that there is a hydrogen bond between the Asn7 side-chain and the terminal oxygen of the hydroperoxo ligand in MhuD-heme-OOH. As discussed herein, this finding supports a novel hydroxylation reaction mechanism where the Asn7 side-chain guides a transient hydroxyl radical derived from homolysis of the OO bond in MhuD-heme-OOH to the β- or δ-meso carbon of the porphyrin ligand yielding β- or δ-meso-hydroxyheme, respectively.
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Affiliation(s)
- Kayla L Johnson
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America
| | - Amanda B Graves
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America
| | - Kaitlyn Eckhert
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America
| | - Matthew D Liptak
- Department of Chemistry, University of Vermont, 82 University Place, Burlington, VT 05405, United States of America.
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Harland JB, Samanta S, Lehnert N. Bacterial nitric oxide reductase (NorBC) models employing click chemistry. J Inorg Biochem 2023; 246:112280. [PMID: 37352656 DOI: 10.1016/j.jinorgbio.2023.112280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/15/2023] [Accepted: 05/30/2023] [Indexed: 06/25/2023]
Abstract
Bacterial NO Reductase (NorBC or cNOR) is a membrane-bound enzyme found in denitrifying bacteria that catalyzes the two-electron reduction of NO to N2O and water. The mechanism by which NorBC operates is highly debated, due to the fact that this enzyme is difficult to work with, and no intermediates of the NO reduction reaction could have been identified so far. The unique active site of NorBC consists of a heme b3/non-heme FeB diiron center. Synthetic model complexes provide the opportunity to obtain insight into possible mechanistic alternatives for this enzyme. In this paper, we present three new synthetic model systems for NorBC, consisting of a tetraphenylporphyrin-derivative clicked to modified BMPA-based ligands (BMPA = bis(methylpyridyl)amine) that model the non-heme site in the enzyme. These complexes have been characterized by EPR, IR and UV-Vis spectroscopy. The reactivity with NO was then investigated, and it was found that the complex with the BMPA-carboxylate ligand as the non-heme component has a very low affinity for NO at the non-heme iron site. If the carboxylate functional group is replaced with a phenolate or pyridine group, reactivity is restored and formation of a diiron dinitrosyl complex was observed. Upon one-electron reduction of the nitrosylated complexes, following the semireduced pathway for NO reduction, formation of dinitrosyl iron complexes (DNICs) was observed in all three cases, but no N2O could be detected.
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Affiliation(s)
- Jill B Harland
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Subhra Samanta
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Nicolai Lehnert
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States.
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Sonea A, Branch KL, Warren JJ. The Pattern of Hydroxyphenyl-Substitution Influences CO 2 Reduction More Strongly than the Number of Hydroxyphenyl Groups in Iron-Porphyrin Electrocatalysts. ACS Catal 2023. [DOI: 10.1021/acscatal.2c06275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Affiliation(s)
- Ana Sonea
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Kaitlin L. Branch
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
| | - Jeffrey J. Warren
- Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada
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Zheng J, Zhou D, Han J, Liu J, Cao R, Lei H, Bian H, Fang Y. Non-negligible Axial Ligand Effect on Electrocatalytic CO 2 Reduction with Iron Porphyrin Complexes. J Phys Chem Lett 2022; 13:11811-11817. [PMID: 36519945 DOI: 10.1021/acs.jpclett.2c03235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Iron(III) porphyrin complexes have been demonstrated as one of the efficient molecular catalysts for the electrochemical reduction of CO2. However, the role of axial ligands coordinated with a metal center in the complex on the electrochemical CO2 reduction activity has not been fully explored yet. Herein, iron(III) tetraphenylporphyrin thiocyanate (FeTPP-SCN) is synthesized from a commercially available catalyst of FeTPP-Cl by a counteranion exchanging reaction. Cyclic voltammetry measurements showed that the catalytic activity of FeTPP-SCN is noticeably suppressed in the DMF solutions. The structural dynamics of the axial ligand in FeTPP-SCN are further examined by the FTIR and ultrafast IR spectroscopies, where the SCN ligand is employed as the local vibrational probe. Vibrational relaxation measurements showed that the reorientational dynamics of SCN ligands was strongly restricted in DMF solution, suggesting that the subtle electrostatic interaction between the ligands and metal center in the complex can have a non-negligible effect on its catalytic activity.
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Affiliation(s)
- Jiancong Zheng
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Dexia Zhou
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Jinxiu Han
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Jing Liu
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Rui Cao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Haitao Lei
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Hongtao Bian
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
| | - Yu Fang
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China
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Di Rocco G, Ranieri A, Borsari M, Sola M, Bortolotti CA, Battistuzzi G. Assessing the Functional and Structural Stability of the Met80Ala Mutant of Cytochrome c in Dimethylsulfoxide. Molecules 2022; 27:molecules27175630. [PMID: 36080396 PMCID: PMC9458088 DOI: 10.3390/molecules27175630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/02/2022] Open
Abstract
The Met80Ala variant of yeast cytochrome c is known to possess electrocatalytic properties that are absent in the wild type form and that make it a promising candidate for biocatalysis and biosensing. The versatility of an enzyme is enhanced by the stability in mixed aqueous/organic solvents that would allow poorly water-soluble substrates to be targeted. In this work, we have evaluated the effect of dimethylsulfoxide (DMSO) on the functionality of the Met80Ala cytochrome c mutant, by investigating the thermodynamics and kinetics of electron transfer in mixed water/DMSO solutions up to 50% DMSO v/v. In parallel, we have monitored spectroscopically the retention of the main structural features in the same medium, focusing on both the overall protein structure and the heme center. We found that the organic solvent exerts only minor effects on the redox and structural properties of the mutant mostly as a result of the modification of the dielectric constant of the solvent. This would warrant proper functionality of this variant also under these potentially hostile experimental conditions, that differ from the physiological milieu of cytochrome c.
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Affiliation(s)
- Giulia Di Rocco
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Antonio Ranieri
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Marco Borsari
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Marco Sola
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
| | - Carlo Augusto Bortolotti
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
- Correspondence: (C.A.B.); (G.B.); Tel.: +39-0592058608 (C.A.B.); +39-059208639 (G.B.)
| | - Gianantonio Battistuzzi
- Department of Chemical and Geological Sciences, University of Modena and Reggio Emilia, Via Campi 103, 41125 Modena, Italy
- Correspondence: (C.A.B.); (G.B.); Tel.: +39-0592058608 (C.A.B.); +39-059208639 (G.B.)
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11
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Paul N, Sarkar R, Sarkar S. Iron and Zinc Porphyrin Linked MoO(dithiolene) Complexes in Relevance to Electron Transfer between Mo-cofactor and Cytochrome b5 in Sulfite Oxidase. Dalton Trans 2022; 51:12447-12452. [DOI: 10.1039/d2dt01863b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxo-molybdenum (dithiolene) complex covalently linked individually to iron and zinc porphyrin have been synthesized to show an electron transfer between the two metal centres in relevance to electron transfer from...
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12
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Zhao J, Qian F, Guo W, Li J, Lin Z. Linkage Isomers of 4-Methylimidazolate Mn(II) Porphyrinates: Hindered or Unhindered? Inorg Chem 2021; 60:7465-7474. [PMID: 33947188 DOI: 10.1021/acs.inorgchem.1c00755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Three different manganese(II) porphyrins have been exploited to react with 4-methylimidazolate (4-MeIm-), and the five-coordinate products are characterized by ultraviolet-visible, single-crystal X-ray, and electronic paramagnetic resonance spectroscopies. Interestingly, 4-MeIm- is found to bond to the metal center through either of the two N atoms (N1 or N3), which yielded two linkage isomers with either an unhindered or a hindered ligand conformation, respectively. Investigations revealed it is the large metal out-of-plane displacements (Δ24 and Δ4 ≥ 0.59 Å) that have rendered the equivalence of two isomers with a small energy difference (5.2-8.3 kJ/mol). The nonbonded intra- and intermolecular interactions thus become crucial factors in the balance of linkage isomerization. All of the products in both solution and solid states show the same characteristic resonances of high-spin Mn(II) (S = 5/2) with g⊥ ≈ 5.9 and g∥ ≈ 2.0 at 4 K, consistent with the weak effects of the axial ligand on core conformation and metal electronic configurations. Zero-field splitting parameters obtained through simulations are also reported.
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Affiliation(s)
- Jianping Zhao
- College of Materials Science and Optoelectronic Technology, CAS Center for Excellence in Topological Quantum Computation, and Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Fei Qian
- State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
| | - Wenping Guo
- National Energy Center for Coal to Liquids, Synfuels China Company, Ltd., Beijing 101400, China
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology, CAS Center for Excellence in Topological Quantum Computation, and Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Zeyuan Lin
- The University of Chinese Academy of Sciences, Beijing 100049, China
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13
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Galinato MGI, Brocious EP, Paulat F, Martin S, Skodack J, Harland JB, Lehnert N. Elucidating the Electronic Structure of High-Spin [MnIII(TPP)Cl] Using Magnetic Circular Dichroism Spectroscopy. Inorg Chem 2020; 59:2144-2162. [DOI: 10.1021/acs.inorgchem.9b02599] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mary Grace I. Galinato
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
- School of Science-Chemistry, Penn State Behrend, Erie, Pennsylvania 16563, United States
| | - Emily P. Brocious
- School of Science-Chemistry, Penn State Behrend, Erie, Pennsylvania 16563, United States
| | - Florian Paulat
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Sherri Martin
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Joshua Skodack
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jill B. Harland
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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14
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Paradisi A, Lancellotti L, Borsari M, Bellei M, Bortolotti CA, Di Rocco G, Ranieri A, Sola M, Battistuzzi G. Met80 and Tyr67 affect the chemical unfolding of yeast cytochrome c: comparing the solution vs.immobilized state. RSC Chem Biol 2020. [DOI: 10.1039/d0cb00115e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The motional regime affects the unfolding propensity and axial heme coordination of the Met80Ala and Met80Ala/Tyr67Ala variants of yeast iso-1 cytochromec.
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Affiliation(s)
| | - Lidia Lancellotti
- Department of Chemistry and Geology
- University of Modena and Reggio Emilia
- 41126 Modena
- Italy
| | - Marco Borsari
- Department of Chemistry and Geology
- University of Modena and Reggio Emilia
- 41126 Modena
- Italy
| | - Marzia Bellei
- Department of Life Sciences
- University of Modena and Reggio Emilia
- 41126 Modena
- Italy
| | | | - Giulia Di Rocco
- Department of Life Sciences
- University of Modena and Reggio Emilia
- 41126 Modena
- Italy
| | - Antonio Ranieri
- Department of Life Sciences
- University of Modena and Reggio Emilia
- 41126 Modena
- Italy
| | - Marco Sola
- Department of Life Sciences
- University of Modena and Reggio Emilia
- 41126 Modena
- Italy
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15
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Plugis NM, Rudd ND, Krzystek J, Swenson DC, Telser J, Larrabee JA. Cobalt(II) "Scorpionate" complexes as electronic ground state models for cobalt-substituted zinc enzymes: Structure investigation by magnetic circular dichroism. J Inorg Biochem 2019; 203:110876. [PMID: 31756558 DOI: 10.1016/j.jinorgbio.2019.110876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/19/2019] [Accepted: 10/01/2019] [Indexed: 12/15/2022]
Abstract
Zinc centers in pseudo-tetrahedral geometry are widely found in biology, often with three histidine ligands from protein. The trispyrazolylborate "scorpionate" ligand is used as a model for this tris(histidine) motif, and spectroscopically active CoII is often used as a substitute for spectroscopically silent ZnII. In this work, four pseudo-tetrahedral scorpionate complexes with the formula (Tpt-Bu,Tn)CoL, where Tpt-Bu,Tn = hydrotris(3-tert-butyl, 5-2'-thienyl-pyrazol-1-yl)borate anion and L = Cl-, N3-, NCO-, or NCS-, were studied using variable-temperature, variable-field magnetic circular dichroism (VTVH MCD) spectroscopy. The major goal was to determine the axial and rhombic zero field splitting (ZFS) parameters (D and E, respectively) of these S = 3/2 systems and compare these ZFS parameters to those determined previously by high-frequency and -field electron paramagnetic resonance (HFEPR) spectroscopy on the same (L = Cl- and NCS-) or closely related complexes. Additionally, HFEPR studies were undertaken here on the complexes with L = N3-, NCO-. Crystal structures for these two complexes are also first reported here. The values of D determined by VTVH MCD were + 12.8 and + 3.6 cm-1 for the L = Cl- and NCS- complexes, respectively. These values are in close agreement with those for the same complexes as previously determined by HFEPR. The values of D determined by VTVH MCD were + 3.0 and + 6.6 cm-1 for the L = N3- and NCO- complexes, respectively. These values were not as close to those determined by HFEPR in the present study, which are 4.2 cm-1 ≤ |D| ≤ 5.6 cm-1 in Tpt-Bu,TnCoN3, and 8.3 cm-1 ≤ |D| ≤ 11.0 cm-1 in Tpt-Bu,TnCoNCO. The bands in MCD spectra of these complexes were assigned in C3v symmetry and a complete ligand-field analysis of the MCD data was made using the Angular Overlap Model (AOM), which is compared to previous results.
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Affiliation(s)
- Nicholas M Plugis
- Department of Chemistry & Biochemistry, 547 Bicentennial Way, Middlebury College, Middlebury, VT 05753, USA
| | - Nathan D Rudd
- Department of Chemistry & Biochemistry, 547 Bicentennial Way, Middlebury College, Middlebury, VT 05753, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310, USA
| | - Dale C Swenson
- Department of Chemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Joshua Telser
- Department of Biological, Physical and Health Sciences, Roosevelt University, 430 South Michigan Avenue, Chicago, IL 60605, USA
| | - James A Larrabee
- Department of Chemistry & Biochemistry, 547 Bicentennial Way, Middlebury College, Middlebury, VT 05753, USA.
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16
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Manesis AC, Musselman BW, Keegan BC, Shearer J, Lehnert N, Shafaat HS. A Biochemical Nickel(I) State Supports Nucleophilic Alkyl Addition: A Roadmap for Methyl Reactivity in Acetyl Coenzyme A Synthase. Inorg Chem 2019; 58:8969-8982. [PMID: 30788970 PMCID: PMC6635881 DOI: 10.1021/acs.inorgchem.8b03546] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
![]()
Nickel-containing
enzymes such as methyl coenzyme M reductase (MCR) and carbon monoxide
dehydrogenase/acetyl coenzyme A synthase (CODH/ACS) play a critical
role in global energy conversion reactions, with significant contributions
to carbon-centered processes. These enzymes are implied to cycle through
a series of nickel-based organometallic intermediates during catalysis,
though identification of these intermediates remains challenging.
In this work, we have developed and characterized a nickel-containing
metalloprotein that models the methyl-bound organometallic intermediates
proposed in the native enzymes. Using a nickel(I)-substituted azurin
mutant, we demonstrate that alkyl binding occurs via nucleophilic
addition of methyl iodide as a methyl donor. The paramagnetic NiIII-CH3 species initially generated can be rapidly
reduced to a high-spin NiII-CH3 species in the
presence of exogenous reducing agent, following a reaction sequence
analogous to that proposed for ACS. These two distinct bioorganometallic
species have been characterized by optical, EPR, XAS, and MCD spectroscopy,
and the overall mechanism describing methyl reactivity with nickel
azurin has been quantitatively modeled using global kinetic simulations.
A comparison between the nickel azurin protein system and existing
ACS model compounds is presented. NiIII-CH3 Az
is only the second example of two-electron addition of methyl iodide
to a NiI center to give an isolable species and the first
to be formed in a biologically relevant system. These results highlight
the divergent reactivity of nickel across the two intermediates, with
implications for likely reaction mechanisms and catalytically relevant
states in the native ACS enzyme. A bioorganometallic model
for acetyl coenzyme A synthase has been developed. This model protein
is able to bind a cationic methyl group via direct addition to the
nickel(I) center. The resultant nickel(III)-methyl species has been
characterized via optical and electron paramagnetic resonance spectroscopy,
and the reduced nickel(II)-methyl state has been characterized using
magnetic circular dichroism and X-ray spectroscopy. Implications for
further reactivity with CO are gleaned from electronic structure analysis
of the nickel-methyl species.
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Affiliation(s)
- Anastasia C Manesis
- Department of Chemistry and Biochemistry , The Ohio State University , 100 W. 18th Avenue , Columbus , Ohio 43210 , United States
| | - Bradley W Musselman
- Department of Chemistry , University of Michigan , 930 N. University Avenue , Ann Arbor , Michigan 48109 , United States
| | - Brenna C Keegan
- Department of Chemistry , Trinity University , One Trinity Place , San Antonio , Texas 78212 , United States
| | - Jason Shearer
- Department of Chemistry , Trinity University , One Trinity Place , San Antonio , Texas 78212 , United States
| | - Nicolai Lehnert
- Department of Chemistry , University of Michigan , 930 N. University Avenue , Ann Arbor , Michigan 48109 , United States
| | - Hannah S Shafaat
- Department of Chemistry and Biochemistry , The Ohio State University , 100 W. 18th Avenue , Columbus , Ohio 43210 , United States
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17
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Abdullin D, Fleck N, Klein C, Brehm P, Spicher S, Lützen A, Grimme S, Schiemann O. Synthesis of μ
2
‐Oxo‐Bridged Iron(III) Tetraphenylporphyrin–Spacer–Nitroxide Dimers and their Structural and Dynamics Characterization by using EPR and MD Simulations. Chemistry 2019; 25:2586-2596. [DOI: 10.1002/chem.201805016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 11/13/2018] [Indexed: 11/08/2022]
Affiliation(s)
- Dinar Abdullin
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Nico Fleck
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Christoph Klein
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
- Kekulé Institute of Organic Chemistry and Biochemistry Gerhard-Domagk-Str. 1 53121 Bonn Germany
| | - Philipp Brehm
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Sebastian Spicher
- Mulliken Center for Theoretical ChemistryUniversity of Bonn Beringstr. 4 53115 Bonn Germany
| | - Arne Lützen
- Kekulé Institute of Organic Chemistry and Biochemistry Gerhard-Domagk-Str. 1 53121 Bonn Germany
| | - Stefan Grimme
- Mulliken Center for Theoretical ChemistryUniversity of Bonn Beringstr. 4 53115 Bonn Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
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18
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McQuarters AB, Blaesi EJ, Kampf JW, Alp EE, Zhao J, Hu M, Krebs C, Lehnert N. Synthetic Model Complex of the Key Intermediate in Cytochrome P450 Nitric Oxide Reductase. Inorg Chem 2019; 58:1398-1413. [PMID: 30623648 DOI: 10.1021/acs.inorgchem.8b02947] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Fungal denitrification plays a crucial role in the nitrogen cycle and contributes to the total N2O emission from agricultural soils. Here, cytochrome P450 NO reductase (P450nor) reduces two NO to N2O using a single heme site. Despite much research, the exact nature of the critical "Intermediate I" responsible for the key N-N coupling step in P450nor is unknown. This species likely corresponds to a Fe-NHOH-type intermediate with an unknown electronic structure. Here we report a new strategy to generate a model system for this intermediate, starting from the iron(III) methylhydroxylamide complex [Fe(3,5-Me-BAFP)(NHOMe)] (1), which was fully characterized by 1H NMR, UV-vis, electron paramagnetic resonance, and vibrational spectroscopy (rRaman and NRVS). Our data show that 1 is a high-spin ferric complex with an N-bound hydroxylamide ligand that is strongly coordinated (Fe-N distance, 1.918 Å; Fe-NHOMe stretch, 558 cm-1). Simple one-electron oxidation of 1 at -80 °C then cleanly generates the first model system for Intermediate I, [Fe(3,5-Me-BAFP)(NHOMe)]+ (1+). UV-vis, resonance Raman, and Mössbauer spectroscopies, in comparison to the chloro analogue [Fe(3,5-Me-BAFP)(Cl)]+, demonstrate that 1+ is best described as an FeIII-(NHOMe)• complex with a bound NHOMe radical. Further reactivity studies show that 1+ is highly reactive toward NO, a reaction that likely proceeds via N-N bond formation, following a radical-radical-type coupling mechanism. Our results therefore provide experimental evidence, for the first time, that an FeIII-(NHOMe)• electronic structure is indeed a reasonable electronic description for Intermediate I and that this electronic structure is advantageous for P450nor catalysis because it can greatly facilitate N-N bond formation and, ultimately, N2O generation.
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Affiliation(s)
- Ashley B McQuarters
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Elizabeth J Blaesi
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Jeff W Kampf
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - E Ercan Alp
- Advanced Photon Source (APS) , Argonne National Laboratory (ANL) , Argonne , Illinois 60439 , United States
| | - Jiyong Zhao
- Advanced Photon Source (APS) , Argonne National Laboratory (ANL) , Argonne , Illinois 60439 , United States
| | - Michael Hu
- Advanced Photon Source (APS) , Argonne National Laboratory (ANL) , Argonne , Illinois 60439 , United States
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
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19
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Heit YN, Sergentu DC, Autschbach J. Magnetic circular dichroism spectra of transition metal complexes calculated from restricted active space wavefunctions. Phys Chem Chem Phys 2019; 21:5586-5597. [DOI: 10.1039/c8cp07849a] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Multiconfigurational restricted active space (RAS) self-consistent field (SCF) or configuration interaction (CI) approaches, augmented with a treatment of spin–orbit coupling by state interaction, were used to calculate the magnetic circular dichroism , , and/or for closed- and open-shell transition metal complexes.
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Affiliation(s)
- Yonaton N. Heit
- Department of Chemistry
- University at Buffalo, State University of New York
- Buffalo
- USA
| | | | - Jochen Autschbach
- Department of Chemistry
- University at Buffalo, State University of New York
- Buffalo
- USA
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20
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Wolf MW, Rizzolo K, Elliott SJ, Lehnert N. Resonance Raman, Electron Paramagnetic Resonance, and Magnetic Circular Dichroism Spectroscopic Investigation of Diheme Cytochrome c Peroxidases from Nitrosomonas europaea and Shewanella oneidensis. Biochemistry 2018; 57:6416-6433. [PMID: 30335984 DOI: 10.1021/acs.biochem.8b00732] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome c peroxidases (bCcPs) are diheme enzymes required for the reduction of H2O2 to water in bacteria. There are two classes of bCcPs: one is active in the diferric form (constitutively active), and the other requires the reduction of the high-potential heme (H-heme) before catalysis commences (reductively activated) at the low-potential heme (L-heme). To improve our understanding of the mechanisms and heme electronic structures of these different bCcPs, a constitutively active bCcP from Nitrosomonas europaea ( NeCcP) and a reductively activated bCcP from Shewanella oneidensis ( SoCcP) were characterized in both the diferric and semireduced states by electron paramagnetic resonance (EPR), resonance Raman (rRaman), and magnetic circular dichroism (MCD) spectroscopy. In contrast to some previous crystallographic studies, EPR and rRaman spectra do not indicate the presence of significant amounts of a five-coordinate, high-spin ferric heme in NeCcP or SoCcP in either the diferric or semireduced state in solution. This observation points toward a mechanism of activation in which the active site L-heme is not in a static, five-coordinate state but where the activation is more subtle and likely involves formation of a six-coordinate hydroxo complex, which could then react with hydrogen peroxide in an acid-base-type reaction to create Compound 0, the ferric hydroperoxo complex. This mechanism lies in stark contrast to the diheme enzyme MauG that exhibits a static, five-coordinate open heme site at the peroxidatic heme and that forms a more stable FeIV═O intermediate.
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Affiliation(s)
- Matthew W Wolf
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Kimberly Rizzolo
- Department of Chemistry , Boston University , 590 Commonwealth Avenue , Boston , Massachusetts 02215 , United States
| | - Sean J Elliott
- Department of Chemistry , Boston University , 590 Commonwealth Avenue , Boston , Massachusetts 02215 , United States
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
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21
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Koebke KJ, Ruckthong L, Meagher JL, Mathieu E, Harland J, Deb A, Lehnert N, Policar C, Tard C, Penner-Hahn JE, Stuckey JA, Pecoraro VL. Clarifying the Copper Coordination Environment in a de Novo Designed Red Copper Protein. Inorg Chem 2018; 57:12291-12302. [PMID: 30226758 PMCID: PMC6183058 DOI: 10.1021/acs.inorgchem.8b01989] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cupredoxins are copper-dependent electron-transfer proteins that can be categorized as blue, purple, green, and red depending on the spectroscopic properties of the Cu(II) bound forms. Interestingly, despite significantly different first coordination spheres and nuclearity, all cupredoxins share a common Greek Key β-sheet fold. We have previously reported the design of a red copper protein within a completely distinct three-helical bundle protein, α3DChC2. (1) While this design demonstrated that a β-barrel fold was not requisite to recapitulate the properties of a native cupredoxin center, the parent peptide α3D was not sufficiently stable to allow further study through additional mutations. Here we present the design of an elongated protein GRANDα3D (GRα3D) with Δ Gu = -11.4 kcal/mol compared to the original design's -5.1 kcal/mol. Diffraction quality crystals were grown of GRα3D (a first for an α3D peptide) and solved to a resolution of 1.34 Å. Examination of this structure suggested that Glu41 might interact with the Cu in our previously reported red copper protein. The previous bis(histidine)(cysteine) site (GRα3DChC2) was designed into this new scaffold and a series of variant constructs were made to explore this hypothesis. Mutation studies around Glu41 not only prove the proposed interaction, but also enabled tuning of the constructs' hyperfine coupling constant from 160 to 127 × 10-4 cm-1. X-ray absorption spectroscopy analysis is consistent with these hyperfine coupling differences being the result of variant 4p mixing related to coordination geometry changes. These studies not only prove that an Glu41-Cu interaction leads to the α3DChC2 construct's red copper protein like spectral properties, but also exemplify the exact control one can have in a de novo construct to tune the properties of an electron-transfer Cu site.
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Affiliation(s)
- Karl J. Koebke
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Leela Ruckthong
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jennifer L. Meagher
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Emilie Mathieu
- Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Jill Harland
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aniruddha Deb
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Clotilde Policar
- Laboratoire des biomolécules, LBM, Département de chimie, École normale supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France
| | - Cédric Tard
- LCM, CNRS, Ecole Polytechnique, Université Paris-Saclay, 91128 Palaiseau Cedex, France
| | - James E. Penner-Hahn
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jeanne A. Stuckey
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Vincent L. Pecoraro
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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22
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Speelman AL, White CJ, Zhang B, Alp EE, Zhao J, Hu M, Krebs C, Penner-Hahn J, Lehnert N. Non-heme High-Spin {FeNO} 6-8 Complexes: One Ligand Platform Can Do It All. J Am Chem Soc 2018; 140:11341-11359. [PMID: 30107126 DOI: 10.1021/jacs.8b06095] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heme and non-heme iron-nitrosyl complexes are important intermediates in biology. While there are numerous examples of low-spin heme iron-nitrosyl complexes in different oxidation states, much less is known about high-spin (hs) non-heme iron-nitrosyls in oxidation states other than the formally ferrous NO adducts ({FeNO}7 in the Enemark-Feltham notation). In this study, we present a complete series of hs-{FeNO}6-8 complexes using the TMG3tren coligand. Redox transformations from the hs-{FeNO}7 complex [Fe(TMG3tren)(NO)]2+ to its {FeNO}6 and {FeNO}8 analogs do not alter the coordination environment of the iron center, allowing for detailed comparisons between these species. Here, we present new MCD, NRVS, XANES/EXAFS, and Mössbauer data, demonstrating that these redox transformations are metal based, which allows us to access hs-Fe(II)-NO-, Fe(III)-NO-, and Fe(IV)-NO- complexes. Vibrational data, analyzed by NCA, directly quantify changes in Fe-NO bonding along this series. Optical data allow for the identification of a "spectator" charge-transfer transition that, together with Mössbauer and XAS data, directly monitors the electronic changes of the Fe center. Using EXAFS, we are also able to provide structural data for all complexes. The magnetic properties of the complexes are further analyzed (from magnetic Mössbauer). The properties of our hs-{FeNO}6-8 complexes are then contrasted to corresponding, low-spin iron-nitrosyl complexes where redox transformations are generally NO centered. The hs-{FeNO}8 complex can further be protonated by weak acids, and the product of this reaction is characterized. Taken together, these results provide unprecedented insight into the properties of biologically relevant non-heme iron-nitrosyl complexes in three relevant oxidation states.
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Affiliation(s)
- Amy L Speelman
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Corey J White
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Bo Zhang
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - E Ercan Alp
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Jiyong Zhao
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Michael Hu
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Carsten Krebs
- Department of Chemistry and Department of Biochemistry and Molecular Biology , The Pennsylvania State University , University Park , Pennsylvania 16802 , United States
| | - James Penner-Hahn
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics , University of Michigan , Ann Arbor , Michigan 48109-1055 , United States
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23
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Arbelo-López HD, Rodriguez-Mackenzie AD, Roman-Morales EM, Wymore T, López-Garriga J. Charge Transfer and π to π* Transitions in the Visible Spectra of Sulfheme Met Isomeric Structures. J Phys Chem B 2018; 122:4947-4955. [PMID: 29689164 DOI: 10.1021/acs.jpcb.7b12393] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Since the 1863 discovery of a new green hemoglobin derivative called "sulfhemoglobin", the nature of the characteristic 618 nm absorption band has been the subject of several hypotheses. The experimental spectra are a function of the observation time and interplay between two major sulfheme isomer concentrations (a three- and five-membered ring adduct), with the latter being the dominant isomer at longer times. Thus, time-dependent density functional theory (TDDFT) was used to calculate the sulfheme excited states and visualize the highest occupied molecular orbitals (HOMOs) and lowest unoccupied MOs (LUMOs) of both isomers in order to interpret the transitions between them. These two isomers have distinguishable a1u and a2u HOMO energies. Formation of the three-membered ring SA isomeric structure decreases the energy of the HOMO a1u and a2u orbitals compared to the unmodified heme due to the electron-withdrawing, sulfur-containing, three-membered ring. Conversely, formation of the SC isomeric structure decreases the energy of the HOMO a1u and a2u orbitals due to the electron-withdrawing, sulfur-containing, five-membered ring. The calculations reveal that the absorption spectrum within the 700 nm region arises from a mixture of MOs but can be characterized as π to π* transitions, while the 600 nm region is characterized by π to dπ (d yz, d xz) transitions having components of a deoxy-like derivative.
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Affiliation(s)
- Hector D Arbelo-López
- Chemistry Department , University of Puerto Rico Mayagüez Campus , Mayagüez , Puerto Rico
| | | | - Elddie M Roman-Morales
- Chemistry Department , University of Puerto Rico Mayagüez Campus , Mayagüez , Puerto Rico
| | - Troy Wymore
- Chemistry Department , University of Michigan , Ann Arbor , Michigan , United States
| | - Juan López-Garriga
- Chemistry Department , University of Puerto Rico Mayagüez Campus , Mayagüez , Puerto Rico
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24
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Tebo AG, Pinter TBJ, García-Serres R, Speelman AL, Tard C, Sénéque O, Blondin G, Latour JM, Penner-Hahn J, Lehnert N, Pecoraro VL. Development of a Rubredoxin-Type Center Embedded in a de Dovo-Designed Three-Helix Bundle. Biochemistry 2018; 57:2308-2316. [PMID: 29561598 DOI: 10.1021/acs.biochem.8b00091] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Protein design is a powerful tool for interrogating the basic requirements for the function of a metal site in a way that allows for the selective incorporation of elements that are important for function. Rubredoxins are small electron transfer proteins with a reduction potential centered near 0 mV (vs normal hydrogen electrode). All previous attempts to design a rubredoxin site have focused on incorporating the canonical CXXC motifs in addition to reproducing the peptide fold or using flexible loop regions to define the morphology of the site. We have produced a rubredoxin site in an utterly different fold, a three-helix bundle. The spectra of this construct mimic the ultraviolet-visible, Mössbauer, electron paramagnetic resonance, and magnetic circular dichroism spectra of native rubredoxin. Furthermore, the measured reduction potential suggests that this rubredoxin analogue could function similarly. Thus, we have shown that an α-helical scaffold sustains a rubredoxin site that can cycle with the desired potential between the Fe(II) and Fe(III) states and reproduces the spectroscopic characteristics of this electron transport protein without requiring the classic rubredoxin protein fold.
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Affiliation(s)
- Alison G Tebo
- Program in Chemical Biology , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Tyler B J Pinter
- Department of Chemistry and Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Ricardo García-Serres
- Université Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249), F-38054 Grenoble , France
| | - Amy L Speelman
- Department of Chemistry and Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Cédric Tard
- LCM, CNRS, École Polytechnique, Université Paris-Saclay, 91128 Palaiseau Cedex, France
| | - Olivier Sénéque
- Université Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249), F-38054 Grenoble , France
| | - Geneviève Blondin
- Université Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249), F-38054 Grenoble , France
| | - Jean-Marc Latour
- Université Grenoble Alpes, CNRS, CEA, BIG, LCBM (UMR 5249), F-38054 Grenoble , France
| | - James Penner-Hahn
- Department of Chemistry and Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Nicolai Lehnert
- Department of Chemistry and Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
| | - Vincent L Pecoraro
- Program in Chemical Biology , University of Michigan , Ann Arbor , Michigan 48109 , United States.,Department of Chemistry and Biophysics , University of Michigan , Ann Arbor , Michigan 48109 , United States
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25
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Ryland ES, Lin MF, Verkamp MA, Zhang K, Benke K, Carlson M, Vura-Weis J. Tabletop Femtosecond M-edge X-ray Absorption Near-Edge Structure of FeTPPCl: Metalloporphyrin Photophysics from the Perspective of the Metal. J Am Chem Soc 2018. [DOI: 10.1021/jacs.8b01101] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- Elizabeth S. Ryland
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Ming-Fu Lin
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Max A. Verkamp
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Kaili Zhang
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Kristopher Benke
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Michaela Carlson
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Josh Vura-Weis
- Department of Chemistry, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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26
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Römelt C, Ye S, Bill E, Weyhermüller T, van Gastel M, Neese F. Electronic Structure and Spin Multiplicity of Iron Tetraphenylporphyrins in Their Reduced States as Determined by a Combination of Resonance Raman Spectroscopy and Quantum Chemistry. Inorg Chem 2018; 57:2141-2148. [PMID: 29384663 DOI: 10.1021/acs.inorgchem.7b03018] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron tetraphenylporphyrins are prime candidates as catalysts for CO2 reduction. Yet, even after 40 years of research, fundamental questions about the electronic structure of their reduced states remain, in particular as to whether the reducing equivalents are stored at the iron center or at the porphyrin ligand. In this contribution, we address this question by a combination of resonance Raman spectroscopy and quantum chemistry. Analysis of the data allows for an unequivocal identification of the porphyrin as the redox active moiety. Additionally, determination of the spin state of iron is possible by comparing the characteristic shifts of spin and oxidation-state-sensitive marker bands in the Raman spectrum with calculations of planar porphyrin model structures.
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Affiliation(s)
- Christina Römelt
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Shengfa Ye
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Eckhard Bill
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Thomas Weyhermüller
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Maurice van Gastel
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max Planck Institute for Chemical Energy Conversion , Stiftstrasse 34-36, 45470 Mülheim an der Ruhr, Germany
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27
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Bellei M, Bortolotti CA, Di Rocco G, Borsari M, Lancellotti L, Ranieri A, Sola M, Battistuzzi G. The influence of the Cys46/Cys55 disulfide bond on the redox and spectroscopic properties of human neuroglobin. J Inorg Biochem 2018; 178:70-86. [DOI: 10.1016/j.jinorgbio.2017.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/21/2017] [Accepted: 10/09/2017] [Indexed: 12/21/2022]
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28
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Monte-Pérez I, Kundu S, Chandra A, Craigo KE, Chernev P, Kuhlmann U, Dau H, Hildebrandt P, Greco C, Van Stappen C, Lehnert N, Ray K. Temperature Dependence of the Catalytic Two- versus Four-Electron Reduction of Dioxygen by a Hexanuclear Cobalt Complex. J Am Chem Soc 2017; 139:15033-15042. [DOI: 10.1021/jacs.7b07127] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Inés Monte-Pérez
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
| | - Subrata Kundu
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
| | - Anirban Chandra
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
| | - Kathryn E. Craigo
- Department
of Chemistry, The University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Petko Chernev
- Freie Universität Berlin, FB Physik, Arnimallee 14, D-14195 Berlin, Germany
| | - Uwe Kuhlmann
- Department
of Chemistry, Technische Universität Berlin, Straße des
17. Juni 135, 10623 Berlin, Germany
| | - Holger Dau
- Freie Universität Berlin, FB Physik, Arnimallee 14, D-14195 Berlin, Germany
| | - Peter Hildebrandt
- Department
of Chemistry, Technische Universität Berlin, Straße des
17. Juni 135, 10623 Berlin, Germany
| | - Claudio Greco
- Department
of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza
della Scienza, 1, 20126 Milan, Italy
| | - Casey Van Stappen
- Department
of Chemistry, The University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Nicolai Lehnert
- Department
of Chemistry, The University of Michigan, 930 N. University Ave., Ann Arbor, Michigan 48109, United States
| | - Kallol Ray
- Humboldt-Universität zu Berlin, Institut für Chemie, Brook-Taylor-Straße 2, D-12489 Berlin, Germany
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29
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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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30
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Fujisawa K, Soma S, Kurihara H, Dong HT, Bilodeau M, Lehnert N. A cobalt–nitrosyl complex with a hindered hydrotris(pyrazolyl)borate coligand: detailed electronic structure, and reactivity towards dioxygen. Dalton Trans 2017; 46:13273-13289. [DOI: 10.1039/c7dt01565h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The cobalt–nitrosyl complex [Co(NO)(L3)] is supported by a highly hindered tridentate nitrogen ligand, hydrotris(3-tertiary butyl-5-isopropyl-1-pyrazolyl)borate (denoted as L3−), and shows a linear Co–N–O unit.
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Affiliation(s)
| | - Shoko Soma
- Department of Chemistry
- Ibaraki University
- Mito 310-8512
- Japan
| | | | - Hai T. Dong
- Department of Chemistry and Department of Biophysics
- University of Michigan
- Ann Arbor
- USA
| | - Max Bilodeau
- Department of Chemistry and Department of Biophysics
- University of Michigan
- Ann Arbor
- USA
| | - Nicolai Lehnert
- Department of Chemistry and Department of Biophysics
- University of Michigan
- Ann Arbor
- USA
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31
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Gendron F, Fleischauer VE, Duignan TJ, Scott BL, Löble MW, Cary SK, Kozimor SA, Bolvin H, Neidig ML, Autschbach J. Magnetic circular dichroism of UCl6− in the ligand-to-metal charge-transfer spectral region. Phys Chem Chem Phys 2017. [DOI: 10.1039/c7cp02572f] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We present a combined ab initio theoretical and experimental study of the magnetic circular dichroism (MCD) spectrum of the octahedral UCl6− complex ion in the UV-Vis spectral region.
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Affiliation(s)
- Frédéric Gendron
- Department of Chemistry
- University at Buffalo
- State University of New York
- Buffalo
- USA
| | | | - Thomas J. Duignan
- Department of Chemistry
- University at Buffalo
- State University of New York
- Buffalo
- USA
| | - Brian L. Scott
- Los Alamos National Laboratory
- Los Alamos
- New Mexico 87544
- USA
| | | | | | | | - Hélène Bolvin
- Laboratoire de Chimie et de Physique Quantiques
- 31062 Toulouse
- France
| | | | - Jochen Autschbach
- Department of Chemistry
- University at Buffalo
- State University of New York
- Buffalo
- USA
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32
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Ye S, Kupper C, Meyer S, Andris E, Navrátil R, Krahe O, Mondal B, Atanasov M, Bill E, Roithová J, Meyer F, Neese F. Magnetic Circular Dichroism Evidence for an Unusual Electronic Structure of a Tetracarbene-Oxoiron(IV) Complex. J Am Chem Soc 2016; 138:14312-14325. [PMID: 27682505 DOI: 10.1021/jacs.6b07708] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In biology, high valent oxo-iron(IV) species have been shown to be pivotal intermediates for functionalization of C-H bonds in the catalytic cycles of a range of O2-activating iron enzymes. This work details an electronic-structure investigation of [FeIV(O)(LNHC)(NCMe)]2+ (LNHC = 3,9,14,20-tetraaza-1,6,12,17-tetraazoniapenta-cyclohexacosane-1(23),4,6(26),10,12(25),15,17(24),21-octaene, complex 1) using helium tagging infrared photodissociation (IRPD), absorption, and magnetic circular dichroism (MCD) spectroscopy, coupled with DFT and highly correlated wave function based multireference calculations. The IRPD spectrum of complex 1 reveals the Fe-O stretching vibration at 832 ± 3 cm-1. By analyzing the Franck-Condon progression, we can determine the same vibration occurring at 616 ± 10 cm-1 in the E(dxy → dxz,yz) excited state. Both values are similar to those measured for [FeIV(O)(TMC)(NCMe)]2+ (TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane). The low-temperature MCD spectra of complex 1 exhibit three pseudo A-term signals around 12 500, 17 000, and 24 300 cm-1. We can unequivocally assign them to the ligand field transitions of dxy → dxz,yz, dxz,yz → dz2, and dxz,yz → dx2-y2, respectively, through direct calculations of MCD spectra and independent determination of the MCD C-term signs from the corresponding electron donating and accepting orbitals. In comparison with the corresponding transitions observed for [FeIV(O) (SR-TPA)(NCMe)]2+ (SR-TPA = tris(3,5-dimethyl-4-methoxypyridyl-2-methy)amine), the excitations within the (FeO)2+ core of complex 1 have similar transition energies, whereas the excitation energy for dxz,yz → dx2-y2 is significantly higher (∼12 000 cm-1 for [FeIV(O)(SR-TPA)(NCMe)]2+). Our results thus substantiate that the tetracarbene ligand (LNHC) of complex 1 does not significantly affect the bonding in the (FeO)2+ unit but strongly destabilizes the dx2-y2 orbital to eventually lift it above dz2. As a consequence, this unusual electron configuration leads to an unprecedentedly larger quintet-triplet energy separation for complex 1, which largely rules out the possibility that the H atom transfer reaction may take place on the quintet surface and hence quenches two-state reactivity. The resulting mechanistic implications are discussed.
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Affiliation(s)
- Shengfa Ye
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Claudia Kupper
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen , Tammannstr. 4, D-37077 Göttingen, Germany
| | - Steffen Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen , Tammannstr. 4, D-37077 Göttingen, Germany
| | - Erik Andris
- Department of Organic Chemistry, Faculty of Science, Charles University in Prague , Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Rafael Navrátil
- Department of Organic Chemistry, Faculty of Science, Charles University in Prague , Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Oliver Krahe
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Bhaskar Mondal
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Mihail Atanasov
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany.,Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences , 1113 Sofia, Bulgaria
| | - Eckhard Bill
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Jana Roithová
- Department of Organic Chemistry, Faculty of Science, Charles University in Prague , Hlavova 8, 128 43 Praha 2, Czech Republic
| | - Franc Meyer
- Institut für Anorganische Chemie, Georg-August-Universität Göttingen , Tammannstr. 4, D-37077 Göttingen, Germany
| | - Frank Neese
- Max-Planck Institut für Chemische Energiekonversion, Stiftstr. 34-36, D-45470 Mülheim an der Ruhr, Germany
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33
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McQuarters AB, Speelman AL, Chen L, Elmore BO, Fan W, Feng C, Lehnert N. Exploring second coordination sphere effects in nitric oxide synthase. J Biol Inorg Chem 2016; 21:997-1008. [PMID: 27686338 DOI: 10.1007/s00775-016-1396-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 09/15/2016] [Indexed: 11/28/2022]
Abstract
Second coordination sphere (SCS) effects in proteins are modulated by active site residues and include hydrogen bonding, electrostatic/dipole interactions, steric interactions, and π-stacking of aromatic residues. In Cyt P450s, extended H-bonding networks are located around the proximal cysteinate ligand of the heme, referred to as the 'Cys pocket'. These hydrogen bonding networks are generally believed to regulate the Fe-S interaction. Previous work identified the S(Cys) → Fe σ CT transition in the high-spin (hs) ferric form of Cyt P450cam and corresponding Cys pocket mutants by low-temperature (LT) MCD spectroscopy [Biochemistry 50:1053, 2011]. In this work, we have investigated the effect of the hydrogen bond from W409 to the axial Cys ligand of the heme in the hs ferric state (with H4B and L-Arg bound) of rat neuronal nitric oxide synthase oxygenase construct (nNOSoxy) using MCD spectroscopy. For this purpose, wt enzyme and W409 mutants were investigated where the H-bonding network with the axial Cys ligand is perturbed. Overall, the results are similar to Cyt P450cam and show the intense S(Cys) → Fe σ CT band in the LT MCD spectrum at about 27,800 cm-1, indicating that this feature is a hallmark of {heme-thiolate} active sites. The discovery of this MCD feature could constitute a new approach to classify {heme-thiolate} sites in hs ferric proteins. Finally, the W409 mutants show that the hydrogen bond from this group only has a small effect on the Fe-S(Cys) bond strength, at least in the hs ferric form of the protein studied here. Low-temperature MCD spectroscopy is used to investigate the effect of the hydrogen bond from W409 to the axial Cys ligand of the heme in neuronal nitric oxide synthase. The intense S(Cys) → Fe σ-CT band is monitored to identify changes in the Fe-S(Cys) bond in wild-type protein and W409 mutants.
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Affiliation(s)
- Ashley B McQuarters
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Amy L Speelman
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA.,Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Li Chen
- College of Pharmacy, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Bradley O Elmore
- College of Pharmacy, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Weihong Fan
- College of Pharmacy, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Changjian Feng
- College of Pharmacy, University of New Mexico, Albuquerque, NM, 87131, USA
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA. .,Department of Biophysics, University of Michigan, Ann Arbor, MI, 48109, USA.
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34
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Colmer HE, Margarit CG, Smith JM, Jackson TA, Telser J. Spectroscopic and Computational Investigation of Low-Spin Mn(III) Bis(scorpionate) Complexes. Eur J Inorg Chem 2016; 2016:2413-2423. [PMID: 28713219 PMCID: PMC5507630 DOI: 10.1002/ejic.201501250] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Indexed: 11/06/2022]
Abstract
Six-coordinate MnIII complexes are typically high-spin (S = 2), however, the scorpionate ligand, both in its traditional, hydridotris(pyrazolyl)borate form, Tp- and Tp*- (the latter with 3,5-dimethylpyrazole substituents) and in an aryltris(carbene)borate (i.e., N-heterocyclic carbene, NHC) form, [Ph(MeIm)3B]-, (MeIm = 3-methylimidazole) lead to formation of bis(scorpionate) complexes of MnIII with spin triplet ground states; three of which were investigated herein: [Tp2Mn]SbF6 (1SBF6), [Tp*2Mn]SbF6 (2SBF6), and [{Ph(MeIm)3B}2Mn]CF3SO3 (3CF3SO3). These trigonally symmetric complexes were studied experimentally by magnetic circular dichroism (MCD) spectroscopy (the propensity of 3 to oxidize to MnIV precluded collection of useful MCD data) including variable temperatures and fields (VTVH-MCD) and computationally by ab initio CASSCF/NEVPT2 methods. These combined experimental and theoretical techniques establish the 3A2g electronic ground state for the three complexes, and provide information on the energy of the "conventional" high-spin excited state (5Eg) and other, triplet excited states. These results show the electronic effect of pyrazole ring substituents in comparing 1 and 2. The tunability of the scorpionate ligand, even by perhaps the simplest change (from pyrazole in 1 to 3,5-dimethylpyrazole in 2) is quantitatively manifested through perturbations in ligand-field excited-state energies that impact ground-state zero-field splittings. The comparison with the NHC donor is much more dramatic. In 3, the stronger σ-donor properties of the NHC lead to a quantitatively different electronic structure, so that the lowest lying spin triplet excited state, 3Eg, is much closer in energy to the ground state than in 1 or 2. The zero-field splitting (zfs) parameters of the three complexes were calculated and in the case of 1 and 2 compare closely to experiment (lower by < 10%, < 2 cm-1 in absolute terms); for 3 the large magnitude zfs is reproduced, although there is ambiguity about its sign. The comprehensive picture obtained for these bis(scorpionate) MnIII complexes provides quantitative insight into the role played by the scorpionate ligand in stabilizing unusual electronic structures.
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Affiliation(s)
- Hannah E Colmer
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045 USA
| | - Charles G Margarit
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003 USA
| | - Jeremy M Smith
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico 88003 USA
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405 USA
| | - Timothy A Jackson
- Department of Chemistry, University of Kansas, Lawrence, Kansas 66045 USA
| | - Joshua Telser
- Department of Biological, Chemical and Physical Sciences, Roosevelt University, Chicago, Illinois 60605 USA
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35
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Graves AB, Graves MT, Liptak MD. Measurement of Heme Ruffling Changes in MhuD Using UV–vis Spectroscopy. J Phys Chem B 2016; 120:3844-53. [DOI: 10.1021/acs.jpcb.6b01497] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Amanda B. Graves
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, United States
| | - Max T. Graves
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, United States
| | - Matthew D. Liptak
- Department of Chemistry, University of Vermont, Burlington, Vermont 05405, United States
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36
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Starus A, Nocek B, Bennett B, Larrabee JA, Shaw DL, Sae-Lee W, Russo MT, Gillner DM, Makowska-Grzyska M, Joachimiak A, Holz RC. Inhibition of the dapE-Encoded N-Succinyl-L,L-diaminopimelic Acid Desuccinylase from Neisseria meningitidis by L-Captopril. Biochemistry 2015; 54:4834-44. [PMID: 26186504 DOI: 10.1021/acs.biochem.5b00475] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Binding of the competitive inhibitor L-captopril to the dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase from Neisseria meningitidis (NmDapE) was examined by kinetic, spectroscopic, and crystallographic methods. L-Captopril, an angiotensin-converting enzyme (ACE) inhibitor, was previously shown to be a potent inhibitor of the DapE from Haemophilus influenzae (HiDapE) with an IC50 of 3.3 μM and a measured Ki of 1.8 μM and displayed a dose-responsive antibiotic activity toward Escherichia coli. L-Captopril is also a competitive inhibitor of NmDapE with a Ki of 2.8 μM. To examine the nature of the interaction of L-captopril with the dinuclear active site of DapE, we have obtained electron paramagnetic resonance (EPR) and magnetic circular dichroism (MCD) data for the enzymatically hyperactive Co(II)-substituted forms of both HiDapE and NmDapE. EPR and MCD data indicate that the two Co(II) ions in DapE are antiferromagnetically coupled, yielding an S = 0 ground state, and suggest a thiolate bridge between the two metal ions. Verification of a thiolate-bridged dinuclear complex was obtained by determining the three-dimensional X-ray crystal structure of NmDapE in complex with L-captopril at 1.8 Å resolution. Combination of these data provides new insights into binding of L-captopril to the active site of DapE enzymes as well as important inhibitor-active site residue interaction's. Such information is critical for the design of new, potent inhibitors of DapE enzymes.
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Affiliation(s)
- Anna Starus
- †Department of Chemistry and Biochemistry, Loyola University-Chicago, 1068 West Sheridan Road, Chicago, Illinois 60626, United States
| | - Boguslaw Nocek
- ‡Center for Structural Genomics of Infectious Diseases, Computation Institute, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Brian Bennett
- §Department of Physics, Marquette University, Milwaukee, Wisconsin 53201, United States
| | - James A Larrabee
- ∥Department of Chemistry and Biochemistry, Middlebury College, Middlebury, Vermont 05753, United States
| | - Daniel L Shaw
- ∥Department of Chemistry and Biochemistry, Middlebury College, Middlebury, Vermont 05753, United States
| | - Wisath Sae-Lee
- ∥Department of Chemistry and Biochemistry, Middlebury College, Middlebury, Vermont 05753, United States
| | - Marie T Russo
- ∥Department of Chemistry and Biochemistry, Middlebury College, Middlebury, Vermont 05753, United States
| | - Danuta M Gillner
- ⊥Department of Chemistry, Silesian University of Technology, 44-100 Gliwice, Poland
| | - Magdalena Makowska-Grzyska
- ‡Center for Structural Genomics of Infectious Diseases, Computation Institute, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Andrzej Joachimiak
- ‡Center for Structural Genomics of Infectious Diseases, Computation Institute, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, United States
| | - Richard C Holz
- #Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201, United States
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37
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Ye S, Xue G, Krivokapic I, Petrenko T, Bill E, Que Jr L, Neese F. Magnetic circular dichroism and computational study of mononuclear and dinuclear iron(IV) complexes. Chem Sci 2015; 6:2909-2921. [PMID: 26417426 PMCID: PMC4583211 DOI: 10.1039/c4sc03268c] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 02/26/2015] [Indexed: 12/13/2022] Open
Abstract
High-valent iron(IV)-oxo species are key intermediates in the catalytic cycles of a range of O2-activating iron enzymes. This work presents a detailed study of the electronic structures of mononuclear ([FeIV(O)(L)(NCMe)]2+, 1, L = tris(3,5-dimethyl-4-methoxylpyridyl-2-methyl)amine) and dinuclear ([(L)FeIV(O)(μ-O)FeIV(OH)(L)]3+, 2) iron(IV) complexes using absorption (ABS), magnetic circular dichroism (MCD) spectroscopy and wave-function-based quantum chemical calculations. For complex 1, the experimental MCD spectra at 2-10 K are dominated by a broad positive C-term band between 12000 and 18000 cm-1. As the temperature increases up to ~20 K, this feature is gradually replaced by a derivative-shaped signal. The computed MCD spectra are in excellent agreement with experiment, which reproduce not only the excitation energies and the MCD signs of key transitions but also their temperature-dependent intensity variations. To further corroborate the assignments suggested by the calculations, the individual MCD sign for each transition is independently determined from the corresponding electron donating and accepting orbitals. Thus, unambiguous assignments can be made for the observed transitions in 1. The ABS/MCD data of complex 2 exhibit ten features that are assigned as ligand-field transitions or oxo- or hydroxo-to-metal charge transfer bands, based on MCD/ABS intensity ratios, calculated excitation energies, polarizations, and MCD signs. In comparison with complex 1, the electronic structure of the FeIV=O site is not significantly perturbed by the binding to another iron(IV) center. This may explain the experimental finding that complexes 1 and 2 have similar reactivities toward C-H bond activation and O-atom transfer.
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Affiliation(s)
- Shengfa Ye
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Genqiang Xue
- Department of Chemistry , Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , USA .
| | - Itana Krivokapic
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Taras Petrenko
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Eckhard Bill
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
| | - Lawrence Que Jr
- Department of Chemistry , Center for Metals in Biocatalysis , University of Minnesota , 207 Pleasant St. SE , Minneapolis , Minnesota 55455 , USA .
| | - Frank Neese
- Max-Planck Institut für Chemische Energiekonversion , Stiftstraße 34-36 , D-45470 Mülheim an der Ruhr , Germany . ; ;
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38
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Rury AS, Wiley TE, Sension RJ. Energy cascades, excited state dynamics, and photochemistry in cob(III)alamins and ferric porphyrins. Acc Chem Res 2015; 48:860-7. [PMID: 25741574 DOI: 10.1021/ar5004016] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Porphyrins and the related chlorins and corrins contain a cyclic tetrapyrrole with the ability to coordinate an active metal center and to perform a variety of functions exploiting the oxidation state, reactivity, and axial ligation of the metal center. These compounds are used in optically activated applications ranging from light harvesting and energy conversion to medical therapeutics and photodynamic therapy to molecular electronics, spintronics, optoelectronic thin films, and optomagnetics. Cobalt containing corrin rings extend the range of applications through photolytic cleavage of a unique axial carbon-cobalt bond, permitting spatiotemporal control of drug delivery. The photochemistry and photophysics of cyclic tetrapyrroles are controlled by electronic relaxation dynamics including internal conversion and intersystem crossing. Typically the electronic excitation cascades through ring centered ππ* states, ligand to metal charge transfer (LMCT) states, metal to ligand charge transfer (MLCT) states, and metal centered states. Ultrafast transient absorption spectroscopy provides a powerful tool for the investigation of the electronic state dynamics in metal containing tetrapyrroles. The UV-visible spectrum is sensitive to the oxidation state, electronic configuration, spin state, and axial ligation of the central metal atom. Ultrashort broadband white light probes spanning the range from 270 to 800 nm, combined with tunable excitation pulses, permit the detailed unravelling of the time scales involved in the electronic energy cascade. State-of-the-art theoretical calculations provide additional insight required for precise assignment of the states. In this Account, we focus on recent ultrafast transient absorption studies of ferric porphyrins and corrin containing cob(III)alamins elucidating the electronic states responsible for ultrafast energy cascades, excited state dynamics, and the resulting photoreactivity or photostability of these compounds. Iron tetraphenyl porphyrin chloride (Fe((III))TPPCl) exhibits picosecond decay to a metal centered d → d* (4)T state. This state decays on a ca. 16 ps time scale in room temperature solution but persists for much longer in a cryogenic glass. The photoreactivity of the (4)T state may lead to novel future applications for these compounds. In contrast, the nonplanar cob(III)alamins contain two axial ligands to the central cobalt atom. The upper axial ligand can be an alkyl group as in the two biologically active coenzymes or a nonalkyl ligand such as -CN in cyanocobalamin (vitamin B12) or -OH in hydroxocobalamin. The electronic structure, energy cascade, and bond cleavage of these compounds is sensitive to the details of the axial ligand. Nonalkylcobalamins exhibit ultrafast internal conversion to a low-lying state of metal to ligand or ligand to metal charge transfer character. The compounds are generally photostable with ground state recovery complete on a time scale of 2-7 ps in room temperature aqueous solution. Alkylcobalamins exhibit ultrafast internal conversion to an S1 state of d/π → π* character. Most compounds undergo bond cleavage from this state with near unit quantum yield within ∼100 ps. Recent theoretical calculations provide a potential energy surface accounting for these observations. Conformation dependent mixing of the corrin π and cobalt d orbitals plays a significant role in the observed photochemistry and photophysics.
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Affiliation(s)
- Aaron S. Rury
- Department of Chemistry and
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Theodore E. Wiley
- Department of Chemistry and
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Roseanne J. Sension
- Department of Chemistry and
Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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39
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Zheng RH, Wei WM, Zhu LL, Shi Q. Theoretical study of the resonance Raman spectra for meso-tetrakis(3,5-di-tertiarybutylphenyl)-porphyrin. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 133:707-713. [PMID: 24996212 DOI: 10.1016/j.saa.2014.06.047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 05/26/2014] [Accepted: 06/03/2014] [Indexed: 06/03/2023]
Abstract
Applying time-dependent density functional theory (TDDFT), we study the resonance Raman spectra for the Q and B bands of the meso-tetrakis(3,5-di-tertiarybutylphenyl)-porphyrin (H2TBPP) molecule including both Raman A term (Franck-Condon term) and Raman B term (Herzberg-Teller term) contributions. It is found that Raman B term can be one order of magnitude larger than Raman A term and dominates resonance Raman for the Q band resonance. In comparison with the recent experimental Raman spectra of H2TBPP with incident light frequency 532nm, we predict the absence of 1580cm(-1) band in the resonance Raman spectra which agrees well with the experimental results, whereas the previous theoretical calculation using non-resonance strategy failed to do so.
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Affiliation(s)
- Ren-hui Zheng
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, People's Republic of China.
| | - Wen-mei Wei
- Department of Chemistry, College of Basic Medicine, Anhui Medical University, Hefei, Anhui 230032, People's Republic of China
| | - Li-li Zhu
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, People's Republic of China
| | - Qiang Shi
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, People's Republic of China
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40
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Karunakaran V, Sun Y, Benabbas A, Champion PM. Investigations of the low frequency modes of ferric cytochrome c using vibrational coherence spectroscopy. J Phys Chem B 2014; 118:6062-70. [PMID: 24823442 PMCID: PMC4059251 DOI: 10.1021/jp501298c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Femtosecond vibrational coherence
spectroscopy is used to investigate
the low frequency vibrational dynamics of the electron transfer heme
protein, cytochrome c (cyt c). The
vibrational coherence spectra of ferric cyt c have
been measured as a function of excitation wavelength within the Soret
band. Vibrational coherence spectra obtained with excitation between
412 and 421 nm display a strong mode at ∼44 cm–1 that has been assigned to have a significant contribution from heme
ruffling motion in the electronic ground state. This assignment is
based partially on the presence of a large heme ruffling distortion
in the normal coordinate structural decomposition (NSD) analysis of
the X-ray crystal structures. When the excitation wavelength is moved
into the ∼421–435 nm region, the transient absorption
increases along with the relative intensity of two modes near ∼55
and 30 cm–1. The intensity of the mode near 44 cm–1 appears to minimize in this region and then recover
(but with an opposite phase compared to the blue excitation) when
the laser is tuned to 443 nm. These observations are consistent with
the superposition of both ground and excited state coherence in the
421–435 nm region due to the excitation of a weak porphyrin-to-iron
charge transfer (CT) state, which has a lifetime long enough to observe
vibrational coherence. The mode near 55 cm–1 is
suggested to arise from ruffling in a transient CT state that has
a less ruffled heme due to its iron d6 configuration.
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Affiliation(s)
- Venugopal Karunakaran
- Department of Physics and Center for Interdisciplinary Research on Complex Systems, Northeastern University , Boston, Massachusetts 02115, United States
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41
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Sakow D, Baabe D, Böker B, Burghaus O, Funk M, Kleeberg C, Menzel D, Pietzonka C, Bröring M. Iron 10-Thiacorroles: Bioinspired Iron(III) Complexes with an Intermediate Spin (S=3/2) Ground State. Chemistry 2014; 20:2913-24. [DOI: 10.1002/chem.201303786] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 10/17/2013] [Indexed: 11/07/2022]
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42
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Blusch LK, Craigo KE, Martin-Diaconescu V, McQuarters AB, Bill E, Dechert S, DeBeer S, Lehnert N, Meyer F. Hidden Non-Innocence in an Expanded Porphyrin: Electronic Structure of the Siamese-Twin Porphyrin’s Dicopper Complex in Different Oxidation States. J Am Chem Soc 2013; 135:13892-9. [DOI: 10.1021/ja406176e] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lina K. Blusch
- Institut für
Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen, Germany
| | - Kathryn E. Craigo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Vlad Martin-Diaconescu
- MPI für Chemische Energiekonversion, Stiftstraße
34-36, 45470 Mülheim
an der Ruhr, Germany
| | - Ashley B. McQuarters
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eckhard Bill
- MPI für Chemische Energiekonversion, Stiftstraße
34-36, 45470 Mülheim
an der Ruhr, Germany
| | - Sebastian Dechert
- Institut für
Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen, Germany
| | - Serena DeBeer
- MPI für Chemische Energiekonversion, Stiftstraße
34-36, 45470 Mülheim
an der Ruhr, Germany
- Department of
Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Nicolai Lehnert
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Franc Meyer
- Institut für
Anorganische Chemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen, Germany
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43
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Rury AS, Sension RJ. Broadband ultrafast transient absorption of iron (III) tetraphenylporphyrin chloride in the condensed phase. Chem Phys 2013. [DOI: 10.1016/j.chemphys.2013.01.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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44
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Westphal A, Klinkebiel A, Berends HM, Broda H, Kurz P, Tuczek F. Electronic Structure and Spectroscopic Properties of Mononuclear Manganese(III) Schiff Base Complexes: A Systematic Study on [Mn(acen)X] Complexes by EPR, UV/vis, and MCD Spectroscopy (X = Hal, NCS). Inorg Chem 2013; 52:2372-87. [DOI: 10.1021/ic301889e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Anne Westphal
- Institut
für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Arne Klinkebiel
- Institut
für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Hans-Martin Berends
- Institut
für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Henning Broda
- Institut
für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Philipp Kurz
- Institut
für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Felix Tuczek
- Institut
für Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
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45
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Daumann LJ, Comba P, Larrabee JA, Schenk G, Stranger R, Cavigliasso G, Gahan LR. Synthesis, Magnetic Properties, and Phosphoesterase Activity of Dinuclear Cobalt(II) Complexes. Inorg Chem 2013; 52:2029-43. [DOI: 10.1021/ic302418x] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Lena J. Daumann
- School of
Chemistry and Molecular Biosciences, The University of Queensland, Brisbane QLD 4072, Australia
| | - Peter Comba
- Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld
270, 69120 Heidelberg, Germany
| | - James A. Larrabee
- Department of Chemistry and Biochemistry, Middlebury College, Middlebury, Vermont 05753, United States
| | - Gerhard Schenk
- School of
Chemistry and Molecular Biosciences, The University of Queensland, Brisbane QLD 4072, Australia
- Department of Chemistry, National University of Ireland—Maynooth, Maynooth,
Co. Kildare, Ireland
| | - Robert Stranger
- Research School of Chemistry, Australian National University, Canberra 0200, Australia
| | - German Cavigliasso
- Research School of Chemistry, Australian National University, Canberra 0200, Australia
| | - Lawrence R. Gahan
- School of
Chemistry and Molecular Biosciences, The University of Queensland, Brisbane QLD 4072, Australia
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46
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Kuter D, Venter GA, Naidoo KJ, Egan TJ. Experimental and time-dependent density functional theory characterization of the UV-visible spectra of monomeric and μ-oxo dimeric ferriprotoporphyrin IX. Inorg Chem 2012; 51:10233-50. [PMID: 22963249 DOI: 10.1021/ic301154e] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Speciation of ferriprotoporphyrin IX, Fe(III)PPIX, in aqueous solution is complex. Despite the use of its characteristic spectroscopic features for identification, the theoretical basis of the unique UV-visible absorbance spectrum of μ-[Fe(III)PPIX](2)O has not been explored. To investigate this and to establish a structural and spectroscopic model for Fe(III)PPIX species, density functional theory (DFT) calculations were undertaken for H(2)O-Fe(III)PPIX and μ-[Fe(III)PPIX](2)O. The models agreed with related Fe(III)porphyrin crystal structures and reproduced vibrational spectra well. The UV-visible absorbance spectra of H(2)O-Fe(III)PPIX and μ-[Fe(III)PPIX](2)O were calculated using time-dependent DFT and reproduced major features of the experimental spectra of both. Transitions contributing to calculated excitations have been identified. The features of the electronic spectrum calculated for μ-[Fe(III)PPIX](2)O were attributed to delocalization of electron density between the two porphyrin rings of the dimer, the weaker ligand field of the axial ligand, and antiferromagnetic coupling of the Fe(III) centers. Room temperature magnetic circular dichroism (MCD) spectra have been recorded and are shown to be useful in distinguishing between these two Fe(III)PPIX species. Bands underlying major spectroscopic features were identified through simultaneous deconvolution of UV-visible and MCD spectra. Computed UV-visible spectra were compared to deconvoluted spectra. Interpretation of the prominent bands of H(2)O-Fe(III)PPIX largely conforms to previous literature. Owing to the weak paramagnetism of μ-[Fe(III)PPIX](2)O at room temperature and the larger number of underlying excitations, interpretation of its experimental UV-visible spectrum was necessarily tentative. Nonetheless, comparison with the calculated spectra of antiferromagnetically coupled and paramagnetic forms of the μ-oxo dimer of Fe(III)porphine suggested that the composition of the Soret band involves a mixture of π→π* and π→d(π) charge transfer transitions. The Q-band and charge transfer bands appear to amalgamate into a mixed low energy envelope consisting of excitations with heavily admixed π→π* and charge transfer transitions.
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Affiliation(s)
- David Kuter
- Department of Chemistry, Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701 South Africa
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47
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Rury AS, Goodrich LE, Galinato MGI, Lehnert N, Sension RJ. Ligand Recruitment and Spin Transitions in the Solid-State Photochemistry of Fe(III)TPPCl. J Phys Chem A 2012; 116:8321-33. [DOI: 10.1021/jp304667t] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Aaron S. Rury
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109,
United States
- Department
of Chemistry, University of Michigan, Ann
Arbor, Michigan 48109,
United States
| | - Lauren E. Goodrich
- Department
of Chemistry, University of Michigan, Ann
Arbor, Michigan 48109,
United States
| | - Mary Grace I. Galinato
- School of Science, Penn State Erie, The Behrend College, Erie, Pennsylvania
16563, United States
| | - Nicolai Lehnert
- Department
of Chemistry, University of Michigan, Ann
Arbor, Michigan 48109,
United States
| | - Roseanne J. Sension
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109,
United States
- Department
of Chemistry, University of Michigan, Ann
Arbor, Michigan 48109,
United States
- Department
of Physics, University of Michigan, Ann
Arbor, Michigan 48109,
United States
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48
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Battistuzzi G, Bortolotti CA, Bellei M, Di Rocco G, Salewski J, Hildebrandt P, Sola M. Role of Met80 and Tyr67 in the Low-pH Conformational Equilibria of Cytochrome c. Biochemistry 2012; 51:5967-78. [DOI: 10.1021/bi3007302] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gianantonio Battistuzzi
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Carlo Augusto Bortolotti
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Marzia Bellei
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Giulia Di Rocco
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
| | - Johannes Salewski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC14, Straße
des 17. Juni 135, D-10623 Berlin, Germany
| | - Marco Sola
- Department
of Chemistry, University of Modena and Reggio Emilia, via Campi 183,
41100 Modena, Italy
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49
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Gopakumar TG, Tang H, Morillo J, Berndt R. Transfer of Cl Ligands between Adsorbed Iron Tetraphenylporphyrin Molecules. J Am Chem Soc 2012; 134:11844-7. [DOI: 10.1021/ja302589z] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Thiruvancheril G. Gopakumar
- Institut für Experimentelle
und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
| | - Hao Tang
- CEMES/CNRS, 29, rue Jeanne
Marvig, B.P. 94347, 31055 Toulouse Cedex, France
- Universite de Toulouse, UPS, 31055 Toulouse, France
| | - Joseph Morillo
- CEMES/CNRS, 29, rue Jeanne
Marvig, B.P. 94347, 31055 Toulouse Cedex, France
- Universite de Toulouse, UPS, 31055 Toulouse, France
| | - Richard Berndt
- Institut für Experimentelle
und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany
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50
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Westphal A, Broda H, Kurz P, Neese F, Tuczek F. Magnetic Circular Dichroism Spectrum of the Molybdenum(V) Complex [Mo(O)Cl3dppe]: C-Term Signs and Intensities for Multideterminant Excited Doublet States. Inorg Chem 2012; 51:5748-63. [DOI: 10.1021/ic300201t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anne Westphal
- Institut für
Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Henning Broda
- Institut für
Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Philipp Kurz
- Institut für
Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
| | - Frank Neese
- Max-Planck-Institut für Bioanorganische Chemie, D-45470 Mülheim
an der Ruhr, Germany
| | - Felix Tuczek
- Institut für
Anorganische Chemie, Christian-Albrechts-Universität zu Kiel, D-24118 Kiel, Germany
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