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Aroule O, Jarraya M, Zins EL, Hochlaf M. Probing microhydration-induced effects on carbonyl compounds. Phys Chem Chem Phys 2024; 26:22230-22239. [PMID: 39129488 DOI: 10.1039/d4cp01035c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/13/2024]
Abstract
Characterizing the microhydration of organic molecules is a crucial step in understanding many phenomena relevant to atmospheric, biological, and industrial applications. However, its precise experimental and theoretical description remains a challenge. For four organic solutes containing a CO bond, and included in the recent HyDRA challenge [T. L. Fischer, M. Bödecker, A. Zehnacker-Rentien, R. A. Mata and M. A. Suhm, Phys. Chem. Chem. Phys., 2022, 24, 11442-11454.], we performed a detailed study of different monohydrate isomers and their properties; these were cyclooctanone (CON), 1,3-dimethyl-2-imidazolidinon (DMI), methyl lactate (MLA), and 2,2,2-trifluoroacetophenone (TPH) molecules. As reported in the literature, the O-H elongation shift of the water molecule appears to be a good candidate for characterizing complexation-induced effects. We also show that CO elongation shift and UV-vis spectroscopy can be successfully used for these purposes. Besides, we present a comparative analysis of the strengths of non-covalent interactions within these monohydrated complexes based on interpretative tools of quantum chemistry, including topological analysis of electron density (ρ), topological analysis of electron pairing function, and analysis of the core-valence bifurcation index (CVBI), which exhibits a close linear dependency on ρ. Accordingly, a classification of intermolecular water-solute interactions is proposed.
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Affiliation(s)
- Olivier Aroule
- MONARIS UMR 8233 CNRS, Sorbonne Université, 4 place Jussieu, 75252 Paris Cedex 5, France.
| | - Mahmoud Jarraya
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes 77454, Champs sur Marne, France.
| | - Emilie-Laure Zins
- MONARIS UMR 8233 CNRS, Sorbonne Université, 4 place Jussieu, 75252 Paris Cedex 5, France.
| | - Majdi Hochlaf
- Université Gustave Eiffel, COSYS/IMSE, 5 Bd Descartes 77454, Champs sur Marne, France.
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2
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Costa GJ, Liang R. Understanding the Multifaceted Mechanism of Compound I Formation in Unspecific Peroxygenases through Multiscale Simulations. J Phys Chem B 2023; 127:8809-8824. [PMID: 37796883 DOI: 10.1021/acs.jpcb.3c04589] [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: 10/07/2023]
Abstract
Unspecific peroxygenases (UPOs) can selectively oxyfunctionalize unactivated hydrocarbons by using peroxides under mild conditions. They circumvent the oxygen dilemma faced by cytochrome P450s and exhibit greater stability than the latter. As such, they hold great potential for industrial applications. A thorough understanding of their catalysis is needed to improve their catalytic performance. However, it remains elusive how UPOs effectively convert peroxide to Compound I (CpdI), the principal oxidizing intermediate in the catalytic cycle. Previous computational studies of this process primarily focused on heme peroxidases and P450s, which have significant differences in the active site from UPOs. Additionally, the roles of peroxide unbinding in the kinetics of CpdI formation, which is essential for interpreting existing experiments, have been understudied. Moreover, there has been a lack of free energy characterizations with explicit sampling of protein and hydration dynamics, which is critical for understanding the thermodynamics of the proton transport (PT) events involved in CpdI formation. To bridge these gaps, we employed multiscale simulations to comprehensively characterize the CpdI formation in wild-type UPO from Agrocybe aegerita (AaeUPO). Extensive free energy and potential energy calculations were performed in a quantum mechanics/molecular mechanics setting. Our results indicate that substrate-binding dehydrates the active site, impeding the PT from H2O2 to a nearby catalytic base (Glu196). Furthermore, the PT is coupled with considerable hydrogen bond network rearrangements near the active site, facilitating subsequent O-O bond cleavage. Finally, large unbinding free energy barriers kinetically stabilize H2O2 at the active site. These findings reveal a delicate balance among PT, hydration dynamics, hydrogen bond rearrangement, and cosubstrate unbinding, which collectively enable efficient CpdI formation. Our simulation results are consistent with kinetic measurements and offer new insights into the CpdI formation mechanism at atomic-level details, which can potentially aid the design of next-generation biocatalysts for sustainable chemical transformations of feedstocks.
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Affiliation(s)
- Gustavo J Costa
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - Ruibin Liang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
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3
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Aboelnga MM. Mechanistic insights into the chemistry of compound I formation in heme peroxidases: quantum chemical investigations of cytochrome c peroxidase. RSC Adv 2022; 12:15543-15554. [PMID: 35685178 PMCID: PMC9125774 DOI: 10.1039/d2ra01073a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/17/2022] [Indexed: 11/21/2022] Open
Abstract
Peroxidases are heme containing enzymes that catalyze peroxide-dependant oxidation of a variety of substrates through forming key ferryl intermediates, compounds I and II. Cytochrome c peroxidase (Ccp1) has served for decades as a chemical model toward understanding the chemical biology of this heme family of enzymes. It is known to feature a distinctive electronic behaviour for its compound I despite significant structural similarity to other peroxidases. A water-assisted mechanism has been proposed over a dry one for the formation of compound I in similar peroxidases. To better identify the viability of these mechanisms, we employed quantum chemistry calculations for the heme pocket of Ccp1 in three different spin states. We provided comparative energetic and structural results for the six possible pathways that suggest the preference of the dry mechanism energetically and structurally. The doublet state is found to be the most preferable spin state for the mechanism to proceed and for the formation of the Cpd I ferryl-intermediate irrespective of the considered dielectric constant used to represent the solvent environment. The nature of the spin state has negligible effects on the calculated structures but great impact on the energetics. Our analysis was also expanded to explain the major contribution of key residues to the peroxidase activity of Ccp1 through exploring the mechanism at various in silico generated Ccp1 variants. Overall, we provide valuable findings toward solving the current ambiguity of the exact mechanism in Ccp1, which could be applied to peroxidases with similar heme pockets. Discerning the feasibility of a no-water peroxidase mechanism in the doublet spin state irrespective of the environment surrounding the heme pocket.![]()
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Affiliation(s)
- Mohamed M Aboelnga
- Chemistry Department, Faculty of Science, Damietta University New Damietta 34517 Egypt
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4
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Zhang X, Jiang Y, Chen Q, Dong S, Feng Y, Cong Z, Shaik S, Wang B. H-Bonding Networks Dictate the Molecular Mechanism of H2O2 Activation by P450. ACS Catal 2021. [DOI: 10.1021/acscatal.1c02068] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Xuan Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Yiping Jiang
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, People’s Republic of China
| | - Qianqian Chen
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
| | - Sheng Dong
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, People’s Republic of China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, People’s Republic of China
| | - Zhiqi Cong
- CAS Key Laboratory of Biofuels and Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, People’s Republic of China
| | - Sason Shaik
- Institute of Chemistry, The Hebrew University of Jerusalem, 9190407 Jerusalem, Israel
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, People’s Republic of China
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5
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Yan L, Wang Y, Zhang S, Li X, Wei J, Wang Z, Liu Y. Inactivation Mechanism of Neuronal Nitric Oxide Synthase by ( S)-2-Amino-5-(2-(methylthio)acetimidamido)pentanoic Acid: Chemical Conversion of the Inactivator in the Active Site. Inorg Chem 2021; 60:9345-9358. [PMID: 34137256 DOI: 10.1021/acs.inorgchem.1c00046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Neuronal nitric oxide synthase (nNOS) is one of the three isoforms of nitric oxide synthase (NOS). The other two isoforms include inducible NOS (iNOS) and endothelial NOS (eNOS). These three isoforms of NOS are widely present in both human and other mammals and are responsible for the biosynthesis of NO. As an essential biological molecule, NO plays an essential role in neurotransmission, immune response, and vasodilation; however, the overproduction of NO can cause a series of diseases. Thus, the selective inhibition of three isoforms of NOS has been considered to be important in treating related diseases. The active sites of the three enzymes are highly conserved, causing the selective inhibition of the three enzymes to be a great challenge. (S)-2-Amino-5-(2-(methylthio)acetimidamido)pentanoic acid (1) has been experimentally proved to be a selective and time-dependent irreversible inhibitor of nNOS, and three pathways, including sulfide oxidation, oxidative dethiolation, and oxidative demethylation, have been suggested. In this work, we performed quantum mechanics/molecular mechanics calculations to verify the chemical conversion of inactivator 1. Although we agree with the previously suggested chemical transformation process, our calculations demonstrated that there are lower energy pathways to accomplish both oxidative dethiolation and oxidative demethylation. These three branching reactions are competitive, but only dethiolation and demethylation reactions can generate inhibitory intermediates. As a powerful time-dependent irreversible inhibitor of nNOS, the key sulfur atom and middle imine are all necessary. Our calculation results not only verified the chemical reaction of inhibitor 1 occurring in the enzymatic active site but also explained the inactivation mechanism of inhibitor 1. This is also the first verified example of the heme-enzyme-catalyzed S-demethylation mechanism.
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Affiliation(s)
- Lijuan Yan
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Yijing Wang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Shiqing Zhang
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Xinyi Li
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Jingjing Wei
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Zhiguo Wang
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
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6
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Su H, Wang B, Shaik S. Quantum-Mechanical/Molecular-Mechanical Studies of CYP11A1-Catalyzed Biosynthesis of Pregnenolone from Cholesterol Reveal a C-C Bond Cleavage Reaction That Occurs by a Compound I-Mediated Electron Transfer. J Am Chem Soc 2019; 141:20079-20088. [PMID: 31741382 DOI: 10.1021/jacs.9b08561] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We explore here a long-standing mechanistic question by using quantum-mechanical/molecular-mechanical (QM/MM) methodology. The question concerns the mechanism of steroid hormone biosynthesis, whereby the P450 enzyme, CYP11A1, catalyzes the C20-C22 bond-cleavage in the 20,22-hydroxylated cholesterol, 20R,22R-DiOHCH, leading to pregnenolone, which is critical for the subsequent production of all steroid hormones. This is an unusual feat whereby the P450 enzyme breaks two O-H bonds and one C-C bond, while making two C═O bonds. How does the enzyme perform such a complex and highly energy-demanding reaction? Our computational results rule out the previously proposed Compound I (Cpd I) electrophilic attack mechanism via the formation of a peroxide intermediate as well as the H-abstraction-mediated C-C cleavage mechanism. Notably, oxygen-rebound cannot transpire, in spite of the fact that the classical active species, Cpd I, participates in the catalytic process. Our findings reveal a mechanism whereby C-C bond cleavage is mediated by an electron transfer from the C22-O--deprotonated substrate to Cpd I. As such, our QM/MM calculations demonstrate that Cpd I acts as an electron sink that facilitates the C-C bond cleavage.
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Affiliation(s)
- Hao Su
- Institute of Chemistry , The Hebrew University of Jerusalem , 9190400 Jerusalem , Israel
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering , Xiamen University , Xiamen 360015 , P. R. China
| | - Sason Shaik
- Institute of Chemistry , The Hebrew University of Jerusalem , 9190400 Jerusalem , Israel
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7
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Wang K, Huang X, Lin K. Multiple catalytic roles of chloroperoxidase in the transformation of phenol: Products and pathways. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 179:96-103. [PMID: 31026755 DOI: 10.1016/j.ecoenv.2019.04.061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 04/15/2019] [Accepted: 04/19/2019] [Indexed: 06/09/2023]
Abstract
Chloroperoxidase (CPO) is a hybrid of two different families of enzymes, peroxidases and P450s. However, it is poorly understood on CPO's multiple catalytic functions. Herein, phenol was selected as a model substrate to investigate the multiple catalytic roles of CPO. Results showed that phenol was readily transformed into a variety of brominated organic compounds (BOCs) via the CPO-mediated oxidative process. A total of 16 BOCs were identified using gas and liquid chromatography coupled with mass spectrometry. Possible reaction pathways could be attributable to four CPO-mediated processes, including bromination, radical coupling, intramolecular cyclization and debromination. Higher bromide concentrations and lower pH conditions both facilitated the formation of brominated products. While a higher bromination capacity was observed in pH 3.0 solutions, CPO-mediated radical couplings were more favorable at pH 5.0 and 6.0. Although CPO might catalyze chlorination when chloride and bromide coexisted in the solution, BOCs were the dominant products of CPO-mediated phenol oxidation. Results of this study suggest that various catalytic roles of CPO may contribute to the biotic formation of BOCs in the natural environment.
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Affiliation(s)
- Kun Wang
- The Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Center for Marine Environmental Chemistry and Toxicology, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China
| | - Xinwen Huang
- College of Environment, Zhejiang University of Technology, Hangzhou, 310032, China
| | - Kunde Lin
- The Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Center for Marine Environmental Chemistry and Toxicology, College of the Environment and Ecology, Xiamen University, Xiamen, 361102, China.
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8
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Ramesh M, Bharatam PV. Formation of a Toxic Quinoneimine Metabolite from Diclofenac: A Quantum Chemical Study. Drug Metab Lett 2018; 13:64-76. [PMID: 30210009 DOI: 10.2174/1872312812666180913120736] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/27/2018] [Accepted: 08/27/2018] [Indexed: 01/26/2023]
Abstract
BACKGROUND Diclofenac is a non-steroidal antiinflammatory drug. It is predominantly metabolized by CYP2C9. 4'-hydroxydiclofenac and its quinoneimine are the metabolites of diclofenac. However, few numbers of serious cases of idiosyncratic hepatotoxicity due to diclofenac metabolism were reported. The formation of the quinoneimine metabolite was found to be responsible for this idiosyncratic toxicity. Quinoneimine is an over-oxidized metabolite of diclofenac. METHOD In this work, computational studies were conducted to detail the formation of a quinoneimine metabolite from diclofenac. Further, the idiosyncratic toxicity of quinoneimine due to its reactivity was also investigated by quantum chemical analysis. RESULTS & CONCLUSION The results demonstrate the possibility of formation of quinoneimine metabolite due to various factors that are involved in the metabolism of diclofenac. The present study may provide the structural in-sights during the drug development processes to avoid the metabolism directed idiosyncratic toxicity.
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Affiliation(s)
- Muthusamy Ramesh
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S.A.S. Nagar (Mohali)-160 062, India
| | - Prasad V Bharatam
- Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research (NIPER), Sector-67, S.A.S. Nagar (Mohali)-160 062, India
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9
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Wang WJ, Wei WJ, Liao RZ. Deciphering the chemoselectivity of nickel-dependent quercetin 2,4-dioxygenase. Phys Chem Chem Phys 2018; 20:15784-15794. [DOI: 10.1039/c8cp02683a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
QM/MM calculations were performed to elucidate the reaction mechanism and chemoselectivity of 2,4-QueD. The protonation state of the first-shell ligand Glu74 plays an important role in dictating the selectivity.
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Affiliation(s)
- Wen-Juan Wang
- Key Laboratory of Material Chemistry for Energy Conversion and Storage
- Ministry of Education
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica
- Hubei Key Laboratory of Materials Chemistry and Service Failure
- School of Chemistry and Chemical Engineering
| | - Wen-Jie Wei
- Key Laboratory of Material Chemistry for Energy Conversion and Storage
- Ministry of Education
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica
- Hubei Key Laboratory of Materials Chemistry and Service Failure
- School of Chemistry and Chemical Engineering
| | - Rong-Zhen Liao
- Key Laboratory of Material Chemistry for Energy Conversion and Storage
- Ministry of Education
- Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica
- Hubei Key Laboratory of Materials Chemistry and Service Failure
- School of Chemistry and Chemical Engineering
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10
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Morozov AN, Chatfield DC. How the Proximal Pocket May Influence the Enantiospecificities of Chloroperoxidase-Catalyzed Epoxidations of Olefins. Int J Mol Sci 2016; 17:E1297. [PMID: 27517911 PMCID: PMC5000694 DOI: 10.3390/ijms17081297] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 11/16/2022] Open
Abstract
Chloroperoxidase-catalyzed enantiospecific epoxidations of olefins are of significant biotechnological interest. Typical enantiomeric excesses are in the range of 66%-97% and translate into free energy differences on the order of 1 kcal/mol. These differences are generally attributed to the effect of the distal pocket. In this paper, we show that the influence of the proximal pocket on the electron transfer mechanism in the rate-limiting event may be just as significant for a quantitatively accurate account of the experimentally-measured enantiospecificities.
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Affiliation(s)
- Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th St., Miami, FL 33199, USA.
| | - David C Chatfield
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th St., Miami, FL 33199, USA.
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11
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Spectroscopic and QM/MM investigations of Chloroperoxidase catalyzed degradation of orange G. Arch Biochem Biophys 2016; 596:1-9. [DOI: 10.1016/j.abb.2016.02.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 02/05/2016] [Accepted: 02/24/2016] [Indexed: 11/30/2022]
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12
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Substrate ionization energy influences the epoxidation of m-substituted styrenes catalyzed by chloroperoxidase from Caldariomyces fumago. CATAL COMMUN 2016. [DOI: 10.1016/j.catcom.2016.01.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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13
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Mittra K, Singha A, Dey A. Iron porphyrins with a hydrogen bonding cavity: effect of weak interactions on their electronic structure and reactivity. Dalton Trans 2016; 45:18796-18802. [DOI: 10.1039/c6dt03597c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic structure and reactivity of iron porphyrin complexes bearing 2nd sphere hydrogen bonding residues have been investigated over the last few years.
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Affiliation(s)
- Kaustuv Mittra
- Department of Inorganic Chemistry
- Indian Association for the Cultivation of Science
- Kolkata
- India 700032
| | - Asmita Singha
- Department of Inorganic Chemistry
- Indian Association for the Cultivation of Science
- Kolkata
- India 700032
| | - Abhishek Dey
- Department of Inorganic Chemistry
- Indian Association for the Cultivation of Science
- Kolkata
- India 700032
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14
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Morozov AN, Pardillo AD, Chatfield DC. Chloroperoxidase-Catalyzed Epoxidation of Cis-β-Methylstyrene: NH-S Hydrogen Bonds and Proximal Helix Dipole Change the Catalytic Mechanism and Significantly Lower the Reaction Barrier. J Phys Chem B 2015; 119:14350-63. [PMID: 26452587 DOI: 10.1021/acs.jpcb.5b06731] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Proximal hydrogen bonding of the axial sulfur with the backbone amides (NH-S) is a conserved feature of heme-thiolate enzymes such as chloroperoxidase (CPO) and cytochrome P450 (P450). In CPO, the effect of NH-S bonds is amplified by the dipole moment of the proximal helix. Our gas-phase DFT studies show that the proximal pocket effect significantly enhances CPO's reactivity toward the epoxidation of olefinic substrates. Comparison of models with and without proximal pocket residues shows that with them, the barrier for Cβ-O bond formation is lowered by about ∼4.6 kcal/mol, while Cα-O-Cβ ring closure becomes barrierless. The dipole moment of the proximal helix was estimated to contribute 1/3 of the decrease, while the rest is attributed to the effect of NH-S bonds. The decrease of the reaction barrier correlates with increased electron density transfer to residues of the proximal pocket. The effect is most pronounced on the doublet spin surface and involves a change in the electron-transfer mechanism. A full enzyme QMMM study on the doublet spin surface gives about the same barrier as the gas-phase DFT study. The free-energy barrier was estimated to be in agreement with the experimental results for the CPO-catalyzed epoxidation of styrene.
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Affiliation(s)
- Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University , 11200 Southwest Eighth Street, Miami, Florida 33199, United States
| | - Armando D Pardillo
- Department of Chemistry and Biochemistry, Florida International University , 11200 Southwest Eighth Street, Miami, Florida 33199, United States
| | - David C Chatfield
- Department of Chemistry and Biochemistry, Florida International University , 11200 Southwest Eighth Street, Miami, Florida 33199, United States
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15
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Pardillo AD, Morozov AN, Chatfield DC. Proximal Pocket Hydrogen Bonds Significantly Influence the Mechanism of Chloroperoxidase Compound I Formation. J Phys Chem B 2015; 119:12590-602. [DOI: 10.1021/acs.jpcb.5b06324] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Armando D. Pardillo
- Department of Chemistry and
Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
| | - Alexander N. Morozov
- Department of Chemistry and
Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
| | - David C. Chatfield
- Department of Chemistry and
Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, United States
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16
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Chatterjee S, Sengupta K, Samanta S, Das PK, Dey A. Concerted Proton–Electron Transfer in Electrocatalytic O2 Reduction by Iron Porphyrin Complexes: Axial Ligands Tuning H/D Isotope Effect. Inorg Chem 2015; 54:2383-92. [DOI: 10.1021/ic5029959] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sudipta Chatterjee
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Kushal Sengupta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Subhra Samanta
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Pradip Kumar Das
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Abhishek Dey
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata 700032, India
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17
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Wei YL, Huang WS, Cui YM, Yang KF, Xu Z, Xu LW. Enantioselective cyanosilylation of aldehydes catalyzed by a multistereogenic salen–Mn(iii) complex with a rotatable benzylic group as a helping hand. RSC Adv 2015. [DOI: 10.1039/c4ra12884b] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A multistereogenic salen–Mn(iii) complex bearing an aromatic pocket and two benzylic groups as helping hands was found to be efficient in the catalysis of asymmetric cyanosilylation.
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Affiliation(s)
- Yun-Long Wei
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Wei-Sheng Huang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Yu-Ming Cui
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Ke-Fang Yang
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Zheng Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
| | - Li-Wen Xu
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education (MOE)
- Hangzhou Normal University
- Hangzhou 311121
- P. R. China
- State Key Laboratory for Oxo Synthesis and Selective Oxidation
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18
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Senn HM. Insights into enzymatic halogenation from computational studies. Front Chem 2014; 2:98. [PMID: 25426489 PMCID: PMC4227530 DOI: 10.3389/fchem.2014.00098] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 10/20/2014] [Indexed: 12/15/2022] Open
Abstract
The halogenases are a group of enzymes that have only come to the fore over the last 10 years thanks to the discovery and characterization of several novel representatives. They have revealed the fascinating variety of distinct chemical mechanisms that nature utilizes to activate halogens and introduce them into organic substrates. Computational studies using a range of approaches have already elucidated many details of the mechanisms of these enzymes, often in synergistic combination with experiment. This Review summarizes the main insights gained from these studies. It also seeks to identify open questions that are amenable to computational investigations. The studies discussed herein serve to illustrate some of the limitations of the current computational approaches and the challenges encountered in computational mechanistic enzymology.
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Affiliation(s)
- Hans M. Senn
- WestCHEM School of Chemistry, University of GlasgowGlasgow, UK
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19
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Hirao H, Thellamurege N, Zhang X. Applications of density functional theory to iron-containing molecules of bioinorganic interest. Front Chem 2014; 2:14. [PMID: 24809043 PMCID: PMC4010748 DOI: 10.3389/fchem.2014.00014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 03/10/2014] [Indexed: 12/29/2022] Open
Abstract
The past decades have seen an explosive growth in the application of density functional theory (DFT) methods to molecular systems that are of interest in a variety of scientific fields. Owing to its balanced accuracy and efficiency, DFT plays particularly useful roles in the theoretical investigation of large molecules. Even for biological molecules such as proteins, DFT finds application in the form of, e.g., hybrid quantum mechanics and molecular mechanics (QM/MM), in which DFT may be used as a QM method to describe a higher prioritized region in the system, while a MM force field may be used to describe remaining atoms. Iron-containing molecules are particularly important targets of DFT calculations. From the viewpoint of chemistry, this is mainly because iron is abundant on earth, iron plays powerful (and often enigmatic) roles in enzyme catalysis, and iron thus has the great potential for biomimetic catalysis of chemically difficult transformations. In this paper, we present a brief overview of several recent applications of DFT to iron-containing non-heme synthetic complexes, heme-type cytochrome P450 enzymes, and non-heme iron enzymes, all of which are of particular interest in the field of bioinorganic chemistry. Emphasis will be placed on our own work.
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Affiliation(s)
- Hajime Hirao
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological UniversitySingapore, Singapore
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20
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Li X, Zhang J, Jiang Y, Hu M, Li S, Zhai Q. Highly Efficient Biodecolorization/Degradation of Congo Red and Alizarin Yellow R by Chloroperoxidase from Caldariomyces fumago: Catalytic Mechanism and Degradation Pathway. Ind Eng Chem Res 2013. [DOI: 10.1021/ie4007563] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xuelian Li
- School
of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
| | - Juan Zhang
- School
of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
| | - Yucheng Jiang
- School
of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
- Key
Laboratory of Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi’an 710062, P. R. China
| | - Mancheng Hu
- School
of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
- Key
Laboratory of Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi’an 710062, P. R. China
| | - Shuni Li
- School
of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
- Key
Laboratory of Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi’an 710062, P. R. China
| | - Quanguo Zhai
- School
of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
- Key
Laboratory of Macromolecular Science of Shaanxi Province, Shaanxi Normal University, Xi’an 710062, P. R. China
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21
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Bushnell EAC, Gherib R, Gauld JW. Insights into the Catalytic Mechanism of Coral Allene Oxide Synthase: A Dispersion Corrected Density Functional Theory Study. J Phys Chem B 2013; 117:6701-10. [DOI: 10.1021/jp403405b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Eric A. C. Bushnell
- Department of Chemistry and Biochemistry,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - Rami Gherib
- Department of Chemistry and Biochemistry,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
| | - James W. Gauld
- Department of Chemistry and Biochemistry,
University of Windsor, Windsor, Ontario N9B 3P4, Canada
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22
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Zhang R, He Q, Chatfield D, Wang X. Paramagnetic nuclear magnetic resonance relaxation and molecular mechanics studies of the chloroperoxidase-indole complex: insights into the mechanism of chloroperoxidase-catalyzed regioselective oxidation of indole. Biochemistry 2013; 52:3688-701. [PMID: 23634952 DOI: 10.1021/bi4002437] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To unravel the mechanism of chloroperoxidase (CPO)-catalyzed regioselective oxidation of indole, we studied the structure of the CPO-indole complex using nuclear magnetic resonance (NMR) relaxation measurements and computational techniques. The dissociation constant (KD) of the CPO-indole complex was calculated to be approximately 21 mM. The distances (r) between protons of indole and the heme iron calculated via NMR relaxation measurements and molecular docking revealed that the pyrrole ring of indole is oriented toward the heme with its 2-H pointing directly at the heme iron. Both KD and r values are independent of pH in the range of 3.0-6.5. The stability and structure of the CPO-indole complex are also independent of the concentration of chloride or iodide ion. Molecular docking suggests the formation of a hydrogen bond between the NH group of indole and the carboxyl O of Glu 183 in the binding of indole to CPO. Simulated annealing of the CPO-indole complex using r values from NMR experiments as distance restraints reveals that the van der Waals interactions were much stronger than the Coulomb interactions in the binding of indole to CPO, indicating that the association of indole with CPO is primarily governed by hydrophobic rather than electrostatic interactions. This work provides the first experimental and theoretical evidence of the long-sought mechanism that leads to the "unexpected" regioselectivity of the CPO-catalyzed oxidation of indole. The structure of the CPO-indole complex will serve as a lighthouse in guiding the design of CPO mutants with tailor-made activities for biotechnological applications.
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Affiliation(s)
- Rui Zhang
- Department of Chemistry and Biochemistry, Florida International University , Miami, Florida 33199, United States
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23
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Vidal-Limón A, Águila S, Ayala M, Batista CV, Vazquez-Duhalt R. Peroxidase activity stabilization of cytochrome P450BM3 by rational analysis of intramolecular electron transfer. J Inorg Biochem 2013; 122:18-26. [DOI: 10.1016/j.jinorgbio.2013.01.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 11/17/2022]
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24
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Nandekar PP, Tumbi KM, Bansal N, Rathod VP, Labhsetwar LB, Soumya N, Singh S, Sangamwar AT. Chem-bioinformatics and in vitro approaches for candidate optimization: a case study of NSC745689 as a promising antitumor agent. Med Chem Res 2012. [DOI: 10.1007/s00044-012-0364-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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25
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Morozov AN, Chatfield DC. Chloroperoxidase-catalyzed epoxidation of cis-β-methylstyrene: distal pocket flexibility tunes catalytic reactivity. J Phys Chem B 2012; 116:12905-14. [PMID: 23020548 DOI: 10.1021/jp302763h] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Chloroperoxidase, the most versatile heme protein, has a hybrid active site pocket that shares structural features with peroxidases and cytochrome P450s. The simulation studies presented here show that the enzyme possesses a remarkable ability to efficiently utilize its hybrid structure, assuming structurally different peroxidase-like and P450-like distal pocket faces and thereby enhancing the inherent catalytic capability of the active center. We find that, during epoxidation of cis-β-methylstyrene (CBMS), the native peroxidase-like aspect of the distal pocket is diminished as the polar Glu183 side chain is displaced away from the active center and the distal pocket takes on a more hydrophobic, P450-like, aspect. The P450-like distal pocket provides a significant enthalpic stabilization of ∼4 kcal/mol of the 14 kcal/mol reaction barrier for gas-phase epoxidation of CMBS by an oxyferryl heme-thiolate species. This stabilization comes from breathing of the distal pocket. As until recently the active site of chloroperoxidase was postulated to be inflexible, these results suggest a new conceptual understanding of the enzyme's versatility: catalytic reactivity is tuned by flexibility of the distal pocket.
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Affiliation(s)
- Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
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26
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Isobe H, Yamaguchi K, Okumura M, Shimada J. Role of Perferryl–Oxo Oxidant in Alkane Hydroxylation Catalyzed by Cytochrome P450: A Hybrid Density Functional Study. J Phys Chem B 2012; 116:4713-30. [DOI: 10.1021/jp211184y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hiroshi Isobe
- Department of Chemistry, Graduate
School of Science, Osaka University, Toyonaka,
Osaka 560-0043, Japan
| | - Kizashi Yamaguchi
- Department of Chemistry, Graduate
School of Science, Osaka University, Toyonaka,
Osaka 560-0043, Japan
| | - Mitsutaka Okumura
- Department of Chemistry, Graduate
School of Science, Osaka University, Toyonaka,
Osaka 560-0043, Japan
| | - Jiro Shimada
- Green
Innovation Research Laboratories, NEC Corporation, 34, Miyukigaoka, Tsukuba, Ibaraki
305-8501, Japan
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27
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Usharani D, Zazza C, Lai W, Chourasia M, Waskell L, Shaik S. A single-site mutation (F429H) converts the enzyme CYP 2B4 into a heme oxygenase: a QM/MM study. J Am Chem Soc 2012; 134:4053-6. [PMID: 22356576 DOI: 10.1021/ja211905e] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The intriguing deactivation of the cytochrome P450 (CYP) 2B4 enzyme induced by mutation of a single residue, Phe429 to His, is explored by quantum mechanical/molecular mechanical calculations of the O-OH bond activation of the (Fe(3+)OOH)(-) intermediate. It is found that the F429H mutant of CYP 2B4 undergoes homolytic instead of heterolytic O-OH bond cleavage. Thus, the mutant acquires the following characteristics of a heme oxygenase enzyme: (a) donation by His429 of an additional NH---S H-bond to the cysteine ligand combined with the presence of the substrate retards the heterolytic cleavage and gives rise to homolytic O-OH cleavage, and (b) the Thr302/water cluster orients nascent OH(•) and ensures efficient meso hydroxylation.
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Affiliation(s)
- Dandamudi Usharani
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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28
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Capece L, Lewis-Ballester A, Yeh SR, Estrin DA, Marti MA. Complete reaction mechanism of indoleamine 2,3-dioxygenase as revealed by QM/MM simulations. J Phys Chem B 2012; 116:1401-13. [PMID: 22196056 PMCID: PMC3304497 DOI: 10.1021/jp2082825] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Indoleamine 2,3-dioxygenase (IDO) and tryptophan dioxygenase (TDO) are two heme proteins that catalyze the oxidation reaction of tryptophan (Trp) to N-formylkynurenine (NFK). Human IDO (hIDO) has recently been recognized as a potent anticancer drug target, a fact that triggered intense research on the reaction and inhibition mechanisms of hIDO. Our recent studies revealed that the dioxygenase reaction catalyzed by hIDO and TDO is initiated by addition of the ferric iron-bound superoxide to the C(2)═C(3) bond of Trp to form a ferryl and Trp-epoxide intermediate, via a 2-indolenylperoxo radical transition state. The data demonstrate that the two atoms of dioxygen are inserted into the substrate in a stepwise fashion, challenging the paradigm of heme-based dioxygenase chemistry. In the current study, we used QM/MM methods to decipher the mechanism by which the second ferryl oxygen is inserted into the Trp-epoxide to form the NFK product in hIDO. Our results show that the most energetically favored pathway involves proton transfer from Trp-NH(3)(+) to the epoxide oxygen, triggering epoxide ring opening and a concerted nucleophilic attack of the ferryl oxygen to the C(2) of Trp that leads to a metastable reaction intermediate. This intermediate subsequently converts to NFK, following C(2)-C(3) bond cleavage and the associated back proton transfer from the oxygen to the amino group of Trp. A comparative study with Xantomonas campestris TDO (xcTDO) indicates that the reaction follows a similar pathway, although subtle differences distinguishing the two enzyme reactions are evident. The results underscore the importance of the NH(3)(+) group of Trp in the two-step ferryl-based mechanism of hIDO and xcTDO, by acting as an acid catalyst to facilitate the epoxide ring-opening reaction and ferryl oxygen addition to the indole ring.
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Affiliation(s)
- Luciana Capece
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET
| | - Ariel Lewis-Ballester
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 USA
| | - Syun-Ru Yeh
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York 10461 USA
| | - Dario A. Estrin
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET
| | - Marcelo A. Marti
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires, C1428EHA, Argentina
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29
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Hirao H, Li F, Que L, Morokuma K. Theoretical study of the mechanism of oxoiron(IV) formation from H2O2 and a nonheme iron(II) complex: O-O cleavage involving proton-coupled electron transfer. Inorg Chem 2011; 50:6637-48. [PMID: 21678930 PMCID: PMC3136038 DOI: 10.1021/ic200522r] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It has recently been shown that the nonheme oxoiron(IV) species supported by the 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane ligand (TMC) can be generated in near-quantitative yield by reacting [Fe(II)(TMC)(OTf)(2)] with a stoichiometric amount of H(2)O(2) in CH(3)CN in the presence of 2,6-lutidine (Li, F.; England, J.; Que, L., Jr. J. Am. Chem. Soc. 2010, 132, 2134-2135). This finding has major implications for O-O bond cleavage events in both Fenton chemistry and nonheme iron enzymes. To understand the mechanism of this process, especially the intimate details of the O-O bond cleavage step, a series of density functional theory (DFT) calculations and analyses have been carried out. Two distinct reaction paths (A and B) were identified. Path A consists of two principal steps: (1) coordination of H(2)O(2) to Fe(II) and (2) a combination of partial homolytic O-O bond cleavage and proton-coupled electron transfer (PCET). The latter combination renders the rate-limiting O-O cleavage effectively a heterolytic process. Path B proceeds via a simultaneous homolytic O-O bond cleavage of H(2)O(2) and Fe-O bond formation. This is followed by H abstraction from the resultant Fe(III)-OH species by an •OH radical. Calculations suggest that path B is plausible in the absence of base. However, once 2,6-lutidine is added to the reacting system, the reaction barrier is lowered and more importantly the mechanistic path switches to path A, where 2,6-lutidine plays an essential role as an acid-base catalyst in a manner similar to how the distal histidine or glutamate residue assists in compound I formation in heme peroxidases. The reaction was found to proceed predominantly on the quintet spin state surface, and a transition to the triplet state, the experimentally known ground state for the TMC-oxoiron(IV) species, occurs in the last stage of the oxoiron(IV) formation process.
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Affiliation(s)
- Hajime Hirao
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
| | - Feifei Li
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
| | - Lawrence Que
- Department of Chemistry and Center for Metals in Biocatalysis, University of Minnesota, 207 Pleasant Street SE, Minneapolis, MN 55455, USA
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano Nishihiraki-cho, Sakyo, Kyoto 606-8103, Japan
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30
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Chen H, Lai W, Shaik S. Multireference and multiconfiguration ab initio methods in heme-related systems: what have we learned so far? J Phys Chem B 2011; 115:1727-42. [PMID: 21344948 DOI: 10.1021/jp110016u] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
This work reviews the recent applications of ab initio multireference/multiconfiguration (MR/MC) electronic structure methods to heme-related systems, involving tetra-, penta-, and hexa-coordinate species, as well as the high-valent iron-oxo species. The current accuracy of these methods in the various systems is discussed, with special attention to potential sources of systematic errors. Thus, the review summarizes and tries to rationalize the key elements of MR/MC calculations, namely, the choice of the employed active space, especially the so-called double-shell effect that has already been recognized to be important in transition-metal-containing systems, and the impact of these elements on the spin-state energetics of heme species, as well as on the bonding mechanism of small molecules to the heme. It is shown that expansion of the MC wave function into one based on localized orbitals provides a compact and insightful view on some otherwise complex electronic structures. The effects of protein environment on the MR/MC results are summarized for the few available quantum mechanical/molecular mechanical (QM/MM) studies. Comparisons with corresponding DFT results are also made wherever available. Potential future directions are proposed.
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Affiliation(s)
- Hui Chen
- Institute of Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel.
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31
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Morozov AN, D'Cunha C, Alvarez CA, Chatfield DC. Enantiospecificity of chloroperoxidase-catalyzed epoxidation: biased molecular dynamics study of a cis-β-methylstyrene/chloroperoxidase-compound I complex. Biophys J 2011; 100:1066-75. [PMID: 21320452 DOI: 10.1016/j.bpj.2010.12.3729] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 11/22/2010] [Accepted: 12/20/2010] [Indexed: 11/17/2022] Open
Abstract
Molecular dynamics simulations of an explicitly solvated cis-β-methylstyrene/chloroperoxidase-Compound I complex are performed to determine the cause of the high enantiospecificity of epoxidation. From the simulations, a two-dimensional free energy potential is calculated to distinguish binding potential wells from which reaction to 1S2R and 1R2S epoxide products may occur. Convergence of the free energy potential is accelerated with an adaptive biasing potential. Analysis of binding is followed by analysis of 1S2R and 1R2S reaction precursor structures in which the substrate, having left the binding wells, places its reactive double bond in steric proximity to the oxyferryl heme center. Structural analysis of binding and reaction precursor conformations is presented. We find that 1), a distortion of Glu(183) is important for CPO-catalyzed epoxidation as was postulated previously based on experimental results; 2), the free energy of binding does not provide significant differentiation between structures leading to the respective epoxide enantiomers; and 3), CPO's enantiospecificity toward cis-β-methylstyrene is likely to be caused by a specific group of residues which form a hydrophobic core surrounding the oxyferryl heme center.
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Affiliation(s)
- Alexander N Morozov
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida, USA.
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32
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Alfonso-Prieto M, Oberhofer H, Klein ML, Rovira C, Blumberger J. Proton Transfer Drives Protein Radical Formation in Helicobacter pylori Catalase but Not in Penicillium vitale Catalase. J Am Chem Soc 2011; 133:4285-98. [DOI: 10.1021/ja1110706] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- M. Alfonso-Prieto
- Computer Simulation & Modeling Laboratory, Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Spain
- Institute for Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122, United States
| | - H. Oberhofer
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
| | - M. L. Klein
- Institute for Computational Molecular Science, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122, United States
| | - C. Rovira
- Computer Simulation & Modeling Laboratory, Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Spain
- Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - J. Blumberger
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
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33
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Kinetic study of the oxidative dehalogenation of 2,4,6-trichlorophenol catalyzed by chloroperoxidase. ACTA ACUST UNITED AC 2010. [DOI: 10.1016/j.molcatb.2010.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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34
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Lai W, Chen H, Matsui T, Omori K, Unno M, Ikeda-Saito M, Shaik S. Enzymatic Ring-Opening Mechanism of Verdoheme by the Heme Oxygenase: A Combined X-ray Crystallography and QM/MM Study. J Am Chem Soc 2010; 132:12960-70. [DOI: 10.1021/ja104674q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Wenzhen Lai
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Hui Chen
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Toshitaka Matsui
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Kohei Omori
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Masaki Unno
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Masao Ikeda-Saito
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira, Sendai, 980-8577, Japan
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35
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Chung LW, Li X, Sugimoto H, Shiro Y, Morokuma K. ONIOM Study on a Missing Piece in Our Understanding of Heme Chemistry: Bacterial Tryptophan 2,3-Dioxygenase with Dual Oxidants. J Am Chem Soc 2010; 132:11993-2005. [DOI: 10.1021/ja103530v] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Lung Wa Chung
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Xin Li
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Hiroshi Sugimoto
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Yoshitsugu Shiro
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
| | - Keiji Morokuma
- Fukui Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan, and Biometal Science Laboratory, RIKEN SPring-8 Center, Harima Institute, Hyogo 679-5148, Japan
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36
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Vidossich P, Fiorin G, Alfonso-Prieto M, Derat E, Shaik S, Rovira C. On the role of water in peroxidase catalysis: a theoretical investigation of HRP compound I formation. J Phys Chem B 2010; 114:5161-9. [PMID: 20345187 DOI: 10.1021/jp911170b] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have investigated the dynamics of water molecules in the distal pocket of horseradish peroxidase to elucidate the role that they may play in the formation of the principal active species of the enzymatic cycle (compound I, Por(o+)-Fe(IV)=O) upon reaction of the resting Fe(III) state with hydrogen peroxide. The equilibrium molecular dynamics simulations show that, in accord with experimental evidence, the active site access channel is hydrated with an average of two to three water molecules within 5 A from the bound hydrogen peroxide. Although the channel is always hydrated, the specific conformations in which a water molecule bridges H(2)O(2) and the distal histidine, which were found (Derat; et al. J. Am. Chem. Soc. 2007, 129, 6346.) to display a low-energy barrier for the initial acid-base step of the reaction, occur with low probability but are relevant within the time scale of catalysis. Metadynamics simulations, which were used to reconstruct the free-energy landscape of water motion in the access channel, revealed that preferred interaction sites within the channel are separated by small energy barriers (<1.5 kcal/mol). Most importantly, water-bridged conformations lie on a shoulder just 1 kcal/mol above one local minimum and thus are easily accessible. Such an energy landscape appears as a requisite for the effectiveness of compound I formation, whereby the H-bonding pattern involving reactants and catalytic residues (including the intervening water molecule) has to rearrange to deliver the proton to the distal OH moiety of the hydrogen peroxide and thereby lead to heterolytic O-O cleavage. Our study provides an example of a system for which the "reactive configurations" (i.e., structures characterized by a low barrier for the chemical transformation) correspond to a minor population of the system and show how equilibrium molecular dynamics and free-energy calculations may conveniently be used to ascertain that such reactive conformations are indeed accessible to the system. Once again, the MD and QM/MM combination shows that a single water molecule acts as a biocatalyst in the cycle of HRP.
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Affiliation(s)
- Pietro Vidossich
- Laboratori de Simulació Computacional i Modelització, Parc Científic de Barcelona, Josep Samitier 1-5, 08028 Barcelona, Spain
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37
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Coupling and uncoupling mechanisms in the methoxythreonine mutant of cytochrome P450cam: a quantum mechanical/molecular mechanical study. J Biol Inorg Chem 2010; 15:361-72. [PMID: 20225401 PMCID: PMC2830628 DOI: 10.1007/s00775-009-0608-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The Thr252 residue plays a vital role in the catalytic cycle of cytochrome P450cam during the formation of the active species (Compound I) from its precursor (Compound 0). We investigate the effect of replacing Thr252 by methoxythreonine (MeO-Thr) on this protonation reaction (coupling) and on the competing formation of the ferric resting state and H2O2 (uncoupling) by combined quantum mechanical/molecular mechanical (QM/MM) methods. For each reaction, two possible mechanisms are studied, and for each of these the residues Asp251 and Glu366 are considered as proton sources. The computed QM/MM barriers indicate that uncoupling is unfavorable in the case of the Thr252MeO-Thr mutant, whereas there are two energetically feasible proton transfer pathways for coupling. The corresponding rate-limiting barriers for the formation of Compound I are higher in the mutant than in the wild-type enzyme. These findings are consistent with the experimental observations that the Thr252MeO-Thr mutant forms the alcohol product exclusively (via Compound I), but at lower reaction rates compared with the wild-type enzyme.
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38
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Chen H, Song J, Lai W, Wu W, Shaik S. Multiple Low-Lying States for Compound I of P450cam and Chloroperoxidase Revealed from Multireference Ab Initio QM/MM Calculations. J Chem Theory Comput 2010; 6:940-53. [DOI: 10.1021/ct9006234] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hui Chen
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, State Key Laboratory of Physical Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, P. R. China
| | - Jinshuai Song
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, State Key Laboratory of Physical Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, P. R. China
| | - Wenzhen Lai
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, State Key Laboratory of Physical Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, P. R. China
| | - Wei Wu
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, State Key Laboratory of Physical Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, P. R. China
| | - Sason Shaik
- Institute of Chemistry and the Lise Meitner-Minerva Center for Computational Quantum Chemistry, Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel, State Key Laboratory of Physical Chemistry and Chemical Engineering, Xiamen University, 361005 Xiamen, P. R. China
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39
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Lai W, Chen H, Cho KB, Shaik S. Effects of substrate, protein environment, and proximal ligand mutation on compound I and compound 0 of chloroperoxidase. J Phys Chem A 2010; 113:11763-71. [PMID: 19572690 DOI: 10.1021/jp902898s] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This paper investigates the enzyme chloroperoxidase (CPO) by means of hybrid quantum mechanical/molecular mechanical (QM/MM) calculations. The effects of anionic substrate, protein environment, and proximal ligand mutation on the high-valent iron-oxo species, compound I (Cpd I), and the ferric hydroperoxide complex, compound 0 (Cpd 0), are studied. The results indicate that the presence of an anionic substrate (acetate) and the protonation state of one critical residue (Glu104) have a considerable impact on the relative stabilities of Cpd I and Cpd 0. In the absence of the substrate or when the substrate is protonated, Cpd I is considerably more stable, and its formation barrier is smaller than in the case where the substrate is in its anionic state and when Glu104 is deprotonated. This trend, which is shown to be a simple manifestation of the Hammond principle, reproduces the experimental observation that the working pH of the enzyme is acidic. Furthermore, in the absence of substrate (or when it is protonated), the relative Cpd 0/Cpd I energies are found to be a good index of Cpd I stability in heme enzymes and to follow the experimental order: horseradish peroxidase (HRP) > CPO > P450. In silico mutation of the proximal ligand from cysteine to selenocysteine was found to have no effect at all on the properties of Cpd I (e.g., spin density on the chalcogen, Mössbauer parameters, etc.) and its relative stability to Cpd 0 or on the corresponding barrier for formation. This surprising finding shows that the polar CPO pocket applies a leveling effect that stabilizes the anionic forms of the proximal ligands (CysS(-) and CysSe(-)). This in turn means that the Se-Cpd I of the mutant CPO is observable.
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Affiliation(s)
- Wenzhen Lai
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel
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40
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Krishnan S, Abeykoon A, Schenkman JB, Rusling JF. Control of electrochemical and ferryloxy formation kinetics of cyt P450s in polyion films by heme iron spin state and secondary structure. J Am Chem Soc 2010; 131:16215-24. [PMID: 19886700 DOI: 10.1021/ja9065317] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Voltammetry of cytochrome P450 (cyt P450) enzymes in ultrathin films with polyions was related for the first time to electronic and secondary structure. Heterogeneous electron transfer (hET) rate constants for reduction of the cyt P450s depended on heme iron spin state, with low spin cyt P450cam giving a value 40-fold larger than high spin human cyt P450 1A2, with mixed spin human P450 cyt 2E1 at an intermediate value. Asymmetric reduction-oxidation peak separations with increasing scan rates were explained by simulations featuring faster oxidation than reduction. Results are consistent with a square scheme in which oxidized and reduced forms of cyt P450s each participate in rapid conformational equilibria. Rate constants for oxidation of ferric cyt P450s in films by t-butyl hydroperoxide to active ferryloxy cyt P450s from rotating disk voltammetry suggested a weaker dependence on spin state, but in the reverse order of the observed hET reduction rates. Oxidation and reduction rates of cyt P450s in the films are also likely to depend on protein secondary structure around the heme iron.
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Affiliation(s)
- Sadagopan Krishnan
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, USA
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41
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Jing YQ, Han KL. Quantum mechanical effect in protein–ligand interaction. Expert Opin Drug Discov 2009; 5:33-49. [DOI: 10.1517/17460440903440127] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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42
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Davydov R, Sudhamsu J, Lees NS, Crane BR, Hoffman BM. EPR and ENDOR characterization of the reactive intermediates in the generation of NO by cryoreduced oxy-nitric oxide synthase from Geobacillus stearothermophilus. J Am Chem Soc 2009; 131:14493-507. [PMID: 19754116 DOI: 10.1021/ja906133h] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cryoreduction EPR/ENDOR/step-annealing measurements with substrate complexes of oxy-gsNOS (3; gsNOS is nitric oxide synthase from Geobacillus stearothermophilus) confirm that Compound I (6) is the reactive heme species that carries out the gsNOS-catalyzed (Stage I) oxidation of L-arginine to N-hydroxy-L-arginine (NOHA), whereas the active species in the (Stage II) oxidation of NOHA to citrulline and HNO/NO(-) is the hydroperoxy-ferric form (5). When 3 is reduced by tetrahydrobiopterin (BH4), instead of an externally supplied electron, the resulting BH4(+) radical oxidizes HNO/NO(-) to NO. In this report, radiolytic one-electron reduction of 3 and its complexes with Arg, Me-Arg, and NO(2)Arg was shown by EPR and (1)H and (14,15)N ENDOR spectroscopies to generate 5; in contrast, during cryoreduction of 3/NOHA, the peroxo-ferric-gsNOS intermediate (4/NOHA) was trapped. During annealing at 145 K, ENDOR shows that 5/Arg and 5/Me-Arg (but not 5/NO(2)Arg) generate a Stage I primary product species in which the OH group of the hydroxylated substrate is coordinated to Fe(III), characteristic of 6 as the active heme center. Analysis shows that hydroxylation of Arg and Me-Arg is quantitative. Annealing of 4/NOHA at 160 K converts it first to 5/NOHA and then to the Stage II primary enzymatic product. The latter contains Fe(III) coordinated by water, characteristic of 5 as the active heme center. It further contains quantitative amounts of citrulline and HNO/NO(-); the latter reacts with the ferriheme to form the NO-ferroheme upon further annealing. Stage I delivery of the first proton of catalysis to the (unobserved) 4 formed by cryoreduction of 3 involves a bound water that may convey a proton from L-Arg, while the second proton likely derives from the carboxyl side chain of Glu 248 or the heme carboxylates; the process also involves proton delivery by water(s). In the Stage II oxidation of NOHA, the proton that converts 4/NOHA to 5/NOHA likely is derived from NOHA itself, a conclusion supported by the pH invariance of the process. The present results illustrate how the substrate itself modulates the nature and reactivity of intermediates along the monooxygenase reaction pathway.
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Affiliation(s)
- Roman Davydov
- Chemistry Department, Northwestern University, Evanston, Illinois 60208-3113, USA
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43
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Cramer CJ, Truhlar DG. Density functional theory for transition metals and transition metal chemistry. Phys Chem Chem Phys 2009; 11:10757-816. [PMID: 19924312 DOI: 10.1039/b907148b] [Citation(s) in RCA: 1079] [Impact Index Per Article: 71.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
We introduce density functional theory and review recent progress in its application to transition metal chemistry. Topics covered include local, meta, hybrid, hybrid meta, and range-separated functionals, band theory, software, validation tests, and applications to spin states, magnetic exchange coupling, spectra, structure, reactivity, and catalysis, including molecules, clusters, nanoparticles, surfaces, and solids.
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Affiliation(s)
- Christopher J Cramer
- Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, MN 55455-0431, USA.
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44
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Shaik S, Cohen S, Wang Y, Chen H, Kumar D, Thiel W. P450 Enzymes: Their Structure, Reactivity, and Selectivity—Modeled by QM/MM Calculations. Chem Rev 2009; 110:949-1017. [DOI: 10.1021/cr900121s] [Citation(s) in RCA: 791] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sason Shaik
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Shimrit Cohen
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Yong Wang
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Hui Chen
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Devesh Kumar
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
| | - Walter Thiel
- Institute of Chemistry and the Lise-Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel, and Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, D-45470 Mülheim an der Ruhr, Germany
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45
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Dey A, Jiang Y, Ortiz de Montellano P, Hodgson KO, Hedman B, Solomon EI. S K-edge XAS and DFT calculations on cytochrome P450: covalent and ionic contributions to the cysteine-Fe bond and their contribution to reactivity. J Am Chem Soc 2009; 131:7869-78. [PMID: 19438234 DOI: 10.1021/ja901868q] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Experimental covalencies of the Fe-S bond for the resting low-spin and substrate-bound high-spin active site of cytochrome P450 are reported. DFT calculations on the active site indicate that one H-bonding interaction from the protein backbone is needed to reproduce the experimental values. The H-bonding to the thiolate from the backbone decreases the anisotropic pi covalency of the Fe-S bond lowering the barrier of free rotation of the exchangeable axial ligand, which is important for reactivity. The anionic axial thiolate ligand is calculated to lower the Fe(III/II) reduction potential of the active site by more than 1 V compared to a neutral imidazole ligand. About half of this derives from its covalent bonding and half from its electrostatic interaction with the oxidized Fe. This axial thiolate ligand increases the pK(a) of compound 0 (Fe(III)-hydroperoxo) favoring its protonation which promotes O-O bond heterolysis forming compound I. The reactivity of compound I is calculated to be relatively insensitive to the nature of the axial ligand due to opposing reduction potential and proton affinity contributions to the H-atom abstraction energy.
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Affiliation(s)
- Abhishek Dey
- Department of Chemistry, Stanford University, Stanford, California 94305, USA
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46
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Lai W, Chen H, Shaik S. What Kinds of Ferryl Species Exist for Compound II of Chloroperoxidase? A Dialog of Theory with Experiment. J Phys Chem B 2009; 113:7912-7. [DOI: 10.1021/jp902288q] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Wenzhen Lai
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel
| | - Hui Chen
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Computational Quantum Chemistry, The Hebrew University of Jerusalem, Givat Ram Campus, 91904 Jerusalem, Israel
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47
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Cho KB, Carvajal MA, Shaik S. First Half-Reaction Mechanism of Nitric Oxide Synthase: The Role of Proton and Oxygen Coupled Electron Transfer in the Reaction by Quantum Mechanics/Molecular Mechanics. J Phys Chem B 2008; 113:336-46. [DOI: 10.1021/jp8073199] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kyung-Bin Cho
- Institute of Chemistry and The Lise Meitner-Minerva Center for Quantum Computational Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Maria Angels Carvajal
- Institute of Chemistry and The Lise Meitner-Minerva Center for Quantum Computational Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
| | - Sason Shaik
- Institute of Chemistry and The Lise Meitner-Minerva Center for Quantum Computational Chemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel
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