1
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Skinner KC, Kammeraad JA, Wymore T, Narayan ARH, Zimmerman PM. Simulating Electron Transfer Reactions in Solution: Radical-Polar Crossover. J Phys Chem B 2023; 127:10097-10107. [PMID: 37976536 DOI: 10.1021/acs.jpcb.3c06120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Single-electron transfer (SET) promotes a wide variety of interesting chemical transformations, but modeling of SET requires a careful treatment of electronic and solvent effects to give meaningful insight. Therefore, a combined constrained density functional theory and molecular mechanics (CDFT/MM) tool is introduced specifically for SET-initiated reactions. Mechanisms for two radical-polar crossover reactions involving the organic electron donors tetrakis(dimethylamino)ethylene (TDAE) and tetrathiafulvalene (TTF) were studied with the new tool. An unexpected tertiary radical intermediate within the TDAE system was identified, relationships between kinetics and substitution in the TTF system were explained, and the impact of the solvent environments on the TDAE and TTF reactions were examined. The results highlight the need for including solvent dynamics when quantifying SET kinetics and thermodynamics, as a free energy difference of >20 kcal/mol was observed. Overall, the new method informs mechanistic analysis of SET-initiated reactions and therefore is envisioned to be useful for studying reactions in the condensed phase.
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Affiliation(s)
- Kevin C Skinner
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Josh A Kammeraad
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Troy Wymore
- Laufer Center, Stony Brook University, Stony Brook, New York 11794, United States
| | - Alison R H Narayan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Paul M Zimmerman
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Sargolzaei M, Nikoofard H. Design of prodrug for stereoisomers of omapatrilat to cross the blood-brain barrier using docking, homology modeling, MD, and QM/MM methods. J Biomol Struct Dyn 2023:1-13. [PMID: 37728537 DOI: 10.1080/07391102.2023.2259488] [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: 06/02/2023] [Accepted: 09/09/2023] [Indexed: 09/21/2023]
Abstract
In this study, we designed a suitable ester prodrug for omapatrilat to penetrate the blood-brain barrier and treat CNS diseases. Based on the ADMET properties, the methyl carboxylate ester of omapatrilat was chosen from among several prodrug structures. Sixteen methyl carboxylate esters were constructed for omapatrilat. The structure of brain carboxylesterase was derived via homology modeling, and molecular docking was used to determine the most potent stereoisomers against brain carboxylesterase. The top three stereoisomer complexes, and the apo form of the protein, were then considered using molecular dynamics simulation and MM/GBSA analysis. Following the simulation, structural analysis was performed using RMSD, RMSF, Rg, and hydrogen bond analysis tools. Our data demonstrated that the prodrug of RSSR is a suitable structure for crossing the blood-brain barrier and binding to brain carboxylesterase. In addition, we found via QM/MM calculation that the catalytic reaction of the prodrug of RSSR against brain carboxylesterase occurs via two steps, including acylation and diacylation steps. Based on our findings, we propose a clinical trial of a methyl carboxylate ester prodrug of omapatrilat's RSSR for the treatment of brain diseases.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Mohsen Sargolzaei
- Faculty of Chemistry, Shahrood University of Technology, Shahrood, Iran
| | - Hossein Nikoofard
- Faculty of Chemistry, Shahrood University of Technology, Shahrood, Iran
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3
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Clemente CM, Capece L, Martí MA. Best Practices on QM/MM Simulations of Biological Systems. J Chem Inf Model 2023; 63:2609-2627. [PMID: 37100031 DOI: 10.1021/acs.jcim.2c01522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
During the second half of the 20th century, following structural biology hallmark works on DNA and proteins, biochemists shifted their questions from "what does this molecule look like?" to "how does this process work?". Prompted by the theoretical and practical developments in computational chemistry, this led to the emergence of biomolecular simulations and, along with the 2013 Nobel Prize in Chemistry, to the development of hybrid QM/MM methods. QM/MM methods are necessary whenever the problem we want to address involves chemical reactivity and/or a change in the system's electronic structure, with archetypal examples being the studies of an enzyme's reaction mechanism and a metalloprotein's active site. In the last decades QM/MM methods have seen an increasing adoption driven by their incorporation in widely used biomolecular simulation software. However, properly setting up a QM/MM simulation is not an easy task, and several issues need to be properly addressed to obtain meaningful results. In the present work, we describe both the theoretical concepts and practical issues that need to be considered when performing QM/MM simulations. We start with a brief historical perspective on the development of these methods and describe when and why QM/MM methods are mandatory. Then we show how to properly select and analyze the performance of the QM level of theory, the QM system size, and the position and type of the boundaries. We show the relevance of performing prior QM model system (or QM cluster) calculations in a vacuum and how to use the corresponding results to adequately calibrate those derived from QM/MM. We also discuss how to prepare the starting structure and how to select an adequate simulation strategy, including those based on geometry optimizations as well as free energy methods. In particular, we focus on the determination of free energy profiles using multiple steered molecular dynamics (MSMD) combined with Jarzynski's equation. Finally, we describe the results for two illustrative and complementary examples: the reaction performed by chorismate mutase and the study of ligand binding to hemoglobins. Overall, we provide many practical recommendations (or shortcuts) together with important conceptualizations that we hope will encourage more and more researchers to incorporate QM/MM studies into their research projects.
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Affiliation(s)
- Camila M Clemente
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEyN-UBA) e Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Pabellón 2 de Ciudad Universitaria, Ciudad de Buenos Aires C1428EHA, Argentina
| | - Luciana Capece
- Departamento de Química Inorgánica Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEyN-UBA) e Instituto de Química de los Materiales, Ambiente y Energía (INQUIMAE) CONICET, Pabellòn 2 de Ciudad Universitaria, Ciudad de Buenos Aires C1428EHA, Argentina
| | - Marcelo A Martí
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires (FCEyN-UBA) e Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN) CONICET, Pabellón 2 de Ciudad Universitaria, Ciudad de Buenos Aires C1428EHA, Argentina
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4
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Elena-Real CA, Sagar A, Urbanek A, Popovic M, Morató A, Estaña A, Fournet A, Doucet C, Lund XL, Shi ZD, Costa L, Thureau A, Allemand F, Swenson RE, Milhiet PE, Crehuet R, Barducci A, Cortés J, Sinnaeve D, Sibille N, Bernadó P. The structure of pathogenic huntingtin exon 1 defines the bases of its aggregation propensity. Nat Struct Mol Biol 2023; 30:309-320. [PMID: 36864173 DOI: 10.1038/s41594-023-00920-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/05/2023] [Indexed: 03/04/2023]
Abstract
Huntington's disease is a neurodegenerative disorder caused by a CAG expansion in the first exon of the HTT gene, resulting in an extended polyglutamine (poly-Q) tract in huntingtin (httex1). The structural changes occurring to the poly-Q when increasing its length remain poorly understood due to its intrinsic flexibility and the strong compositional bias. The systematic application of site-specific isotopic labeling has enabled residue-specific NMR investigations of the poly-Q tract of pathogenic httex1 variants with 46 and 66 consecutive glutamines. Integrative data analysis reveals that the poly-Q tract adopts long α-helical conformations propagated and stabilized by glutamine side chain to backbone hydrogen bonds. We show that α-helical stability is a stronger signature in defining aggregation kinetics and the structure of the resulting fibrils than the number of glutamines. Our observations provide a structural perspective of the pathogenicity of expanded httex1 and pave the way to a deeper understanding of poly-Q-related diseases.
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Affiliation(s)
- Carlos A Elena-Real
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Amin Sagar
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Annika Urbanek
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Matija Popovic
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Anna Morató
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Alejandro Estaña
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
- LAAS-CNRS, University of Toulouse, CNRS, Toulouse, France
| | - Aurélie Fournet
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Christine Doucet
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Xamuel L Lund
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
- Institute of Laue Langevin, Grenoble, France
| | - Zhen-Dan Shi
- The Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | - Luca Costa
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | | | - Frédéric Allemand
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Rolf E Swenson
- The Chemistry and Synthesis Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Rockville, MD, USA
| | | | - Ramon Crehuet
- Institute for Advanced Chemistry of Catalonia (IQAC), CSIC, Barcelona, Spain
| | - Alessandro Barducci
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Juan Cortés
- LAAS-CNRS, University of Toulouse, CNRS, Toulouse, France
| | - Davy Sinnaeve
- Univ. Lille, INSERM, CHU Lille, Institut Pasteur de Lille, U1167 - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, Lille, France
- CNRS, EMR9002, Integrative Structural Biology, Lille, France
| | - Nathalie Sibille
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France
| | - Pau Bernadó
- Centre for Structural Biology, University of Montpellier, INSERM, CNRS, Montpellier, France.
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5
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Cárdenas G, Lucia‐Tamudo J, Mateo‐delaFuente H, Palmisano VF, Anguita‐Ortiz N, Ruano L, Pérez‐Barcia Á, Díaz‐Tendero S, Mandado M, Nogueira JJ. MoBioTools: A toolkit to setup quantum mechanics/molecular mechanics calculations. J Comput Chem 2023; 44:516-533. [PMID: 36507763 PMCID: PMC10107847 DOI: 10.1002/jcc.27018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 12/15/2022]
Abstract
We present a toolkit that allows for the preparation of QM/MM input files from a conformational ensemble of molecular geometries. The package is currently compatible with trajectory and topology files in Amber, CHARMM, GROMACS and NAMD formats, and has the possibility to generate QM/MM input files for Gaussian (09 and 16), Orca (≥4.0), NWChem and (Open)Molcas. The toolkit can be used in command line, so that no programming experience is required, although it presents some features that can also be employed as a python application programming interface. We apply the toolkit in four situations in which different electronic-structure properties of organic molecules in the presence of a solvent or a complex biological environment are computed: the reduction potential of the nucleobases in acetonitrile, an energy decomposition analysis of tyrosine interacting with water, the absorption spectrum of an azobenzene derivative integrated into a voltage-gated ion channel, and the absorption and emission spectra of the luciferine/luciferase complex. These examples show that the toolkit can be employed in a manifold of situations for both the electronic ground state and electronically excited states. It also allows for the automatic correction of the active space in the case of CASSCF calculations on an ensemble of geometries, as it is shown for the azobenzene derivative photoswitch case.
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Affiliation(s)
- Gustavo Cárdenas
- Department of ChemistryUniversidad Autónoma de MadridMadridSpain
| | | | | | | | | | - Lorena Ruano
- Department of ChemistryUniversidad Autónoma de MadridMadridSpain
| | | | - Sergio Díaz‐Tendero
- Department of ChemistryUniversidad Autónoma de MadridMadridSpain
- Institute for Advanced Research in Chemistry (IAdChem)Universidad Autónoma de MadridMadridSpain
- Condensed Matter Physics Center (IFIMAC)Universidad Autónoma de MadridMadridSpain
| | - Marcos Mandado
- Department of Physical ChemistryUniversity of VigoVigoSpain
| | - Juan J. Nogueira
- Department of ChemistryUniversidad Autónoma de MadridMadridSpain
- Institute for Advanced Research in Chemistry (IAdChem)Universidad Autónoma de MadridMadridSpain
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6
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Zlobin A, Belyaeva J, Golovin A. Challenges in Protein QM/MM Simulations with Intra-Backbone Link Atoms. J Chem Inf Model 2023; 63:546-560. [PMID: 36633836 DOI: 10.1021/acs.jcim.2c01071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hybrid quantum mechanical/molecular mechanical (QM/MM) simulations fuel discoveries in many fields of science including computational biochemistry and enzymology. Development of more convenient tools leads to an increase in the number of works in which mechanical insights into enzymes' mode of operation are obtained. Most commonly, these tools feature hydrogen-capping (link atom) approach to provide coupling between QM and MM subsystems across a covalent bond. Extensive studies were conducted to provide a solid foundation for the correctness of such an approach when a bond to a nonpolar MM atom is considered. However, not every task may be accomplished this way. Certain scenarios of using QM/MM in computational enzymology encourage or even necessitate the incorporation of backbone atoms into the QM region. Two out of three backbone atoms are polar, and in QM/MM with electrostatic embedding, a neighboring link atom will be hyperpolarized. Several schemes to mitigate this effect were previously proposed alongside a rigorous assessment of quantitative effects on model systems. However, it was not clear whether they may translate into qualitatively different results and how link atom hyperpolarization may manifest itself in a real-life enzymological scenario. Here, we show that the consequences of such an artifact may be severe and may completely overturn the conclusions drawn from the simulations. Our case advocates for the use of charge redistribution schemes whenever intra-backbone QM/MM boundaries are considered. Moreover, we addressed how different boundary types and charge redistribution schemes influence backbone dynamics. We showed that the results are heavily dependent on which boundary MM terms are retained, with charge alteration being of secondary importance. In the worst case, only three intra-backbone boundaries may be used with relative confidence in the adequacy of resulting simulations, irrespective of the hyperpolarization mitigation scheme. Thus, advances in the field are certainly needed to fuel new discoveries. As of now, we believe that issues raised in this work might encourage authors in the field to report what boundaries, boundary MM terms, and charge redistribution schemes they are using, so their results may be correctly interpreted.
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Affiliation(s)
- Alexander Zlobin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
| | - Julia Belyaeva
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Andrey Golovin
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 117997 Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, 119991 Moscow, Russia
- Sirius University of Science and Technology, 354340 Sochi, Russia
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7
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Field MJ. pDynamo3 Molecular Modeling and Simulation Program. J Chem Inf Model 2022; 62:5849-5854. [PMID: 36449463 DOI: 10.1021/acs.jcim.2c01239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
pDynamo3 is the first formal version of the Dynamo molecular modeling and simulation library that is written in Python 3. It follows from the previous pDynamo versions written in Python 2, the first of which was released in 2007. Both pDynamo and its predecessor, fDynamo, were designed with the aim of providing easy-to-use and flexible frameworks for performing molecular simulations at an atomistic level with a special emphasis on those employing hybrid quantum chemical and molecular mechanical potential methods. Although the use of pDynamo3 is quite similar to that of pDynamo2, it has added significant new capability and also undergone extensive restructuring that will make it much easier to extend with new functionality. The pDynamo3 code is issued under the GNU general public license at https://github.com/pdynamo/pDynamo3 with additional information on the pDynamo website https:www.pdynamo.org.
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Affiliation(s)
- Martin J Field
- Laboratoire de Chimie et Biologie des Métaux, UMR5249, Université Grenoble I, CEA, CNRS, 17 avenue des Martyrs, 38054 Cedex 9, Grenoble, France.,Theory Group, Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Cedex 9, Grenoble, France
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8
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Abstract
Density fitting is a standard technique in quantum chemistry as it helps to accelerate certain parts of a calculation, such as the computation of the electron repulsion energy, without significant loss of accuracy. This paper explores the effectiveness of this technique when it is extended to treat interactions with external electrostatic potentials, in particular those that arise from the environment in hybrid quantum chemical/molecular mechanical calculations. It is found that fitted densities are able to well reproduce the energies, forces, and properties obtained using unfitted densities, as long as a suitable operator is employed for the fitting. It is expected that this precision would be improved by the development of basis sets specifically designed to treat these types of interactions and that the use of this approximation could lead to substantial speed-ups in large hybrid potential simulations.
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Affiliation(s)
- Martin J Field
- Laboratoire de Chimie et Biologie des Métaux, UMR5249, Université Grenoble I, CEA, CNRS, 17 avenue des Martyrs, 38054 Cedex 9, Grenoble, France.,Theory Group, Institut Laue-Langevin, 71 avenue des Martyrs CS 20156, 38042 Cedex 9, Grenoble, France
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9
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Menezes F, Popowicz GM. ULYSSES: An Efficient and Easy to Use Semiempirical Library for C+. J Chem Inf Model 2022; 62:3685-3694. [PMID: 35930308 DOI: 10.1021/acs.jcim.2c00757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We introduce ULYSSES, a user-friendly and robust C++ library for semiempirical quantum chemical calculations. In its current version, ULYSSES is equipped with a large set of different semiempirical models, most of which are based on the Neglect of Diatomic Differential Overlap (NDDO) approximation. Empirical corrections for dispersion and hydrogen bonding are available for most methods, so that higher quality is achieved in the calculation of energies of nonbonded complexes. The library is furthermore equipped with geometry optimization, as well as modules for calculating molecular properties of general interest. Ideal gas thermodynamics is available and allows single structure as well as conformer (multistructure) averaged properties to be calculated. We offer the possibility to use several vibrational partition functions according to the nature of interactions being studied: for covalent systems, the traditional harmonic oscillator approximation is available; for nonbonded complexes, we systematically extended the partition function proposed by Grimme for all thermodynamic functions. The library is also capable of running Born-Oppenheimer molecular dynamics.
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Affiliation(s)
- Filipe Menezes
- Institute of Structural Biology, Helmholtz Zentrum Muenchen, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Grzegorz M Popowicz
- Institute of Structural Biology, Helmholtz Zentrum Muenchen, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
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10
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Zhuang B, Vos MH, Aleksandrov A. Photochemical and Molecular Dynamics Studies of Halide Binding in Flavoenzyme Glucose Oxidase. Chembiochem 2022; 23:e202200227. [PMID: 35876386 DOI: 10.1002/cbic.202200227] [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: 04/20/2022] [Revised: 07/11/2022] [Indexed: 11/11/2022]
Abstract
Glucose oxidase (GOX), a characteristic flavoprotein oxidase with widespread industrial applications, binds fluoride (F - ) and chloride (Cl - ). We investigated binding properties of halide inhibitors of GOX through time-resolved spectral characterization of flavin-related photochemical processes and molecular dynamic simulations. Cl - and F - bind differently to the protein active site and have substantial but opposite effects on the population and decay of the flavin excited state. Cl - binds closer to the flavin, whose excited-state decays in <100 fs due to anion-π interactions. Such interactions appear absent in F - binding, which, however, significantly increases the active-site rigidity leading to more homogeneous, picosecond fluorescence decay kinetics. These findings are discussed in relation to the mechanism of halide inhibition of GOX by occupying the accommodation site of catalytic intermediates and increasing the active-site rigidity.
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Affiliation(s)
- Bo Zhuang
- Ecole Polytechnique, LOB, CNRS, INSERM, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, FRANCE
| | - Marten H Vos
- CNRS UMR7645, Laboratory of Optics and Biosciences, CNRS, INSERM, École Polytechnique, Institut Polytechnique de Paris, 91128, Palaiseau, FRANCE
| | - Alexey Aleksandrov
- Ecole Polytechnique, Laboratory of Optics and Biosciences, Department of Biology, rue du Saclay, 91128, Palaiseau, FRANCE
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11
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Gisdon FJ, Bombarda E, Ullmann GM. Serine and Cysteine Peptidases: So Similar, Yet Different. How the Active-Site Electrostatics Facilitates Different Reaction Mechanisms. J Phys Chem B 2022; 126:4035-4048. [PMID: 35609250 DOI: 10.1021/acs.jpcb.2c01484] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The catalytic mechanisms of serine and cysteine peptidases are similar: the proton of the nucleophile (serine or cysteine) is transferred to the catalytic histidine, and the nucleophile attacks the substrate for cleavage. However, they differ in an important aspect: cysteine peptidases form a stable ion-pair intermediate in a stepwise mechanism, while serine peptidases follow a concerted mechanism. While it is known that a positive electrostatic potential at the active site of cysteine peptidases stabilizes the cysteine anion in the ion-pair state, the physical basis of the concerted mechanism of serine peptidases is poorly understood. In this work, we use continuum electrostatic analysis and quantum mechanical/molecular mechanical (QM/MM) simulations to demonstrate that a destabilization of an anionic serine by a negative electrostatic potential in combination with a compact active site geometry facilitates a concerted mechanism in serine peptidases. Moreover, we show that an anionic serine would destabilize the protein significantly compared to an anionic cysteine in cysteine peptidases, which underlines the necessity of a concerted mechanism for serine peptidases. On the basis of our calculations on an inactive serine mutant of a natural cysteine peptidase, we show that the energy barrier for the catalytic mechanism can be substantially decreased by introducing a negative electrostatic potential and by reducing the relevant distances indicating that these parameters are essential for the activity of serine peptidases. Our work demonstrates that the concerted mechanism of serine peptidases represents an evolutionary innovative way to perform catalysis without the energetically expensive need to stabilize the anionic serine. In contrast in cysteine peptidases, the anionic cysteine is energetically easily accessible and it is a very efficient nucleophile, making these peptidases mechanistically simple. However, a cysteine is highly oxygen sensitive, which is problematic in an aerobic environment. On the basis of the analysis in this work, we suggest that serine peptidases represent an oxygen-insensitive alternative to cysteine peptidases.
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Affiliation(s)
- Florian J Gisdon
- Biochemistry, University of Bayreuth, Universitätsstraße 30, BGI, 95447 Bayreuth, Germany.,Computational Biochemistry, University of Bayreuth, Universitätsstraße 30, BGI, 95447 Bayreuth, Germany
| | - Elisa Bombarda
- Computational Biochemistry, University of Bayreuth, Universitätsstraße 30, BGI, 95447 Bayreuth, Germany
| | - G Matthias Ullmann
- Computational Biochemistry, University of Bayreuth, Universitätsstraße 30, BGI, 95447 Bayreuth, Germany
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12
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Gisdon FJ, Feiler CG, Kempf O, Foerster JM, Haiss J, Blankenfeldt W, Ullmann GM, Bombarda E. Structural and Biophysical Analysis of the Phytochelatin-Synthase-Like Enzyme from Nostoc sp. Shows That Its Protease Activity is Sensitive to the Redox State of the Substrate. ACS Chem Biol 2022; 17:883-897. [PMID: 35377603 DOI: 10.1021/acschembio.1c00941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phytochelatins (PCs) are nonribosomal thiol-rich oligopeptides synthetized from glutathione (GSH) in a γ-glutamylcysteinyl transpeptidation reaction catalyzed by PC synthases (PCSs). Ubiquitous in plant and present in some invertebrates, PCSs are involved in metal detoxification and homeostasis. The PCS-like enzyme from the cyanobacterium Nostoc sp. (NsPCS) is considered to be an evolutionary precursor enzyme of genuine PCSs because it shows sufficient sequence similarity for homology to the catalytic domain of the eukaryotic PCSs and shares the peptidase activity consisting in the deglycination of GSH. In this work, we investigate the catalytic mechanism of NsPCS by combining structural, spectroscopic, thermodynamic, and theoretical techniques. We report several crystal structures of NsPCS capturing different states of the catalyzed chemical reaction: (i) the structure of the wild-type enzyme (wt-NsPCS); (ii) the high-resolution structure of the γ-glutamyl-cysteine acyl-enzyme intermediate (acyl-NsPCS); and (iii) the structure of an inactive variant of NsPCS, with the catalytic cysteine mutated into serine (C70S-NsPCS). We characterize NsPCS as a relatively slow enzyme whose activity is sensitive to the redox state of the substrate. Namely, NsPCS is active with reduced glutathione (GSH), but is inhibited by oxidized glutathione (GSSG) because the cleavage product is not released from the enzyme. Our biophysical analysis led us to suggest that the biological function of NsPCS is being a part of a redox sensing system. In addition, we propose a mechanism how PCS-like enzymes may have evolved toward genuine PCS enzymes.
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Affiliation(s)
- Florian J. Gisdon
- Department of Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
- Computational Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
| | - Christian G. Feiler
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
| | - Oxana Kempf
- Department of Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
| | - Johannes M. Foerster
- Computational Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
| | - Jonathan Haiss
- Department of Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
| | - Wulf Blankenfeldt
- Department Structure and Function of Proteins, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124 Braunschweig, Germany
- Institute for Biochemistry, Biotechnology and Bioinformatics, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany
| | - G. Matthias Ullmann
- Computational Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
| | - Elisa Bombarda
- Department of Biochemistry, University of Bayreuth, Universitätsstr. 30, 95440 Bayreuth, Germany
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13
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Ultrafast photooxidation of protein-bound anionic flavin radicals. Proc Natl Acad Sci U S A 2022; 119:2118924119. [PMID: 35181610 PMCID: PMC8872763 DOI: 10.1073/pnas.2118924119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2022] [Indexed: 12/17/2022] Open
Abstract
Flavoproteins are colored proteins involved in a large variety of biochemical reactions. They can perform photochemical reactions, which are increasingly exploited for bioengineering new protein-derived photocatalysts. In particular, light-induced reduction of the resting oxidized state of the flavin by close-lying amino acids or substrates is extensively studied. Here, we demonstrate that the reverse and previously unknown reaction photooxidation of the anionic semireduced flavin radical, a short-lived reaction intermediate in many biochemical reactions, efficiently occurs in flavoprotein oxidases. We anticipate that this finding will allow photoreduction of external reactants and lead to exploration of novel photocatalytic pathways. The photophysical properties of anionic semireduced flavin radicals are largely unknown despite their importance in numerous biochemical reactions. Here, we studied the photoproducts of these intrinsically unstable species in five different flavoprotein oxidases where they can be stabilized, including the well-characterized glucose oxidase. Using ultrafast absorption and fluorescence spectroscopy, we unexpectedly found that photoexcitation systematically results in the oxidation of protein-bound anionic flavin radicals on a time scale of less than ∼100 fs. The thus generated photoproducts decay back in the remarkably narrow 10- to 20-ps time range. Based on molecular dynamics and quantum mechanics computations, positively charged active-site histidine and arginine residues are proposed to be the electron acceptor candidates. Altogether, we established that, in addition to the commonly known and extensively studied photoreduction of oxidized flavins in flavoproteins, the reverse process (i.e., the photooxidation of anionic flavin radicals) can also occur. We propose that this process may constitute an excited-state deactivation pathway for protein-bound anionic flavin radicals in general. This hitherto undocumented photochemical reaction in flavoproteins further extends the family of flavin photocycles.
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14
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Yuan G, Curtolo F, Deng Y, Wu T, Tian F, Ma Q, Liu Y, Zuo J, Arantes GM, Zheng P. Highly Dynamic Polynuclear Metal Cluster Revealed in a Single Metallothionein Molecule. RESEARCH 2021; 2021:9756945. [PMID: 34368766 PMCID: PMC8299258 DOI: 10.34133/2021/9756945] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/04/2021] [Indexed: 11/06/2022]
Abstract
Human metallothionein (MT) is a small-size yet efficient metal-binding protein, playing an essential role in metal homeostasis and heavy metal detoxification. MT contains two domains, each forming a polynuclear metal cluster with an exquisite hexatomic ring structure. The apoprotein is intrinsically disordered, which may strongly influence the clusters and the metal-thiolate (M-S) bonds, leading to a highly dynamic structure. However, these features are challenging to identify due to the transient nature of these species. The individual signal from dynamic conformations with different states of the cluster and M-S bond will be averaged and blurred in classic ensemble measurement. To circumvent these problems, we combined a single-molecule approach and multiscale molecular simulations to investigate the rupture mechanism and chemical stability of the metal cluster by a single MT molecule, focusing on the Zn4S11 cluster in the α domain upon unfolding. Unusual multiple unfolding pathways and intermediates are observed for both domains, corresponding to different combinations of M-S bond rupture. None of the pathways is clearly preferred suggesting that unfolding proceeds from the distribution of protein conformational substates with similar M-S bond strengths. Simulations indicate that the metal cluster may rearrange, forming and breaking metal-thiolate bonds even when MT is folded independently of large protein backbone reconfiguration. Thus, a highly dynamic polynuclear metal cluster with multiple conformational states is revealed in MT, responsible for the binding promiscuity and diverse cellular functions of this metal-carrier protein.
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Affiliation(s)
- Guodong Yuan
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Felipe Curtolo
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-900 São Paulo, SP, Brazil
| | - Yibing Deng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Tao Wu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Fang Tian
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Qun Ma
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Yutong Liu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Jinglin Zuo
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Guilherme Menegon Arantes
- Department of Biochemistry, Instituto de Química, Universidade de São Paulo, Av. Prof. Lineu Prestes 748, 05508-900 São Paulo, SP, Brazil
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, Jiangsu 210023, China
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15
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Peralta FA, Huidobro-Toro JP, Mera-Adasme R. Hybrid QM/MM Simulations Confirm Zn(II) Coordination Sphere That Includes Four Cysteines from the P2 × 4R Head Domain. Int J Mol Sci 2021; 22:ijms22147288. [PMID: 34298909 PMCID: PMC8303255 DOI: 10.3390/ijms22147288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 11/21/2022] Open
Abstract
To ascertain the role of Zn(II) as an allosteric modulator on P2X4R, QM/MM molecular dynamic simulations were performed on the WT and two P2X4R mutants suggested by previous electrophysiological data to affect Zn(II) binding. The Gibbs free energy for the reduction of the putative P2X4R Zn(II) binding site by glutathione was estimated at −22 kcal/mol. Simulations of the WT P2X4R head domain revealed a flexible coordination sphere dominated by an octahedral geometry encompassing C126, N127, C132, C149, C159 and a water molecule. The C132A mutation disrupted the metal binding site, leading to a coordination sphere with a majority of water ligands, and a displacement of the metal ion towards the solvent. The C132A/C159A mutant exhibited a tendency towards WT-like stability by incorporating the R148 backbone to the coordination sphere. Thus, the computational findings agree with previous experimental data showing Zn(II) modulation for the WT and C132A/C159A variants, but not for the C132A mutant. The results provide molecular insights into the nature of the Zn(II) modulation in P2X4R, and the effect of the C132A and C132A/C159A mutations, accounting for an elusive modulation mechanism possibly occurring in other extracellular or membrane protein.
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Affiliation(s)
| | - J. Pablo Huidobro-Toro
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile
- Centro Para el Desarrollo de Nanociencia y Nanotecnología, (CEDENNA), Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile
- Correspondence: (J.P.H.-T.); (R.M.-A.)
| | - Raúl Mera-Adasme
- Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Santiago 9170124, Chile
- Correspondence: (J.P.H.-T.); (R.M.-A.)
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16
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Wan Q, Bennett BC, Wymore T, Li Z, Wilson MA, Brooks CL, Langan P, Kovalevsky A, Dealwis CG. Capturing the Catalytic Proton of Dihydrofolate Reductase: Implications for General Acid-Base Catalysis. ACS Catal 2021; 11:5873-5884. [PMID: 34055457 PMCID: PMC8154319 DOI: 10.1021/acscatal.1c00417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/19/2021] [Indexed: 02/04/2023]
Abstract
![]()
Acid–base
catalysis, which involves one or more proton transfer
reactions, is a chemical mechanism commonly employed by many enzymes.
The molecular basis for catalysis is often derived from structures
determined at the optimal pH for enzyme activity. However, direct
observation of protons from experimental structures is quite difficult;
thus, a complete mechanistic description for most enzymes remains
lacking. Dihydrofolate reductase (DHFR) exemplifies general acid–base
catalysis, requiring hydride transfer and protonation of its substrate,
DHF, to form the product, tetrahydrofolate (THF). Previous X-ray and
neutron crystal structures coupled with theoretical calculations have
proposed that solvent mediates the protonation step. However, visualization
of a proton transfer has been elusive. Based on a 2.1 Å resolution
neutron structure of a pseudo-Michaelis complex of E. coli DHFR determined at acidic pH, we report the
direct observation of the catalytic proton and its parent solvent
molecule. Comparison of X-ray and neutron structures elucidated at
acidic and neutral pH reveals dampened dynamics at acidic pH, even
for the regulatory Met20 loop. Guided by the structures and calculations,
we propose a mechanism where dynamics are crucial for solvent entry
and protonation of substrate. This mechanism invokes the release of
a sole proton from a hydronium (H3O+) ion, its
pathway through a narrow channel that sterically hinders the passage
of water, and the ultimate protonation of DHF at the N5 atom.
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Affiliation(s)
| | - Brad C. Bennett
- Biological and Environmental Science Department, Samford University, Birmingham, Alabama 35229, United States
| | - Troy Wymore
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Mark A. Wilson
- Department of Biochemistry and Redox Biology Center, University of Nebraska, Lincoln, Nebraska 68588, United States
| | - Charles L. Brooks
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Paul Langan
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, United States
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17
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Martí S. QMCube (QM 3 ): An all-purpose suite for multiscale QM/MM calculations. J Comput Chem 2021; 42:447-457. [PMID: 33337551 DOI: 10.1002/jcc.26465] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/03/2020] [Accepted: 11/26/2020] [Indexed: 12/16/2022]
Abstract
QMCube (QM3 ) is a suite written in the Python programming language, initially focused on multiscale QM/MM simulations of biological systems, but open enough to address other kinds of problems. It allows the user to combine highly efficient QM and MM programs, providing unified access to a wide range of computational methods. The suite also supplies additional modules with extra functionalities. These modules facilitate common tasks such as performing the setup of the models or process the data generated during the simulations. The design of QM3 has been carried out considering the least number of external dependencies (only an algebra library, already included in the distribution), which makes it extremely portable. Also, the modular structure of the suite should help to expand and develop new computational methods.
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Affiliation(s)
- Sergio Martí
- Departament de Química Física i Analítica, Universitat Jaume I, Castellón, Spain
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18
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Zhuang B, Seo D, Aleksandrov A, Vos MH. Characterization of Light-Induced, Short-Lived Interacting Radicals in the Active Site of Flavoprotein Ferredoxin-NADP + Oxidoreductase. J Am Chem Soc 2021; 143:2757-2768. [PMID: 33591179 DOI: 10.1021/jacs.0c09627] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Radicals of flavin adenine dinucleotide (FAD), as well as tyrosine and tryptophan, are widely involved as key reactive intermediates during electron-transfer (ET) reactions in flavoproteins. Due to the high reactivity of these species and their corresponding short lifetime, characterization of these intermediates in functional processes of flavoproteins is usually challenging but can be achieved by ultrafast spectroscopic studies of light-activatable flavoproteins. In ferredoxin-NADP+ oxidoreductase from Bacillus subtilis (BsFNR), fluorescence of the FAD cofactor that very closely interacts with a neighboring tyrosine residue (Tyr50) is strongly quenched. Here we study short-lived photoproducts of this enzyme and its variants, with Tyr50 replaced by tryptophan or glycine. Using time-resolved fluorescence and absorption spectroscopies, we show that, upon the excitation of WT BsFNR, ultrafast ET from Tyr50 to the excited FAD cofactor occurs in ∼260 fs, an order of magnitude faster than the decay by charge recombination, facilitating the characterization of the reaction intermediates in the charge-separated state with respect to other recently studied systems. These studies are corroborated by experiments on the Y50W mutant protein, which yield photoproducts qualitatively similar to those observed in other tryptophan-bearing flavoproteins. By combining the experimental results with molecular dynamics simulations and quantum mechanics calculations, we investigate in detail the effects of protein environment and relaxations on the spectral properties of those radical intermediates and demonstrate that the spectral features of radical anionic FAD are highly sensitive to its environment, and in particular to the dynamics and nature of the counterions formed in the photoproducts. Altogether, comprehensive characterizations are provided for important radical intermediates that are generally involved in functional processes of flavoproteins.
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Affiliation(s)
- Bo Zhuang
- LOB, CNRS, INSERM, École Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Daisuke Seo
- Division of Material Science, Graduate School of Natural Science and Technology, Kanazawa University, 920-1192 Kanazawa, Ishikawa, Japan
| | - Alexey Aleksandrov
- LOB, CNRS, INSERM, École Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France
| | - Marten H Vos
- LOB, CNRS, INSERM, École Polytechnique, Institut Polytechnique de Paris, 91128 Palaiseau, France
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19
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Milo S, Heylen RA, Glancy J, Williams GT, Patenall BL, Hathaway HJ, Thet NT, Allinson SL, Laabei M, Jenkins ATA. A small-molecular inhibitor against Proteus mirabilis urease to treat catheter-associated urinary tract infections. Sci Rep 2021; 11:3726. [PMID: 33580163 PMCID: PMC7881204 DOI: 10.1038/s41598-021-83257-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/26/2021] [Indexed: 01/30/2023] Open
Abstract
Infection and blockage of indwelling urinary catheters is significant owing to its high incidence rate and severe medical consequences. Bacterial enzymes are employed as targets for small molecular intervention in human bacterial infections. Urease is a metalloenzyme known to play a crucial role in the pathogenesis and virulence of catheter-associated Proteus mirabilis infection. Targeting urease as a therapeutic candidate facilitates the disarming of bacterial virulence without affecting bacterial fitness, thereby limiting the selective pressure placed on the invading population and lowering the rate at which it will acquire resistance. We describe the design, synthesis, and in vitro evaluation of the small molecular enzyme inhibitor 2-mercaptoacetamide (2-MA), which can prevent encrustation and blockage of urinary catheters in a physiologically representative in vitro model of the catheterized urinary tract. 2-MA is a structural analogue of urea, showing promising competitive activity against urease. In silico docking experiments demonstrated 2-MA's competitive inhibition, whilst further quantum level modelling suggests two possible binding mechanisms.
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Affiliation(s)
- Scarlet Milo
- grid.7340.00000 0001 2162 1699Department of Chemistry, University of Bath, Bath, BA2 7AY UK
| | - Rachel A. Heylen
- grid.7340.00000 0001 2162 1699Department of Chemistry, University of Bath, Bath, BA2 7AY UK
| | - John Glancy
- grid.7340.00000 0001 2162 1699Department of Chemistry, University of Bath, Bath, BA2 7AY UK
| | - George T. Williams
- grid.9759.20000 0001 2232 2818School of Physical Sciences, University of Kent, Canterbury, CT2 7NH UK
| | - Bethany L. Patenall
- grid.7340.00000 0001 2162 1699Department of Chemistry, University of Bath, Bath, BA2 7AY UK
| | - Hollie J. Hathaway
- grid.9835.70000 0000 8190 6402Department of Chemistry, Lancaster University, Bailrigg, Lancaster, LA1 4YB UK
| | - Naing T. Thet
- grid.7340.00000 0001 2162 1699Department of Chemistry, University of Bath, Bath, BA2 7AY UK
| | - Sarah L. Allinson
- grid.9835.70000 0000 8190 6402Biomedical and Life Sciences Division, Lancaster University, Bailrigg, Lancaster, LA1 4YB UK
| | - Maisem Laabei
- grid.7340.00000 0001 2162 1699Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY UK
| | - A. Toby A. Jenkins
- grid.7340.00000 0001 2162 1699Department of Chemistry, University of Bath, Bath, BA2 7AY UK
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20
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Kehrer J, Richter R, Foerster JM, Schelter I, Kümmel S. Self-interaction correction, electrostatic, and structural influences on time-dependent density functional theory excitations of bacteriochlorophylls from the light-harvesting complex 2. J Chem Phys 2020; 153:144114. [PMID: 33086803 DOI: 10.1063/5.0014938] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
First-principles calculations offer the chance to obtain a microscopic understanding of light-harvesting processes. Time-dependent density functional theory can have the computational efficiency to allow for such calculations. However, the (semi-)local exchange-correlation approximations that are computationally most efficient fail to describe charge-transfer excitations reliably. We here investigate whether the inexpensive average density self-interaction correction (ADSIC) remedies the problem. For the systems that we study, ADSIC is even more prone to the charge-transfer problem than the local density approximation. We further explore the recently reported finding that the electrostatic potential associated with the chromophores' protein environment in the light-harvesting complex 2 beneficially shifts spurious excitations. We find a great sensitivity on the chromophores' atomistic structure in this problem. Geometries obtained from classical molecular dynamics are more strongly affected by the spurious charge-transfer problem than the ones obtained from crystallography or density functional theory. For crystal structure geometries and density-functional theory optimized ones, our calculations confirm that the electrostatic potential shifts the spurious excitations out of the energetic range that is most relevant for electronic coupling.
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Affiliation(s)
- Juliana Kehrer
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
| | - Rian Richter
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
| | | | - Ingo Schelter
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
| | - Stephan Kümmel
- Theoretical Physics IV, University of Bayreuth, D-95440 Bayreuth, Germany
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21
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Theoretical characterization of the shikimate 5-dehydrogenase reaction from Mycobacterium tuberculosis by hybrid QC/MM simulations and quantum chemical descriptors. J Mol Model 2020; 26:297. [PMID: 33030705 DOI: 10.1007/s00894-020-04536-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 09/07/2020] [Indexed: 11/27/2022]
Abstract
In this study, we have investigated the enzyme shikimate 5-dehydrogenase from the causative agent of tuberculosis, Mycobacterium tuberculosis. We have employed a mixture of computational techniques, including molecular dynamics, hybrid quantum chemical/molecular mechanical potentials, relaxed surface scans, quantum chemical descriptors and free-energy simulations, to elucidate the enzyme's reaction pathway. Overall, we find a two-step mechanism, with a single transition state, that proceeds by an energetically uphill hydride transfer, followed by an energetically downhill proton transfer. Our mechanism and calculated free energy barrier for the reaction, 64.9 kJ mol- 1, are in good agreement with those predicted from experiment. An analysis of quantum chemical descriptors along the reaction pathway indicated a possibly important, yet currently unreported, role of the active site threonine residue, Thr65.
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22
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Zhang Y, Suo B, Wang Z, Zhang N, Li Z, Lei Y, Zou W, Gao J, Peng D, Pu Z, Xiao Y, Sun Q, Wang F, Ma Y, Wang X, Guo Y, Liu W. BDF: A relativistic electronic structure program package. J Chem Phys 2020; 152:064113. [DOI: 10.1063/1.5143173] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Yong Zhang
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
| | - Bingbing Suo
- Shaanxi Key Laboratory for Theoretical Physics Frontiers, Institute of Modern Physics, Northwest University, Xi’an, Shaanxi 710127, People’s Republic of China
| | - Zikuan Wang
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing 100871, People’s Republic of China
| | - Ning Zhang
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing 100871, People’s Republic of China
| | - Zhendong Li
- Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875, People’s Republic of China
| | - Yibo Lei
- Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Shaanxi Key Laboratory of Physico-Inorganic Chemistry, College of Chemistry and Materials Science, Northwest University, Xi’an, Shaanxi 710127, People’s Republic of China
| | - Wenli Zou
- Shaanxi Key Laboratory for Theoretical Physics Frontiers, Institute of Modern Physics, Northwest University, Xi’an, Shaanxi 710127, People’s Republic of China
| | - Jun Gao
- Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, Wuhan, Hubei 430070, People’s Republic of China
| | - Daoling Peng
- College of Chemistry, South China Normal University, Guangzhou, Guangdong 510006, People’s Republic of China
| | - Zhichen Pu
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing 100871, People’s Republic of China
| | - Yunlong Xiao
- Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, College of Chemistry and Molecular Engineering, Beijing 100871, People’s Republic of China
| | - Qiming Sun
- Tencent America LLC, Palo Alto, California 94306, USA
| | - Fan Wang
- Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, People’s Republic of China
| | - Yongtao Ma
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
| | - Xiaopeng Wang
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
| | - Yang Guo
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
| | - Wenjian Liu
- Qingdao Institute for Theoretical and Computational Sciences, Shandong University, Qingdao, Shandong 266237, People’s Republic of China
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23
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da Costa CHS, Bonatto V, Dos Santos AM, Lameira J, Leitão A, Montanari CA. Evaluating QM/MM Free Energy Surfaces for Ranking Cysteine Protease Covalent Inhibitors. J Chem Inf Model 2020; 60:880-889. [PMID: 31944110 DOI: 10.1021/acs.jcim.9b00847] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
One tactic for cysteine protease inhibition is to form a covalent bond between an electrophilic atom of the inhibitor and the thiol of the catalytic cysteine. In this study, we evaluate the reaction free energy obtained from a hybrid quantum mechanical/molecular mechanical (QM/MM) free energy profile as a predictor of affinity for reversible, covalent inhibitors of rhodesain. We demonstrate that the reaction free energy calculated with the PM6/MM potential is in agreement with the experimental data and suggest that the free energy profile for covalent bond formation in a protein environment may be a useful tool for the inhibitor design.
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Affiliation(s)
- Clauber H S da Costa
- Laboratório de Planejamento e Desenvolvimento de Fármacos , Universidade Federal do Pará , Rua Augusto Correa S/N , 66075-110 Belém , PA , Brazil
| | - Vinícius Bonatto
- Grupo de Quı́mica Medicinal do Instituto de Quı́mica de São Carlos da , Universidade de São Paulo, NEQUIMED/IQSC/USP , 13566-590 São Carlos , SP , Brazil
| | - Alberto M Dos Santos
- Laboratório de Planejamento e Desenvolvimento de Fármacos , Universidade Federal do Pará , Rua Augusto Correa S/N , 66075-110 Belém , PA , Brazil
| | - Jerônimo Lameira
- Laboratório de Planejamento e Desenvolvimento de Fármacos , Universidade Federal do Pará , Rua Augusto Correa S/N , 66075-110 Belém , PA , Brazil.,Grupo de Quı́mica Medicinal do Instituto de Quı́mica de São Carlos da , Universidade de São Paulo, NEQUIMED/IQSC/USP , 13566-590 São Carlos , SP , Brazil
| | - Andrei Leitão
- Grupo de Quı́mica Medicinal do Instituto de Quı́mica de São Carlos da , Universidade de São Paulo, NEQUIMED/IQSC/USP , 13566-590 São Carlos , SP , Brazil
| | - Carlos A Montanari
- Grupo de Quı́mica Medicinal do Instituto de Quı́mica de São Carlos da , Universidade de São Paulo, NEQUIMED/IQSC/USP , 13566-590 São Carlos , SP , Brazil
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24
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Grillo IB, Urquiza-Carvalho GA, Bachega JFR, Rocha GB. Elucidating Enzymatic Catalysis Using Fast Quantum Chemical Descriptors. J Chem Inf Model 2020; 60:578-591. [PMID: 31895567 DOI: 10.1021/acs.jcim.9b00860] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In general, computational simulations of enzymatic catalysis processes are thermodynamic and structural surveys to complement experimental studies, requiring high level computational methods to match accurate energy values. In the present work, we propose the usage of reactivity descriptors, theoretical quantities calculated from the electronic structure, to characterize enzymatic catalysis outlining its reaction profile using low-level computational methods, such as semiempirical Hamiltonians. We simulate three enzymatic reactions paths, one containing two reaction coordinates and without prior computational study performed, and calculate the reactivity descriptors for all obtained structures. We observed that the active site local hardness does not change substantially, even more so for the amino-acid residues that are said to stabilize the reaction structures. This corroborates with the theory that activation energy lowering is caused by the electrostatic environment of the active sites. Also, for the quantities describing the atom electrophilicity and nucleophilicity, we observed abrupt changes along the reaction coordinates, which also shows the enzyme participation as a reactant in the catalyzed reaction. We expect that such electronic structure analysis allows the expedient proposition and/or prediction of new mechanisms, providing chemical characterization of the enzyme active sites, thus hastening the process of transforming the resolved protein three-dimensional structures in catalytic information.
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Affiliation(s)
- Igor Barden Grillo
- Department of Chemistry , Federal University of Paraíba , Cidade Universitária, João Pessoa , Paraíba 58051-085 , Brazil
| | - Gabriel A Urquiza-Carvalho
- Department of Fundamental Chemistry , Federal University of Pernambuco , Cidade Universitária, Recife , Pernambuco 50670-901 , Brazil
| | - José Fernando Ruggiero Bachega
- Department of Pharmacosciences , Federal University of Health Sciences of Porto Alegre , Centro Histórico, Porto Alegre , Rio Grande do Sul 90050-170 , Brazil
| | - Gerd Bruno Rocha
- Department of Chemistry , Federal University of Paraíba , Cidade Universitária, João Pessoa , Paraíba 58051-085 , Brazil
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Herbst MF, Scheurer M, Fransson T, Rehn DR, Dreuw A. adcc: A versatile toolkit for rapid development of algebraic‐diagrammatic construction methods. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2020. [DOI: 10.1002/wcms.1462] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Michael F. Herbst
- CERMICS, École des Ponts ParisTech Marne‐la‐Vallée France
- Inria Paris Paris Cedex 12 France
- Sorbonne Université Institut des sciences du calcul et des données, ISCD Paris France
| | - Maximilian Scheurer
- Interdisciplinary Center for Scientific Computing Heidelberg University Heidelberg Germany
| | - Thomas Fransson
- Interdisciplinary Center for Scientific Computing Heidelberg University Heidelberg Germany
- Fysikum Stockholm University Stockholm Sweden
| | - Dirk R. Rehn
- Interdisciplinary Center for Scientific Computing Heidelberg University Heidelberg Germany
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing Heidelberg University Heidelberg Germany
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26
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Souza PT, Thallmair S, Marrink SJ, Mera-Adasme R. An Allosteric Pathway in Copper, Zinc Superoxide Dismutase Unravels the Molecular Mechanism of the G93A Amyotrophic Lateral Sclerosis-Linked Mutation. J Phys Chem Lett 2019; 10:7740-7744. [PMID: 31747286 PMCID: PMC6926953 DOI: 10.1021/acs.jpclett.9b02868] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 11/20/2019] [Indexed: 05/29/2023]
Abstract
Several different mutations of the protein copper, zinc superoxide dismutase (SOD1) produce the neurodegenerative disorder amyotrophic lateral sclerosis (ALS). The molecular mechanism by which the diverse mutations converge to a similar pathology is currently unknown. The electrostatic loop (EL) of SOD1 is known to be affected in all of the studied ALS-linked mutations of SOD1. In this work, we employ a multiscale simulation approach to show that this perturbation corresponds to an increased probability of the EL detaching from its native position, exposing the metal site of the protein to water. From extensive atomistic and coarse-grained molecular dynamics (MD) simulations, we identify an allosteric pathway that explains the action of the distant G93A mutation on the EL. Finally, we employ quantum mechanics/molecular mechanics MD simulations to show that the opening of the EL decreases the Zn(II) affinity of the protein. As the loss of Zn(II) is at the center of several proposed pathogenic mechanisms in SOD1-linked ALS, the structural effect identified here not only is in agreement with the experimental data but also places the opening of the electrostatic loop as the possible main pathogenic effect for a significant number of ALS-linked SOD1 mutations.
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Affiliation(s)
- Paulo
C. T. Souza
- Groningen
Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Sebastian Thallmair
- Groningen
Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Siewert J. Marrink
- Groningen
Biomolecular Sciences and Biotechnology Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Raúl Mera-Adasme
- Departamento
de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O’Higgins
3363, 9170022 Estacion
Central, Chile
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27
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Teixeira MH, Curtolo F, Camilo SRG, Field MJ, Zheng P, Li H, Arantes GM. Modeling the Hydrolysis of Iron-Sulfur Clusters. J Chem Inf Model 2019; 60:653-660. [PMID: 31790241 DOI: 10.1021/acs.jcim.9b00881] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Iron-sulfur (FeS) clusters are essential metal cofactors involved in a wide variety of biological functions. Their catalytic efficiency, biosynthesis, and regulation depend on FeS stability in aqueous solution. Here, molecular modeling is used to investigate the hydrolysis of an oxidized (ferric) mononuclear FeS cluster by bare dissociation and water substitution mechanisms in neutral and acidic solution. First, approximate electronic structure descriptions of FeS reactions by density functional theory are validated against high-level wave function CCSD(T) calculations. Solvation contributions are included by an all-atom model with hybrid quantum chemical/molecular mechanical (QM/MM) potentials and enhanced sampling molecular dynamics simulations. The free energy profile obtained for FeS cluster hydrolysis indicates that the hybrid functional M06 together with an implicit solvent correction capture the most important aspects of FeS cluster reactivity in aqueous solution. Then, 20 reaction channels leading to two consecutive Fe-S bond ruptures were explored with this calibrated model. For all protonation states, nucleophilic substitution with concerted bond breaking and forming to iron is the preferred mechanism, both kinetic and thermodynamically. In neutral solution, proton transfer from water to the sulfur leaving group is also concerted. Dissociative reactions show higher barriers and will not be relevant for FeS reactivity when exposed to solvent. These hydrolysis mechanisms may help to explain the stability and catalytic mechanisms of FeS clusters of multiple sizes and proteins.
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Affiliation(s)
- Murilo H Teixeira
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , SP , Brazil
| | - Felipe Curtolo
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , SP , Brazil
| | - Sofia R G Camilo
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , SP , Brazil
| | - Martin J Field
- CNRS, CEA, IRIG, Laboratoire de Chimie et Biologie des Métaux , Université Grenoble Alpes , 17 rue des Martyrs , 38000 Grenoble , France.,Institut Laue-Langevin , BP 156, 41 Avenue des Martyrs , 38042 Grenoble , Cedex 9, France
| | - Peng Zheng
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering , Nanjing University , Nanjing , Jiangsu 210023 , China
| | - Hongbin Li
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Guilherme M Arantes
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , SP , Brazil
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Rodriguez-Mackenzie AD, Arbelo-Lopez HD, Wymore T, Lopez-Garriga J. A reaction pathway to compound 0 intermediates in oxy-myoglobin through interactions with hydrogen sulfide and His64. J Mol Graph Model 2019; 94:107465. [PMID: 31670138 DOI: 10.1016/j.jmgm.2019.107465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/25/2019] [Accepted: 10/01/2019] [Indexed: 11/18/2022]
Abstract
Myoglobin (Mb) binds oxygen with high affinity as a low spin singlet complex and thus functions as an oxygen storage protein. Yet, hybrid Density Functional Theory/Molecular Mechanical (DFT/MM) calculations of oxy-Mb models predict that the O2 bond is much less resistant to breaking in the presence of hydrogen sulfide (H2S) compared with water. Specifically, a hydrogen atom from H2S can be transferred to the distal oxygen atom through homolytic cleavage of the S-H bond to form the intermediate Compound (Cpd) 0 structure and a thiyl radical. In the presence of a neutral His64 (Nε protonation, His64-ε) and H2S, only a metastable Cpd 0 would be formed as the active site is devoid of any additional proton donor to fully break the O2 bond. In contrast, the calculations predict that the triplet state is significantly favored over the open shell singlet diradical state throughout the entire reaction coordinate in the presence of H2S and a positively charged His64. Furthermore, a positively charged His64 can readily donate a proton to Cpd 0 to fully break the O2 bond resulting in a configuration analogous to reported reaction models of a hemoglobin mutant bound to H2O2 with H2S present. Typically, exotic techniques are required to generate Cpd 0 but under the conditions just described the intermediate is readily detected in UV-Vis spectra at room temperature. The effect is observed as a 2 nm red shift of the Soret band from 414 nm to 416 nm (pH 5.0, His64-εδ) and from 416 nm to 418 nm (pH 6.6, His64-ε).
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Affiliation(s)
| | - Hector D Arbelo-Lopez
- Department of Chemistry, University of Puerto Rico Mayaguez Campus, Mayaguez, 00680, Puerto Rico
| | - Troy Wymore
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109-1055, United States.
| | - Juan Lopez-Garriga
- Department of Chemistry, University of Puerto Rico Mayaguez Campus, Mayaguez, 00680, Puerto Rico.
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Tweedy SE, Rodríguez Benítez A, Narayan ARH, Zimmerman PM, Brooks CL, Wymore T. Hydroxyl Radical-Coupled Electron-Transfer Mechanism of Flavin-Dependent Hydroxylases. J Phys Chem B 2019; 123:8065-8073. [PMID: 31532200 DOI: 10.1021/acs.jpcb.9b08178] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Class A flavin-dependent hydroxylases (FdHs) catalyze the hydroxylation of organic compounds in a site- and stereoselective manner. In stark contrast, conventional synthetic routes require environmentally hazardous reagents and give modest yields. Thus, understanding the detailed mechanism of this class of enzymes is essential to their rational manipulation for applications in green chemistry and pharmaceutical production. Both electrophilic substitution and radical intermediate mechanisms have been proposed as interpretations of FdH hydroxylation rates and optical spectra. While radical mechanistic steps are often difficult to examine directly, modern quantum chemistry calculations combined with statistical mechanical approaches can yield detailed mechanistic models providing insights that can be used to differentiate reaction pathways. In the current work, we report quantum mechanical/molecular mechanical (QM/MM) calculations on the fungal TropB enzyme that shows an alternative reaction pathway in which hydroxylation through a hydroxyl radical-coupled electron-transfer mechanism is significantly favored over electrophilic substitution. Furthermore, QM/MM calculations on several modified flavins provide a more consistent interpretation of the experimental trends in the reaction rates seen experimentally for a related enzyme, para-hydroxybenzoate hydroxylase. These calculations should guide future enzyme and substrate design strategies and broaden the scope of biological spin chemistry.
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A comparison of computational methodologies for the structural modelling of biologically relevant zinc complexes. J Mol Model 2019; 25:258. [PMID: 31399760 DOI: 10.1007/s00894-019-4139-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 07/14/2019] [Indexed: 01/01/2023]
Abstract
The impact of a variety of modern computational methods on the structure of biologically relevant zinc complexes is studied. Different density functionals and a Hartree-Fock-based method, scalar-relativistic effects, and basis set integration grid choices, among others, are assessed for set of high-resolution crystallographic structures. While a previous study recommends incorporating relativistic effects into density functional theory calculations in order to improve the accuracy of obtained geometries for small Zn(II) coordination compounds, we show that, for the set in study, relativistic effects do not affect the geometries to a significant extent. The PBEh-3c composite method emerges as good alternative for the treatment of Zn(II) complexes, while the HF-3c method can be employed when computational efficiency is important. Graphical Abstract Which methods are best suited for the computation of Zn(II) bioligand complexes?
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31
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Hoias Teixeira M, Menegon Arantes G. Balanced internal hydration discriminates substrate binding to respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:541-548. [DOI: 10.1016/j.bbabio.2019.05.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 05/16/2019] [Accepted: 05/28/2019] [Indexed: 12/16/2022]
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Zhang B, Altarawy D, Barnes T, Turney JM, Schaefer HF. Janus: An Extensible Open-Source Software Package for Adaptive QM/MM Methods. J Chem Theory Comput 2019; 15:4362-4373. [DOI: 10.1021/acs.jctc.9b00182] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Boyi Zhang
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Doaa Altarawy
- The Molecular Sciences Software Institute, Virginia Tech, Blacksburg, Virginia 24060, United States
- Department of Computer and Systems Engineering, Alexandria University, Alexandria 21544, Egypt
| | - Taylor Barnes
- The Molecular Sciences Software Institute, Virginia Tech, Blacksburg, Virginia 24060, United States
| | - Justin M. Turney
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Henry F. Schaefer
- Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States
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A benchmark for the size of the QM system required for accurate hybrid QM/MM calculations on the metal site of the protein copper, zinc superoxide dismutase. J Mol Model 2019; 25:176. [PMID: 31154525 DOI: 10.1007/s00894-019-4066-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/14/2019] [Indexed: 12/12/2022]
Abstract
The protein superoxide dismutase 1 (SOD1) is a copper and zinc-binding protein that has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). The Zn(II) binding to SOD1 is critical for the stability of the protein, and has been by itself implicated in ALS pathogenesis. Hence, the quantum mechanical (QM) study of the Zn(II)-site of SOD1 is relevant for understanding ALS. The hybrid QM-molecular mechanics (QM/MM) approach commonly employed for the QM study of proteins is highly dependent on the size of the sub-system treated quantum-mechanically. The size of the QM system also determines the computational feasibility of a given method. In the present work, we compare optimized geometries for the metal site and Zn(II) dissociation energies obtained with a QM/MM methodology employing different sizes for the QM sub-system. We find that geometries converge rapidly to RMSDs of around 0.3 Å, and fails to converge further, while a QM system of 480 atoms was required for converging the Zn(II) interaction energy of SOD1 to within 5 kcal*mol-1, and a 611-atoms QM system for a 1 kcal*mol-1 convergence with respect to our reference, 1280 QM-atoms system. Graphical Abstract The size of the QM system is critical for both the accuracy and the computational cost of a QM/MM calculation. We have identified a optimum balance for the study of the active site of the coppper, zinc superoxide dismutase.
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Low potential enzymatic hydride transfer via highly cooperative and inversely functionalized flavin cofactors. Nat Commun 2019; 10:2074. [PMID: 31061390 PMCID: PMC6502838 DOI: 10.1038/s41467-019-10078-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 04/12/2019] [Indexed: 02/01/2023] Open
Abstract
Hydride transfers play a crucial role in a multitude of biological redox reactions and are mediated by flavin, deazaflavin or nicotinamide adenine dinucleotide cofactors at standard redox potentials ranging from 0 to –340 mV. 2-Naphthoyl-CoA reductase, a key enzyme of oxygen-independent bacterial naphthalene degradation, uses a low-potential one-electron donor for the two-electron dearomatization of its substrate below the redox limit of known biological hydride transfer processes at E°’ = −493 mV. Here we demonstrate by X-ray structural analyses, QM/MM computational studies, and multiple spectroscopy/activity based titrations that highly cooperative electron transfer (n = 3) from a low-potential one-electron (FAD) to a two-electron (FMN) transferring flavin cofactor is the key to overcome the resonance stabilized aromatic system by hydride transfer in a highly hydrophobic pocket. The results evidence how the protein environment inversely functionalizes two flavins to switch from low-potential one-electron to hydride transfer at the thermodynamic limit of flavin redox chemistry. The reduction of 2-naphtoyl-CoA to 5,6 dihydro-2-naphtoyl-CoA by 2-naphtoyl-CoA reductase is below the negative redox limit usually encountered in biological hydride transfer. Here, via X-ray crystallography and spectroscopic analysis, the authors elucidated the mechanism behind this.
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Cuyàs E, Verdura S, Lozano-Sánchez J, Viciano I, Llorach-Parés L, Nonell-Canals A, Bosch-Barrera J, Brunet J, Segura-Carretero A, Sanchez-Martinez M, Encinar JA, Menendez JA. The extra virgin olive oil phenolic oleacein is a dual substrate-inhibitor of catechol-O-methyltransferase. Food Chem Toxicol 2019; 128:35-45. [PMID: 30935952 DOI: 10.1016/j.fct.2019.03.049] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 03/25/2019] [Accepted: 03/26/2019] [Indexed: 12/13/2022]
Abstract
Catechol-containing polyphenols present in coffee and tea, while serving as excellent substrates for catechol-O-methyltransferase (COMT)-catalyzed O-methylation, can also operate as COMT inhibitors. However, little is known about the relationship between COMT and the characteristic phenolics present in extra virgin olive oil (EVOO). We here selected the EVOO dihydroxy-phenol oleacein for a computational study of COMT-driven methylation using classic molecular docking/molecular dynamics simulations and hybrid quantum mechanical/molecular mechanics, which were supported by in vitro activity studies using human COMT. Oleacein could be superimposed onto the catechol-binding site of COMT, maintaining the interactions with the atomic positions involved in methyl transfer from the S-adenosyl-L-methionine cofactor. The transition state structure for the meta-methylation in the O5 position of the oleacein benzenediol moiety was predicted to occur preferentially. Enzyme analysis of the conversion ratio of catechol to O-alkylated guaiacol confirmed the inhibitory effect of oleacein on human COMT, which remained unaltered when tested against the protein version encoded by the functional Val158Met polymorphism of the COMT gene. Our study provides a theoretical determination of how EVOO dihydroxy-phenols can be metabolized via COMT. The ability of oleacein to inhibit COMT adds a new dimension to the physiological and therapeutic utility of EVOO secoiridoids.
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Affiliation(s)
- Elisabet Cuyàs
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism & Cancer Group, Catalan Institute of Oncology, Girona, Spain; Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Sara Verdura
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism & Cancer Group, Catalan Institute of Oncology, Girona, Spain; Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Jesús Lozano-Sánchez
- Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain; Research and Development Functional Food Centre (CIDAF), PTS Granada, Granada, Spain
| | | | | | | | - Joaquim Bosch-Barrera
- Girona Biomedical Research Institute (IDIBGI), Girona, Spain; Medical Oncology, Catalan Institute of Oncology (ICO) Dr. Josep Trueta University Hospital, Girona, Spain; Department of Medical Sciences, Medical School University of Girona, Girona, Spain
| | - Joan Brunet
- Medical Oncology, Catalan Institute of Oncology (ICO) Dr. Josep Trueta University Hospital, Girona, Spain; Department of Medical Sciences, Medical School University of Girona, Girona, Spain; Hereditary Cancer Programme, Catalan Institute of Oncology (ICO), Bellvitge Institute for Biomedical Research (IDIBELL) L'Hospitalet del Llobregat, Barcelona, Spain; Hereditary Cancer Programme, Catalan Institute of Oncology (ICO) Girona Biomedical Research Institute (IDIBGI), Girona, Spain
| | - Antonio Segura-Carretero
- Department of Analytical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain; Research and Development Functional Food Centre (CIDAF), PTS Granada, Granada, Spain
| | | | - José Antonio Encinar
- Institute of Research, Development and Innovation in Biotechnology of Elche (IDiBE) and Molecular and Cell Biology Institute (IBMC), Miguel Hernández University (UMH), Elche, Spain.
| | - Javier A Menendez
- ProCURE (Program Against Cancer Therapeutic Resistance), Metabolism & Cancer Group, Catalan Institute of Oncology, Girona, Spain; Girona Biomedical Research Institute (IDIBGI), Girona, Spain.
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Negative Impact of Carbapenem Methylation on the Reactivity of β-Lactams for Cysteine Acylation as Revealed by Quantum Calculations and Kinetic Analyses. Antimicrob Agents Chemother 2019; 63:AAC.02039-18. [PMID: 30718252 DOI: 10.1128/aac.02039-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 01/29/2019] [Indexed: 11/20/2022] Open
Abstract
The Enterococcus faecium l,d-transpeptidase (Ldtfm) mediates resistance to most β-lactam antibiotics in this bacterium by replacing classical peptidoglycan polymerases. The catalytic Cys of Ldtfm is rapidly acylated by β-lactams belonging to the carbapenem class but not by penams or cephems. We previously reported quantum calculations and kinetic analyses for Ldtfm and showed that the inactivation profile is not determined by differences in drug binding (KD [equilibrium dissociation constant] values in the 50 to 80 mM range). In this study, we analyzed the reaction of a Cys sulfhydryl with various β-lactams in the absence of the enzyme environment in order to compare the intrinsic reactivity of drugs belonging to the penam, cephem, and carbapenem classes. For this purpose, we synthesized cyclic Cys-Asn (cCys-Asn) to generate a soluble molecule with a sulfhydryl closely mimicking a cysteine in a polypeptide chain, thereby avoiding free reactive amino and carboxyl groups. Computational studies identified a thermodynamically favored pathway involving a concerted rupture of the β-lactam amide bond and formation of an amine anion. Energy barriers indicated that the drug reactivity was the highest for nonmethylated carbapenems, intermediate for methylated carbapenems and cephems, and the lowest for penams. Electron-withdrawing groups were key reactivity determinants by enabling delocalization of the negative charge of the amine anion. Acylation rates of cCys-Asn determined by spectrophotometry revealed the same order in the reactivity of β-lactams. We concluded that the rate of Ldtfm acylation is largely determined by the β-lactam reactivity with one exception, as the enzyme catalytic pocket fully compensated for the detrimental effect of carbapenem methylation.
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Dos Santos AM, Cianni L, De Vita D, Rosini F, Leitão A, Laughton CA, Lameira J, Montanari CA. Experimental study and computational modelling of cruzain cysteine protease inhibition by dipeptidyl nitriles. Phys Chem Chem Phys 2019; 20:24317-24328. [PMID: 30211406 DOI: 10.1039/c8cp03320j] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chagas disease affects millions of people in Latin America. This disease is caused by the protozoan parasite Trypanossoma cruzi. The cysteine protease cruzain is a key enzyme for the survival and propagation of this parasite lifecycle. Nitrile-based inhibitors are efficient inhibitors of cruzain that bind by forming a covalent bond with this enzyme. Here, three nitrile-based inhibitors dubbed Neq0409, Neq0410 and Neq0570 were synthesized, and the thermodynamic profile of the bimolecular interaction with cruzain was determined using isothermal titration calorimetry (ITC). The result suggests the inhibition process is enthalpy driven, with a detrimental contribution of entropy. In addition, we have used hybrid Quantum Mechanical/Molecular Mechanical (QM/MM) and Molecular Dynamics (MD) simulations to investigate the reaction mechanism of reversible covalent modification of cruzain by Neq0409, Neq0410 and Neq0570. The computed free energy profile shows that the nucleophilic attack of Cys25 on the carbon C1 of inhibitiors and the proton transfer from His162 to N1 of the dipeptidyl nitrile inhibitor take place in a single step. The calculated free energy of the inhibiton reaction is in agreement with covalent experimental binding. Altogether, the results reported here suggests that nitrile-based inhibitors are good candidates for the development of reversible covalent inhibitors of cruzain and other cysteine proteases.
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Affiliation(s)
- Alberto Monteiro Dos Santos
- Laboratório de Planejamento e Desenvolvimento de Fármacos, Universidade Federal do Pará, Cidade Universitária Prof. José da Silveira Netto, Rua Augusto Correa S/N, Belém-PA, Brazil.
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Yagi K, Yamada K, Kobayashi C, Sugita Y. Anharmonic Vibrational Analysis of Biomolecules and Solvated Molecules Using Hybrid QM/MM Computations. J Chem Theory Comput 2019; 15:1924-1938. [PMID: 30730746 PMCID: PMC8864611 DOI: 10.1021/acs.jctc.8b01193] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
![]()
Quantum
mechanics/molecular mechanics (QM/MM) calculations are
applied for anharmonic vibrational analyses of biomolecules and solvated
molecules. The QM/MM method is implemented into a molecular dynamics
(MD) program, GENESIS, by interfacing with external electronic structure
programs. Following the geometry optimization and the harmonic normal-mode
analysis based on a partial Hessian, the anharmonic potential energy
surface (PES) is generated from QM/MM energies and gradients calculated
at grid points. The PES is used for vibrational self-consistent field
(VSCF) and post-VSCF calculations to compute the vibrational spectrum.
The method is first applied to a phosphate ion in solution. With both
the ion and neighboring water molecules taken as a QM region, IR spectra
of representative hydration structures are calculated by the second-order
vibrational quasi-degenerate perturbation theory (VQDPT2) at the level
of B3LYP/cc-pVTZ and TIP3P force field. A weight-average of IR spectra
over the structures reproduces the experimental spectrum with a mean
absolute deviation of 16 cm–1. Then, the method
is applied to an enzyme, P450 nitric oxide reductase (P450nor), with
the NO molecule bound to a ferric (FeIII) heme. Starting
from snapshot structures obtained from MD simulations of P450nor in
solution, QM/MM calculations have been carried out at the level of
B3LYP-D3/def2-SVP(D). The spin state of FeIII(NO) is likely
a closed-shell singlet state based on a ratio of N–O and Fe–NO
stretching frequencies (νN–O and νFe–NO) calculated for closed- and open-shell singlet
states. The calculated νN–O and νFe–NO overestimate the experimental ones by 120 and
75 cm–1, respectively. The electronic structure
and solvation of FeIII(NO) affect the structure around
the heme of P450nor leading to an increase in νN–O and νFe–NO.
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Affiliation(s)
- Kiyoshi Yagi
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kenta Yamada
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Chigusa Kobayashi
- Computational Biophysics Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
| | - Yuji Sugita
- Theoretical Molecular Science Laboratory, RIKEN Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Computational Biophysics Research Team, RIKEN Center for Computational Science, 7-1-26 Minatojima-Minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan
- Laboratory for Biomolecular Function Simulation, RIKEN Center for Biosystems Dynamics Research, 1-6-5 Minatojima-Minamimachi,
Chuo-ku, Kobe, Hyogo 650-0047, Japan
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39
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Moreno-Del Álamo M, Tabone M, Muñoz-Martínez J, Valverde JR, Alonso JC. Toxin ζ Reduces the ATP and Modulates the Uridine Diphosphate-N-acetylglucosamine Pool. Toxins (Basel) 2019; 11:E29. [PMID: 30634431 PMCID: PMC6356619 DOI: 10.3390/toxins11010029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 12/21/2018] [Accepted: 01/04/2019] [Indexed: 11/20/2022] Open
Abstract
Toxin ζ expression triggers a reversible state of dormancy, diminishes the pool of purine nucleotides, promotes (p)ppGpp synthesis, phosphorylates a fraction of the peptidoglycan precursor uridine diphosphate-N-acetylglucosamine (UNAG), leading to unreactive UNAG-P, induces persistence in a reduced subpopulation, and sensitizes cells to different antibiotics. Here, we combined computational analyses with biochemical experiments to examine the mechanism of toxin ζ action. Free ζ toxin showed low affinity for UNAG. Toxin ζ bound to UNAG hydrolyzed ATP·Mg2+, with the accumulation of ADP, Pi, and produced low levels of phosphorylated UNAG (UNAG-P). Toxin ζ, which has a large ATP binding pocket, may temporally favor ATP binding in a position that is distant from UNAG, hindering UNAG phosphorylation upon ATP hydrolysis. The residues D67, E116, R158 and R171, involved in the interaction with metal, ATP, and UNAG, were essential for the toxic and ATPase activities of toxin ζ; whereas the E100 and T128 residues were partially dispensable. The results indicate that ζ bound to UNAG reduces the ATP concentration, which indirectly induces a reversible dormant state, and modulates the pool of UNAG.
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Affiliation(s)
- María Moreno-Del Álamo
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str., 28049 Madrid, Spain.
| | - Mariangela Tabone
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str., 28049 Madrid, Spain.
| | - Juan Muñoz-Martínez
- Scientific Computing Service, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str., 28049 Madrid, Spain.
| | - José R Valverde
- Scientific Computing Service, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str., 28049 Madrid, Spain.
| | - Juan C Alonso
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, CNB-CSIC, 3 Darwin Str., 28049 Madrid, Spain.
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40
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Lederer J, Kaiser W, Mattoni A, Gagliardi A. Machine Learning–Based Charge Transport Computation for Pentacene. ADVANCED THEORY AND SIMULATIONS 2018. [DOI: 10.1002/adts.201800136] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jonas Lederer
- Department of Electrical and Computer EngineeringTechnical University of MunichKarlstraße 45 80333 Munich Germany
| | - Waldemar Kaiser
- Department of Electrical and Computer EngineeringTechnical University of MunichKarlstraße 45 80333 Munich Germany
| | - Alessandro Mattoni
- Istituto Officina dei MaterialiCNR‐IOM SLACS CagliariCittadella Universitaria09042‐I Monserrato Italy
| | - Alessio Gagliardi
- Department of Electrical and Computer EngineeringTechnical University of MunichKarlstraße 45 80333 Munich Germany
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41
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Pedregal JR, Funes‐Ardoiz I, Sciortino G, Sánchez‐Aparicio J, Ujaque G, Lledós A, Maréchal J, Maseras F. GARLEEK: Adding an extra flavor to ONIOM. J Comput Chem 2018; 40:381-386. [DOI: 10.1002/jcc.25612] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 08/28/2018] [Accepted: 09/05/2018] [Indexed: 01/17/2023]
Affiliation(s)
- Jaime Rodríguez‐Guerra Pedregal
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Bellaterra Catalonia Spain
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology Avgda. Països Catalans, 16, 43007, Tarragona Catalonia Spain
| | - Ignacio Funes‐Ardoiz
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology Avgda. Països Catalans, 16, 43007, Tarragona Catalonia Spain
| | - Giuseppe Sciortino
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Bellaterra Catalonia Spain
| | | | - Gregori Ujaque
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Bellaterra Catalonia Spain
| | - Agustí Lledós
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Bellaterra Catalonia Spain
| | - Jean‐Didie Maréchal
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Bellaterra Catalonia Spain
| | - Feliu Maseras
- Departament de QuímicaUniversitat Autònoma de Barcelona 08193 Bellaterra Catalonia Spain
- Institute of Chemical Research of Catalonia (ICIQ), The Barcelona Institute of Science and Technology Avgda. Països Catalans, 16, 43007, Tarragona Catalonia Spain
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42
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Keinan S, Hatcher Frush E, Shipman WJ. Leveraging Cloud Computing for In-Silico Drug Design Using the Quantum Molecular Design (QMD) Framework. Comput Sci Eng 2018. [DOI: 10.1109/mcse.2018.042781327] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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43
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Schmitt E, Bourgeois G, Gondry M, Aleksandrov A. Cyclization Reaction Catalyzed by Cyclodipeptide Synthases Relies on a Conserved Tyrosine Residue. Sci Rep 2018; 8:7031. [PMID: 29728603 PMCID: PMC5935735 DOI: 10.1038/s41598-018-25479-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/20/2018] [Indexed: 11/23/2022] Open
Abstract
Cyclodipeptide synthases (CDPSs) form various cyclodipeptides from two aminoacyl tRNAs via a stepwise mechanism with the formation of a dipeptidyl enzyme intermediate. As a final step of the catalytic reaction, the dipeptidyl group undergoes intramolecular cyclization to generate the target cyclodipeptide product. In this work, we investigated the cyclization reaction in the cyclodipeptide synthase AlbC using QM/MM methods and free energy simulations. The results indicate that the catalytic Y202 residue is in its neutral protonated form, and thus, is not likely to serve as a general base during the reaction. We further demonstrate that the reaction relies on the conserved residue Y202 serving as a proton relay, and the direct proton transfer from the amino group to S37 of AlbC is unlikely. Calculations reveal that the hydroxyl group of tyrosine is more suitable for the proton transfer than hydroxyl groups of other amino acids, such as serine and threonine. Results also show that the residues E182, N40, Y178 and H203 maintain the correct conformation of the dipeptide needed for the cyclization reaction. The mechanism discovered in this work relies on the amino groups conserved among the entire CDPS family and, thus is expected to be universal among CDPSs.
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Affiliation(s)
- Emmanuelle Schmitt
- Laboratoire de Biochimie (CNRS UMR7654), Department of Biology, Ecole Polytechnique, F-91128, Palaiseau, France
| | - Gabrielle Bourgeois
- Laboratoire de Biochimie (CNRS UMR7654), Department of Biology, Ecole Polytechnique, F-91128, Palaiseau, France
| | - Muriel Gondry
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198, Gif-sur-Yvette cedex, France
| | - Alexey Aleksandrov
- Laboratoire de Biochimie (CNRS UMR7654), Department of Biology, Ecole Polytechnique, F-91128, Palaiseau, France.
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44
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Culka M, Huwiler SG, Boll M, Ullmann GM. Breaking Benzene Aromaticity-Computational Insights into the Mechanism of the Tungsten-Containing Benzoyl-CoA Reductase. J Am Chem Soc 2017; 139:14488-14500. [PMID: 28918628 DOI: 10.1021/jacs.7b07012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic compounds are environmental pollutants with toxic and carcinogenic properties. Despite the stability of aromatic rings, bacteria are able to degrade the aromatic compounds into simple metabolites and use them as growth substrates under oxic or even under anoxic conditions. In anaerobic microorganisms, most monocyclic aromatic growth substrates are converted to the central intermediate benzoyl-coenzyme A, which is enzymatically reduced to cyclohexa-1,5-dienoyl-CoA. The strictly anaerobic bacterium Geobacter metallireducens uses the class II benzoyl-CoA reductase complex for this reaction. The catalytic BamB subunit of this complex harbors an active site tungsten-bis-pyranopterin cofactor with the metal being coordinated by five protein/cofactor-derived sulfur atoms and a sixth, so far unknown, ligand. Although BamB has been biochemically and structurally characterized, its mechanism still remains elusive. Here we use continuum electrostatic and QM/MM calculations to model benzoyl-CoA reduction by BamB. We aim to elucidate the identity of the sixth ligand of the active-site tungsten ion together with the interplay of the electron and proton transfer events during the aromatic ring reduction. On the basis of our calculations, we propose that benzoyl-CoA reduction is initiated by a hydrogen atom transfer from a W(IV) species with an aqua ligand, yielding W(V)-[OH-] and a substrate radical intermediate. In the next step, a proton-assisted second electron transfer takes place with a conserved active-site histidine serving as the second proton donor. Interestingly, our calculations suggest that the electron for the second reduction step is taken from the pyranopterin cofactors rather than from the tungsten ion. The resulting cationic radical, which is distributed over both pyranopterins, is stabilized by conserved anionic amino acid residues. The stepwise mechanism of the reduction shows similarities to the Birch reduction known from organic chemistry. However, the strict coupling of protons and electrons allows the reaction to proceed under milder conditions.
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Affiliation(s)
- Martin Culka
- Computational Biochemistry, University of Bayreuth , Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
| | - Simona G Huwiler
- Microbiology, Faculty of Biology, University of Freiburg , Schänzlestrasse 1, 79104 Freiburg, Germany
| | - Matthias Boll
- Microbiology, Faculty of Biology, University of Freiburg , Schänzlestrasse 1, 79104 Freiburg, Germany
| | - G Matthias Ullmann
- Computational Biochemistry, University of Bayreuth , Universitätsstrasse 30, NW I, 95447 Bayreuth, Germany
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45
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Dos Santos AM, Lima AH, Alves CN, Lameira J. Unraveling the Addition-Elimination Mechanism of EPSP Synthase through Computer Modeling. J Phys Chem B 2017; 121:8626-8637. [PMID: 28829128 DOI: 10.1021/acs.jpcb.7b05063] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Enolpyruvyl transfer from phosphoenolpyruvate (PEP) to the hydroxyl group of shikimate-5-OH-3-phosphate (S3P) is catalyzed by 5-enolpyruvylshikimate 3-phosphate (EPSP) synthase in a reaction that involves breaking the C-O bond of PEP. Catalysis involves an addition-elimination mechanism with the formation of a tetrahedral intermediate (THI). Experiments have elucidated the mechanism of THI formation and breakdown. However, the catalytic action of EPSP synthase and the individual roles of catalytic residues Asp313 and Glu341 remains unclear. We have used a hybrid quantum mechanical/molecular mechanical (QM/MM) approach to explore the free energy surface in a reaction catalyzed by EPSP synthase. The Glu341 was the most favorable acid/base catalyst. Our results indicate that the protonation of PEP C3 precedes the nucleophilic attack on PEP C2 in the addition mechanism. Also, the breaking of the C-O bond of THI to form an EPSP cation intermediate must occur before proton transfer from PEP C3 to Glu341 in the elimination mechanism. Analysis of the FES supports cationic intermediate formation during the reaction catalyzed by EPSP synthase. Finally, the computational model indicates a proton transfer shift (Hammond shift) from Glu341 to C3 for an enzyme-based reaction with the shifted transition state, earlier than in the reference reaction in water.
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Affiliation(s)
- Alberto M Dos Santos
- Institute of Biological Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
| | - Anderson H Lima
- Institute of Biological Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
| | - Cláudio Nahum Alves
- Institute of Exact and Natural Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
| | - Jerônimo Lameira
- Institute of Biological Sciences, Federal University of Pará , Belém, PA 66075-110, Brazil
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46
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Frush EH, Sekharan S, Keinan S. In Silico Prediction of Ligand Binding Energies in Multiple Therapeutic Targets and Diverse Ligand Sets—A Case Study on BACE1, TYK2, HSP90, and PERK Proteins. J Phys Chem B 2017; 121:8142-8148. [DOI: 10.1021/acs.jpcb.7b07224] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Elizabeth Hatcher Frush
- Cloud Pharmaceuticals, Inc., 6 Davis Drive,
Research Triangle Park, North Carolina 27709, United States
| | - Sivakumar Sekharan
- Cloud Pharmaceuticals, Inc., 6 Davis Drive,
Research Triangle Park, North Carolina 27709, United States
| | - Shahar Keinan
- Cloud Pharmaceuticals, Inc., 6 Davis Drive,
Research Triangle Park, North Carolina 27709, United States
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47
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Mechanisms and Specificity of Phenazine Biosynthesis Protein PhzF. Sci Rep 2017; 7:6272. [PMID: 28740244 PMCID: PMC5524880 DOI: 10.1038/s41598-017-06278-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 06/12/2017] [Indexed: 11/08/2022] Open
Abstract
Phenazines are bacterial virulence and survival factors with important roles in infectious disease. PhzF catalyzes a key reaction in their biosynthesis by isomerizing (2 S,3 S)-2,3-dihydro-3-hydroxy anthranilate (DHHA) in two steps, a [1,5]-hydrogen shift followed by tautomerization to an aminoketone. While the [1,5]-hydrogen shift requires the conserved glutamate E45, suggesting acid/base catalysis, it also shows hallmarks of a sigmatropic rearrangement, namely the suprafacial migration of a non-acidic proton. To discriminate these mechanistic alternatives, we employed enzyme kinetic measurements and computational methods. Quantum mechanics/molecular mechanics (QM/MM) calculations revealed that the activation barrier of a proton shuttle mechanism involving E45 is significantly lower than that of a sigmatropic [1,5]-hydrogen shift. QM/MM also predicted a large kinetic isotope effect, which was indeed observed with deuterated substrate. For the tautomerization, QM/MM calculations suggested involvement of E45 and an active site water molecule, explaining the observed stereochemistry. Because these findings imply that PhzF can act only on a limited substrate spectrum, we also investigated the turnover of DHHA derivatives, of which only O-methyl and O-ethyl DHHA were converted. Together, these data reveal how PhzF orchestrates a water-free with a water-dependent step. Its unique mechanism, specificity and essential role in phenazine biosynthesis may offer opportunities for inhibitor development.
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48
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Shaik MM, Bhattacharjee N, Feliks M, Ng KKS, Field MJ. Norovirus RNA-dependent RNA polymerase: A computational study of metal-binding preferences. Proteins 2017; 85:1435-1445. [PMID: 28383118 DOI: 10.1002/prot.25304] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 12/21/2022]
Abstract
Norovirus (NV) RNA-dependent RNA polymerase (RdRP) is essential for replicating the genome of the virus, which makes this enzyme a key target for the development of antiviral agents against NV gastroenteritis. In this work, a complex of NV RdRP bound to manganese ions and an RNA primer-template duplex was investigated using X-ray crystallography and hybrid quantum chemical/molecular mechanical simulations. Experimentally, the complex crystallized in a tetragonal crystal form. The nature of the primer/template duplex binding in the resulting structure indicates that the complex is a closed back-tracked state of the enzyme, in which the 3'-end of the primer occupies the position expected for the post-incorporated nucleotide before translocation. Computationally, it is found that the complex can accept a range of divalent metal cations without marked distortions in the active site structure. The highest binding energy is for copper, followed closely by manganese and iron, and then by zinc, nickel, and cobalt. Proteins 2017; 85:1435-1445. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Md Munan Shaik
- Division of Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, 02115.,Department of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, Massachusetts, 02115
| | - Nicholus Bhattacharjee
- Dynamo Team/DYNAMOP Group, UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, Grenoble Cedex 9, 38044, France
| | - Mikolaj Feliks
- Dynamo Team/DYNAMOP Group, UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, Grenoble Cedex 9, 38044, France
| | - Kenneth K-S Ng
- Department of Biological Sciences and Alberta Glycomics Centre, University of Calgary, Calgary, Alberta, Canada
| | - Martin J Field
- Dynamo Team/DYNAMOP Group, UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, Grenoble Cedex 9, 38044, France
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49
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Affiliation(s)
- Martin J. Field
- Dynamo Team/DYNAMOP Group,
UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France
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50
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Bhattacharjee N, Feliks M, Shaik MM, Field MJ. Catalytic Mechanism of Peptidoglycan Deacetylase: A Computational Study. J Phys Chem B 2016; 121:89-99. [DOI: 10.1021/acs.jpcb.6b10625] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Nicholus Bhattacharjee
- Dynamo
Team/DYNAMOP Group, UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France
| | - Mikolaj Feliks
- Dynamo
Team/DYNAMOP Group, UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France
| | - Md Munan Shaik
- Division
of Molecular Medicine, Boston Children’s Hospital, Boston, Massachusetts 02115, United States
- Department
of Pediatrics, Harvard Medical School, 3 Blackfan Street, Boston, Massachusetts 02115, United States
| | - Martin J. Field
- Dynamo
Team/DYNAMOP Group, UMR5075, Université Grenoble I, CEA, CNRS, Institut de Biologie Structurale, 71 Avenue des Martyrs, CS 10090, 38044 Grenoble Cedex 9, France
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