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Hassani AN, Haris L, Appel M, Seydel T, Stadler AM, Kneller GR. Signature of functional enzyme dynamics in quasielastic neutron scattering spectra: The case of phosphoglycerate kinase. J Chem Phys 2023; 159:141102. [PMID: 37818999 DOI: 10.1063/5.0166124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023] Open
Abstract
We present an analysis of high-resolution quasi-elastic neutron scattering spectra of phosphoglycerate kinase which elucidates the influence of the enzymatic activity on the dynamics of the protein. We show that in the active state the inter-domain motions are amplified and the intra-domain asymptotic power-law relaxation ∝t-α is accelerated, with a reduced coefficient α. Employing an energy landscape picture of protein dynamics, this observation can be translated into a widening of the distribution of energy barriers separating conformational substates of the protein.
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Affiliation(s)
- Abir N Hassani
- Centre de Biophysique Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Luman Haris
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Markus Appel
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Tilo Seydel
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Andreas M Stadler
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
| | - Gerald R Kneller
- Centre de Biophysique Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
- Laboratoire des biomolécules, Département de chimie, Ecole Normale Supérieure, 75005 Paris, France
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Gerlits O, Fajer M, Cheng X, Blumenthal DK, Radić Z, Kovalevsky A. Structural and dynamic effects of paraoxon binding to human acetylcholinesterase by X-ray crystallography and inelastic neutron scattering. Structure 2022; 30:1538-1549.e3. [PMID: 36265484 PMCID: PMC9637784 DOI: 10.1016/j.str.2022.09.006] [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: 07/26/2022] [Revised: 09/07/2022] [Accepted: 09/25/2022] [Indexed: 11/06/2022]
Abstract
Organophosphorus (OP) compounds, including nerve agents and some pesticides, covalently bind to the catalytic serine of human acetylcholinesterase (hAChE), thereby inhibiting acetylcholine hydrolysis necessary for efficient neurotransmission. Oxime antidotes can reactivate the OP-conjugated hAChE, but reactivation efficiency can be low for pesticides, such as paraoxon (POX). Understanding structural and dynamic determinants of OP inhibition and reactivation can provide insights to design improved reactivators. Here, X-ray structures of hAChE with unaged POX, with POX and oximes MMB4 and RS170B, and with MMB4 are reported. A significant conformational distortion of the acyl loop was observed upon POX binding, being partially restored to the native conformation by oximes. Neutron vibrational spectroscopy combined with molecular dynamics simulations showed that picosecond vibrational dynamics of the acyl loop soften in the ∼20-50 cm-1 frequency range. The acyl loop structural perturbations may be correlated with its picosecond vibrational dynamics to yield more comprehensive template for structure-based reactivator design.
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Affiliation(s)
- Oksana Gerlits
- Department of Natural Sciences, Tennessee Wesleyan University, Athens, TN 37303, USA
| | - Mikolai Fajer
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Xiaolin Cheng
- Division of Medicinal Chemistry & Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA
| | - Donald K Blumenthal
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, UT 84112, USA
| | - Zoran Radić
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093-0657, USA.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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Hassani AN, Haris L, Appel M, Seydel T, Stadler AM, Kneller GR. Multiscale relaxation dynamics and diffusion of myelin basic protein in solution studied by quasielastic neutron scattering. J Chem Phys 2022; 156:025102. [PMID: 35032992 DOI: 10.1063/5.0077100] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We report an analysis of high-resolution quasielastic neutron scattering spectra from Myelin Basic Protein (MBP) in solution, comparing the spectra at three different temperatures (283, 303, and 323 K) for a pure D2O buffer and a mixture of D2O buffer with 30% of deuterated trifluoroethanol (TFE). Accompanying experiments with dynamic light scattering and Circular Dichroism (CD) spectroscopy have been performed to obtain, respectively, the global diffusion constant and the secondary structure content of the molecule for both buffers as a function of temperature. Modeling the decay of the neutron intermediate scattering function by the Mittag-Leffler relaxation function, ϕ(t) = Eα(-(t/τ)α) (0 < α < 1), we find that trifluoroethanol slows down the relaxation dynamics of the protein at 283 K and leads to a broader relaxation rate spectrum. This effect vanishes with increasing temperature, and at 323 K, its relaxation dynamics is identical in both solvents. These results are coherent with the data from dynamic light scattering, which show that the hydrodynamic radius of MBP in TFE-enriched solutions does not depend on temperature and is only slightly smaller compared to the pure D2O buffer, except for 283 K, where it is much reduced. In accordance with these observations, the CD spectra reveal that TFE induces essentially a partial transition from β-strands to α-helices, but only a weak increase in the total secondary structure content, leaving about 50% of the protein unfolded. The results show that MBP is for all temperatures and in both buffers an intrinsically disordered protein and that TFE essentially induces a reduction in its hydrodynamic radius and its relaxation dynamics at low temperatures.
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Affiliation(s)
- Abir N Hassani
- Centre de Biophysique Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
| | - Luman Haris
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Markus Appel
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Tilo Seydel
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Andreas M Stadler
- Jülich Centre for Neutron Science (JCNS-1) and Institute of Biological Information Processing (IBI-8), Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Gerald R Kneller
- Centre de Biophysique Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
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Petersen MH, Telling MTF, Kneller G, Bordallo HN. Revisiting the modeling of quasielastic neutron scattering from bulk water. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227201012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Quasi-elastic neutron scattering (QENS) from bulk-water at 300 K, measured on the IRIS backscattering neutron spectrometer (ISIS, UK), is interpreted using the jump diffusion model (JDM), a “minimalistic” multi-timescale relaxation model (MRM) and molecular dynamics simulations (MD). In the case of MRM data analysis is performed in the time domain, where the relaxation of the intermediate scattering function is described by a stretched Mittag-Leffler function, Eα(−(|t|/τ)α). This function displays an asymptotic power law decay and contains the exponential relaxation function as a special case (α = 1). To further compare the two approaches, MD simulations of bulk water were performed using the SPCE force field and the resulting MD trajectories analysed using the nMoldyn software. We show that both JDM and MRM accurately describe the diffusion of bulk water observed by QENS at all length scales, and confirm that MD simulations do not fully describe the quantum effects of jump diffusion.
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Zeller D, Tan P, Hong L, Di Bari D, Garcia Sakai V, Peters J. Differences between calcium rich and depleted alpha-lactalbumin investigated by molecular dynamics simulations and incoherent neutron scattering. Phys Rev E 2020; 101:032415. [PMID: 32289905 DOI: 10.1103/physreve.101.032415] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 02/21/2020] [Indexed: 11/07/2022]
Abstract
We present a study comparing atomic motional amplitudes in calcium rich and depleted alpha-lactalbumin. The investigations were performed by elastic incoherent neutron scattering (EINS) and molecular dynamics (MD) simulations. As the variations were expected to be very small, three different hydration levels and timescales (instrumental resolutions) were measured. In addition, we used two models to extract the mean square displacements (MSDs) from the EINS data, one taking into account the motional heterogeneity of the MSD. At a timescale of several nanoseconds, small differences in the amplitudes between the calcium enriched and depleted alpha-lactalbumin are visible, whereas at lower timescales no changes can be concluded within the statistics. The results are compared to MD simulations at 280 and 300 K by extracting the MSDs of the trajectories in two separate ways: first by direct calculation, and second by a virtual neutron experiment using the same models as for the experimental data. We show that the simulated data give qualitatively similar results as the experimental data but quantitatively there are differences. Furthermore, the distribution of the MSDs in the simulations suggests that the inclusion of heterogeneity is reasonable for alpha-lactalbumin, but a bi-or trimodal approach may be sufficient.
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Affiliation(s)
- Dominik Zeller
- University Grenoble Alpes, LiPhy, CNRS, F-38000 Grenoble, France and Institut Laue Langevin, F-38042 Grenoble Cedex 9, France
| | - Pan Tan
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liang Hong
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Daniele Di Bari
- University Grenoble Alpes, LiPhy, CNRS, F-38000 Grenoble, France and Institut Laue Langevin, F-38042 Grenoble Cedex 9, France.,Physics Department, University of Perugia, 06123 Perugia, Italy
| | - Victoria Garcia Sakai
- ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX, United Kingdom
| | - Judith Peters
- University Grenoble Alpes, LiPhy, CNRS, F-38000 Grenoble, France and Institut Laue Langevin, F-38042 Grenoble Cedex 9, France
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Saouessi M, Peters J, Kneller GR. Frequency domain modeling of quasielastic neutron scattering from hydrated protein powders: Application to free and inhibited human acetylcholinesterase. J Chem Phys 2019; 151:125103. [PMID: 31575200 DOI: 10.1063/1.5121703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
This article reports on a frequency domain analysis of quasielastic neutron scattering spectra from free and Huperzine-A-inhibited human acetylcholinesterase, extending a recent time domain analysis of the same experimental data [M. Saouessi et al., J. Chem. Phys. 150, 161104 (2019)]. An important technical point here is the construction of a semianalytical model for the resolution-broadened dynamic structure factor that can be fitted to the experimental spectra. We find comparable parameters as in our previous study and demonstrate that our model is sensitive to subpercent changes in the experimental data, which are caused by reversible binding of the inhibitor Huperzine A.
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Affiliation(s)
- Melek Saouessi
- Centre de Biophys. Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
| | - Judith Peters
- Institut Laue Langevin, 71 Avenue des Martyrs, 38042 Grenoble Cedex 9, France
| | - Gerald R Kneller
- Centre de Biophys. Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
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