1
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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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2
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Sever M, Merzel F. Collective Domain Motion Facilitates Water Transport in SGLT1. Int J Mol Sci 2023; 24:10528. [PMID: 37445706 DOI: 10.3390/ijms241310528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/17/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
The human sodium-glucose cotransporter protein (SGLT1) is an important representative of the sodium solute symporters belonging to the secondary active transporters that are critical to the homeostasis of sugar, sodium, and water in the cell. The underlying transport mechanism of SGLT1 is based on switching between inward- and outward-facing conformations, known as the alternating access model, which is crucial for substrate transport, and has also been postulated for water permeation. However, the nature of water transport remains unclear and is disputed along the passive and active transport, with the latter postulating the presence of the pumping effect. To better examine the water transport in SGLT1, we performed a series of equilibrium all-atom molecular dynamics simulations, totaling over 6 μs of sample representative conformational states of SGLT1 and its complexes, with the natural substrates, ions, and inhibitors. In addition to elucidating the basic physical factors influencing water permeation, such as channel openings and energetics, we focus on dynamic flexibility and its relationship with domain motion. Our results clearly demonstrate a dependence of instantaneous water flux on the channel opening and local water diffusion in the channel, strongly supporting the existence of a passive water transport in SGLT1. In addition, a strong correlation found between the local water diffusion and protein domain motion, resembling the "rocking-bundle" motion, reveals its facilitating role in the water transport.
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Affiliation(s)
- Marko Sever
- Theory Departnemt, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Franci Merzel
- Theory Departnemt, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
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3
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Varvdekar B, Prabhakant A, Krishnan M. Response of Terahertz Protein Vibrations to Ligand Binding: Calmodulin-Peptide Complexes as a Case Study. J Chem Inf Model 2022; 62:1669-1679. [PMID: 35312312 DOI: 10.1021/acs.jcim.1c01344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Terahertz vibrations are sensitive reporters of the structure and interactions of proteins. Ligand binding alters the nature and distribution of these collective vibrations. The ligand-induced changes in the terahertz protein vibrations contribute to the binding entropy and to the overall thermodynamic stability of the resultant protein-ligand complexes. Here, we have examined the response of the low-frequency (below 6 terahertz) collective vibrations of the calcium-loaded calmodulin (CaM) to binding to five different ligands, both in the presence and absence of water, using normal-mode analysis and molecular dynamics simulations. A comparison of the vibrational spectra of hydrated and dry systems reveals that protein-solvent interactions stiffen the terahertz protein vibrations and that these solvent-coupled collective vibrations contribute significantly to the hydration-sensitive variation in the vibrational entropy of CaM. In the absence of water, the low-frequency vibrations of CaM are stiffened by ligand binding. On the contrary, the number and the cumulative vibrational entropy of low-frequency vibrational modes (ω < 200 cm-1) of the hydrated CaM are increased noticeably after binding to the peptides, indicating binding-induced softening of collective vibrations of the protein. Although the calculated and experimental binding affinities of the chosen complexes correlated reasonably well, no systematic correlation was observed between the protein vibrational entropy and the binding affinity. The results underscored the importance of the interplay of protein-ligand and solvent interactions in modulating the low-frequency vibrations of proteins.
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Affiliation(s)
- Bhagyesh Varvdekar
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad 500032, India
| | - Akshay Prabhakant
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad 500032, India
| | - Marimuthu Krishnan
- Center for Computational Natural Sciences and Bioinformatics (CCNSB), International Institute of Information Technology, Gachibowli, Hyderabad 500032, India
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4
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Kneller DW, Gerlits O, Daemen LL, Pavlova A, Gumbart JC, Cheng Y, Kovalevsky A. Joint neutron/molecular dynamics vibrational spectroscopy reveals softening of HIV-1 protease upon binding of a tight inhibitor. Phys Chem Chem Phys 2022; 24:3586-3597. [PMID: 35089990 PMCID: PMC8940534 DOI: 10.1039/d1cp05487b] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Biomacromolecules are inherently dynamic, and their dynamics are interwoven into function. The fast collective vibrational dynamics in proteins occurs in the low picosecond timescale corresponding to frequencies of ∼5-50 cm-1. This sub-to-low THz frequency regime covers the low-amplitude collective breathing motions of a whole protein and vibrations of the constituent secondary structure elements, such as α-helices, β-sheets and loops. We have used inelastic neutron scattering experiments in combination with molecular dynamics simulations to demonstrate the vibrational dynamics softening of HIV-1 protease, a target of HIV/AIDS antivirals, upon binding of a tight clinical inhibitor darunavir. Changes in the vibrational density of states of matching structural elements in the two monomers of the homodimeric protein are not identical, indicating asymmetric effects of darunavir on the vibrational dynamics. Three of the 11 major secondary structure elements contribute over 40% to the overall changes in the vibrational density of states upon darunavir binding. Molecular dynamics simulations informed by experiments allowed us to estimate that the altered vibrational dynamics of the protease would contribute -3.6 kcal mol-1 at 300 K, or 25%, to the free energy of darunavir binding. As HIV-1 protease drug resistance remains a concern, our results open a new avenue to help establish a direct quantitative link between protein vibrational dynamics and drug resistance.
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Affiliation(s)
- Daniel W. Kneller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A
| | - Oksana Gerlits
- Department of Natural Sciences, Tennessee Wesleyan University, Athens, TN 37303, U.S.A
| | - Luke L. Daemen
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, U.S.A
| | - Anna Pavlova
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - James C. Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, U.S.A
| | - Yongqiang Cheng
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
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5
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Papež P, Praprotnik M. Dissipative Particle Dynamics Simulation of Ultrasound Propagation through Liquid Water. J Chem Theory Comput 2022; 18:1227-1240. [PMID: 35001631 PMCID: PMC8830050 DOI: 10.1021/acs.jctc.1c01020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Ultrasound is widely
used as a noninvasive method in therapeutic
and diagnostic applications. These can be further optimized by computational
approaches, as they allow for controlled testing and rational optimization
of the ultrasound parameters, such as frequency and amplitude. Usually,
continuum numerical methods are used to simulate ultrasound propagating
through different tissue types. In contrast, ultrasound simulations
using particle description are less common, as the implementation
is challenging. In this work, a dissipative particle dynamics model
is used to perform ultrasound simulations in liquid water. The effects
of frequency and thermostat parameters are studied and discussed.
We show that frequency and thermostat parameters affect not only the
attenuation but also the computed speed of sound. The present study
paves the way for development and optimization of a virtual ultrasound
machine for large-scale biomolecular simulations.
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Affiliation(s)
- Petra Papež
- Laboratory for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1001, Slovenia.,Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, Ljubljana, SI-1000, Slovenia
| | - Matej Praprotnik
- Laboratory for Molecular Modeling, National Institute of Chemistry, Hajdrihova 19, Ljubljana, SI-1001, Slovenia.,Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, Ljubljana, SI-1000, Slovenia
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6
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Kneller DW, Li H, Galanie S, Phillips G, Labbé A, Weiss KL, Zhang Q, Arnould MA, Clyde A, Ma H, Ramanathan A, Jonsson CB, Head MS, Coates L, Louis JM, Bonnesen PV, Kovalevsky A. Structural, Electronic, and Electrostatic Determinants for Inhibitor Binding to Subsites S1 and S2 in SARS-CoV-2 Main Protease. J Med Chem 2021; 64:17366-17383. [PMID: 34705466 PMCID: PMC8565456 DOI: 10.1021/acs.jmedchem.1c01475] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Indexed: 02/08/2023]
Abstract
Creating small-molecule antivirals specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins is crucial to battle coronavirus disease 2019 (COVID-19). SARS-CoV-2 main protease (Mpro) is an established drug target for the design of protease inhibitors. We performed a structure-activity relationship (SAR) study of noncovalent compounds that bind in the enzyme's substrate-binding subsites S1 and S2, revealing structural, electronic, and electrostatic determinants of these sites. The study was guided by the X-ray/neutron structure of Mpro complexed with Mcule-5948770040 (compound 1), in which protonation states were directly visualized. Virtual reality-assisted structure analysis and small-molecule building were employed to generate analogues of 1. In vitro enzyme inhibition assays and room-temperature X-ray structures demonstrated the effect of chemical modifications on Mpro inhibition, showing that (1) maintaining correct geometry of an inhibitor's P1 group is essential to preserve the hydrogen bond with the protonated His163; (2) a positively charged linker is preferred; and (3) subsite S2 prefers nonbulky modestly electronegative groups.
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Affiliation(s)
- Daniel W. Kneller
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
| | - Hui Li
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Stephanie Galanie
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Gwyndalyn Phillips
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
| | - Audrey Labbé
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Kevin L. Weiss
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
| | - Qiu Zhang
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
| | - Mark A. Arnould
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Austin Clyde
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439, USA
- Department of Computer Science, University of Chicago, Chicago, IL 60615, USA
| | - Heng Ma
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Arvind Ramanathan
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Data Science and Learning Division, Argonne National Laboratory, Lemont, IL 60439, USA
- Consortium for Advanced Science and Engineering, University of Chicago, Chicago, IL 60615
| | - Colleen B. Jonsson
- Department of Microbiology, Immunology and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Martha S. Head
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Joint Institute for Biological Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Leighton Coates
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Second Target Station, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - John M. Louis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, DHHS, Bethesda, MD 20892-0520, USA
| | - Peter V. Bonnesen
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, USA
- National Virtual Biotechnology Laboratory, US Department of Energy, Washington, DC, 20585, USA
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7
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Romo TD, Grossfield A, Markelz AG. Persistent Protein Motions in a Rugged Energy Landscape Revealed by Normal Mode Ensemble Analysis. J Chem Inf Model 2020; 60:6419-6426. [PMID: 33103888 DOI: 10.1021/acs.jcim.0c00879] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Proteins are allosteric machines that couple motions at distinct, often distant, sites to control biological function. Low-frequency structural vibrations are a mechanism of this long-distance connection and are often used computationally to predict correlations, but experimentally identifying the vibrations associated with specific motions has proved challenging. Spectroscopy is an ideal tool to explore these excitations, but measurements have been largely unable to identify important frequency bands. The result is at odds with some previous calculations and raises the question what methods could successfully characterize protein structural vibrations. Here we show the lack of spectral structure arises in part from the variations in protein structure as the protein samples the energy landscape. However, by averaging over the energy landscape as sampled using an aggregate 18.5 μs of all-atom molecular dynamics simulation of hen egg white lysozyme and normal-mode analyses, we find vibrations with large overlap with functional displacements are surprisingly concentrated in narrow frequency bands. These bands are not apparent in either the ensemble averaged vibrational density of states or isotropic absorption. However, in the case of the ensemble averaged anisotropic absorption, there is persistent spectral structure and overlap between this structure and the functional displacement frequency bands. We systematically lay out heuristics for calculating the spectra robustly, including the need for statistical sampling of the protein and inclusion of adequate water in the spectral calculation. The results show the congested spectrum of these complex molecules obscures important frequency bands associated with function and reveal a method to overcome this congestion by combining structurally sensitive spectroscopy with robust normal mode ensemble analysis.
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Affiliation(s)
- Tod D Romo
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, United States
| | - Alan Grossfield
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York 14642, United States
| | - Andrea G Markelz
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, United States
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8
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Dajnowicz S, Cheng Y, Daemen LL, Weiss KL, Gerlits O, Mueser TC, Kovalevsky A. Substrate Binding Stiffens Aspartate Aminotransferase by Altering the Enzyme Picosecond Vibrational Dynamics. ACS OMEGA 2020; 5:18787-18797. [PMID: 32775880 PMCID: PMC7408236 DOI: 10.1021/acsomega.0c01900] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/14/2020] [Indexed: 06/11/2023]
Abstract
Protein dynamics on various time scales from femtoseconds to milliseconds impacts biological function by driving proteins to conformations conducive to ligand binding and creating functional states in enzyme catalysis. Neutron vibrational spectroscopy carried out by measuring inelastic neutron scattering from protein molecules in combination with molecular simulations has the unique ability of detecting and visualizing changes in the picosecond protein vibrational dynamics due to ligand binding. Here we present neutron vibrational spectra of a homodimeric pyridoxal 5'-phosphate-dependent enzyme, aspartate aminotransferase, obtained from the open internal aldimine and closed external aldimine conformational states. We observe that in the external aldimine state the protein structure stiffens relative to the internal aldimine state, indicating rigidified vibrational dynamics on the picosecond time scale in the low-frequency regime of 5-50 cm-1. Our molecular dynamics simulations indicate substantial changes in the picosecond dynamics of the enzyme secondary structure elements upon substrate binding, with the largest contributions from just two helices and the β-sheet.
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Affiliation(s)
- Steven Dajnowicz
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
- Department
of Chemistry and Biochemistry, University
of Toledo, Toledo, Ohio 43606, United States
| | - Yongqiang Cheng
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Luke L. Daemen
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Kevin L. Weiss
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
| | - Oksana Gerlits
- Department
of Natural Sciences, Tennessee Wesleyan
University, Athens, Tennessee 37303, United States
| | - Timothy C. Mueser
- Department
of Chemistry and Biochemistry, University
of Toledo, Toledo, Ohio 43606, United States
| | - Andrey Kovalevsky
- Neutron
Scattering Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830, United States
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9
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Sarter M, Niether D, Koenig BW, Lohstroh W, Zamponi M, Jalarvo NH, Wiegand S, Fitter J, Stadler AM. Strong Adverse Contribution of Conformational Dynamics to Streptavidin-Biotin Binding. J Phys Chem B 2019; 124:324-335. [PMID: 31710813 DOI: 10.1021/acs.jpcb.9b08467] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular dynamics plays an important role for the biological function of proteins. For protein ligand interactions, changes of conformational entropy of protein and hydration layer are relevant for the binding process. Quasielastic neutron scattering (QENS) was used to investigate differences in protein dynamics and conformational entropy of ligand-bound and ligand-free streptavidin. Protein dynamics were probed both on the fast picosecond time scale using neutron time-of-flight spectroscopy and on the slower nanosecond time scale using high-resolution neutron backscattering spectroscopy. We found the internal equilibrium motions of streptavidin and the corresponding mean square displacements (MSDs) to be greatly reduced upon biotin binding. On the basis of the observed MSDs, we calculated the difference of conformational entropy ΔSconf of the protein component between ligand-bound and ligand-free streptavidin. The rather large negative ΔSconf value (-2 kJ mol-1 K-1 on the nanosecond time scale) obtained for the streptavidin tetramer seems to be counterintuitive, given the exceptionally high affinity of streptavidin-biotin binding. Literature data on the total entropy change ΔS observed upon biotin binding to streptavidin, which includes contributions from both the protein and the hydration water, suggest partial compensation of the unfavorable ΔSconf by a large positive entropy gain of the surrounding hydration layer and water molecules that are displaced during ligand binding.
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Affiliation(s)
- Mona Sarter
- I. Physikalisches Institut (IA), AG Biophysik , RWTH Aachen , Sommerfeldstrasse 14 , Aachen D-52074 , Germany
| | | | | | - Wiebke Lohstroh
- Heinz Maier-Leibnitz Zentrum , Technische Universität München , Garching D-85747 , Germany
| | - Michaela Zamponi
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ) , Forschungszentrum Jülich GmbH , Lichtenbergstrasse 1 , Garching D-85748 , Germany
| | - Niina H Jalarvo
- Neutron Scattering Division , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831-6475 , United States
| | - Simone Wiegand
- Department für Chemie - Physikalische Chemie , Universität zu Köln , Cologne D-50939 , Germany
| | - Jörg Fitter
- I. Physikalisches Institut (IA), AG Biophysik , RWTH Aachen , Sommerfeldstrasse 14 , Aachen D-52074 , Germany.,Institute of Complex Systems, Molecular Biophysics (ICS-5) , Forschungszentrum Jülich GmbH , Jülich D-52428 , Germany
| | - Andreas M Stadler
- Institute of Physical Chemistry , RWTH Aachen University , Landoltweg 2 , Aachen D-52056 , Germany
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10
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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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11
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Kežar A, Kavčič L, Polák M, Nováček J, Gutiérrez-Aguirre I, Žnidarič MT, Coll A, Stare K, Gruden K, Ravnikar M, Pahovnik D, Žagar E, Merzel F, Anderluh G, Podobnik M. Structural basis for the multitasking nature of the potato virus Y coat protein. SCIENCE ADVANCES 2019; 5:eaaw3808. [PMID: 31328164 PMCID: PMC6636993 DOI: 10.1126/sciadv.aaw3808] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 06/10/2019] [Indexed: 05/02/2023]
Abstract
Potato virus Y (PVY) is among the most economically important plant pathogens. Using cryoelectron microscopy, we determined the near-atomic structure of PVY's flexuous virions, revealing a previously unknown lumenal interplay between extended carboxyl-terminal regions of the coat protein units and viral RNA. RNA-coat protein interactions are crucial for the helical configuration and stability of the virion, as revealed by the unique near-atomic structure of RNA-free virus-like particles. The structures offer the first evidence for plasticity of the coat protein's amino- and carboxyl-terminal regions. Together with mutational analysis and in planta experiments, we show their crucial role in PVY infectivity and explain the ability of the coat protein to perform multiple biological tasks. Moreover, the high modularity of PVY virus-like particles suggests their potential as a new molecular scaffold for nanobiotechnological applications.
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Affiliation(s)
- Andreja Kežar
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- Graduate School of Biomedicine, Medical Faculty, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Luka Kavčič
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Martin Polák
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - Jiří Nováček
- Central European Institute of Technology, Masaryk University, Kamenice 753/5, Brno 625 00, Czech Republic
| | - Ion Gutiérrez-Aguirre
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Magda Tušek Žnidarič
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Anna Coll
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Katja Stare
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Kristina Gruden
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
| | - Maja Ravnikar
- Department of Biotechnology and Systems Biology, National Institute of Biology, Večna pot 111, 1000 Ljubljana, Slovenia
- University of Nova Gorica, Vipavska cesta, 5000 Nova Gorica, Slovenia
| | - David Pahovnik
- Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Ema Žagar
- Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Franci Merzel
- Theory Department, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Marjetka Podobnik
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
- Corresponding author.
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12
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Saouessi M, Peters J, Kneller GR. Asymptotic analysis of quasielastic neutron scattering data from human acetylcholinesterase reveals subtle dynamical changes upon ligand binding. J Chem Phys 2019; 150:161104. [PMID: 31042885 DOI: 10.1063/1.5094625] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this paper, we show that subtle changes in the internal dynamics of human acetylcholinesterase upon ligand binding can be extracted from quasielastic neutron scattering data by employing a nonexponential relaxation model for the intermediate scattering function. The relaxation is here described by a stretched Mittag-Leffler function, which exhibits slow power law decay for long times. Our analysis reveals that binding of a Huperzine A ligand increases the atomic motional amplitudes of the enzyme and slightly slows down its internal diffusive motions. This result is interpreted within an energy landscape picture for the motion of the hydrogen atoms.
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Affiliation(s)
- Melek Saouessi
- Centre de Biophysique 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 Biophysique Moléculaire, CNRS and Université d'Orléans, Rue Charles Sadron, 45071 Orléans, France
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13
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Kaynak BT, Doruker P. Protein-Ligand Complexes as Constrained Dynamical Systems. J Chem Inf Model 2019; 59:2352-2358. [PMID: 30912658 DOI: 10.1021/acs.jcim.8b00946] [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
This study focuses on how the low-frequency end of the vibrational spectrum related to the functional motions changes as a protein binds to a small ligand(s). Our recently proposed residue-specific (RESPEC) elastic network model provides a natural laboratory for this aim due to its systematic mixed coarse-graining approach and parametrization. Current analysis on a large data set of protein-ligand complexes reveals a universal curve enclosing the frequency distributions, which bears the features of previous computational and experimental studies. We mostly observe positive frequency shifts in the collective modes of the protein upon ligand binding. This observation, conforming to the Rayleigh-Courant-Fisher theorem, points to a constraining effect imposed by ligands on protein dynamics, which may be accompanied by a negative vibrational entropy difference. Positive frequency shifts in the global modes can thus be linked to the harmonic well getting steeper, because of interactions with the ligand(s).
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Affiliation(s)
- Burak T Kaynak
- Department of Computational and Systems Biology, School of Medicine , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States
| | - Pemra Doruker
- Department of Computational and Systems Biology, School of Medicine , University of Pittsburgh , Pittsburgh , Pennsylvania 15261 , United States.,Department of Chemical Engineering and Polymer Research Center , Bogazici University , 34342 Bebek , Istanbul , Turkey
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14
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Abstract
A methodology to cluster proteins based on their dynamics’ similarity is presented. For each pair of proteins from a dataset, the structures are superimposed, and the Anisotropic Network Model modes of motions are calculated. The twelve slowest modes from each protein are matched using a local mode alignment algorithm based on the local sequence alignment algorithm of Smith–Waterman. The dynamical similarity distance matrix is calculated based on the top scoring matches of each pair and the proteins are clustered using a hierarchical clustering algorithm. The utility of this method is exemplified on a dataset of protein chains from the globin family and a dataset of tetrameric hemoglobins. The results demonstrate the effect of the quaternary structure of globin members on their intrinsic dynamics and show good ability to distinguish between different states of hemoglobin, revealing the dynamical relations between them.
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Affiliation(s)
- Dror Tobi
- Department of Molecular Biology, Ariel University, Ariel, Israel
- Department of Computer Sciences, Ariel University, Ariel, Israel
- * E-mail:
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15
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Aharoni R, Tobi D. Dynamical comparison between myoglobin and hemoglobin. Proteins 2018; 86:1176-1183. [PMID: 30183107 DOI: 10.1002/prot.25598] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/22/2018] [Accepted: 08/31/2018] [Indexed: 01/29/2023]
Abstract
Myoglobin and hemoglobin are globular hemeproteins, when the former is a monomer and the latter a heterotetramer. Despite the structural similarity of myoglobin to α and β subunits of hemoglobin, there is a functional difference between the two proteins, owing to the quaternary structure of hemoglobin. The effect of the quaternary structure of hemoglobin on the intrinsic dynamics of its subunits is explored by dynamical comparison of the two proteins. Anisotropic Network Model modes of motion were calculated for hemoglobin and myoglobin. Dynamical comparison between the proteins was performed using global and local Anisotropic Network Model mode alignment algorithms based on the algorithms of Smith-Waterman and Needleman-Wunsch for sequence comparison. The results indicate that the quaternary structure of hemoglobin substantially alters the intrinsic dynamics of its subunits, an effect that may contribute to the functional difference between the two proteins. Local dynamics similarity between the proteins is still observed at the major exit route of the ligand.
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Affiliation(s)
- Rotem Aharoni
- Department of Molecular Biology, Ariel University, Ariel, Israel
| | - Dror Tobi
- Department of Molecular Biology, Ariel University, Ariel, Israel.,Department of Computer Sciences, Ariel University, Ariel, Israel
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16
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Goethe M, Fita I, Rubi JM. Testing the mutual information expansion of entropy with multivariate Gaussian distributions. J Chem Phys 2018; 147:224102. [PMID: 29246041 DOI: 10.1063/1.4996847] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The mutual information expansion (MIE) represents an approximation of the configurational entropy in terms of low-dimensional integrals. It is frequently employed to compute entropies from simulation data of large systems, such as macromolecules, for which brute-force evaluation of the full configurational integral is intractable. Here, we test the validity of MIE for systems consisting of more than m = 100 degrees of freedom (dofs). The dofs are distributed according to multivariate Gaussian distributions which were generated from protein structures using a variant of the anisotropic network model. For the Gaussian distributions, we have semi-analytical access to the configurational entropy as well as to all contributions of MIE. This allows us to accurately assess the validity of MIE for different situations. We find that MIE diverges for systems containing long-range correlations which means that the error of consecutive MIE approximations grows with the truncation order n for all tractable n ≪ m. This fact implies severe limitations on the applicability of MIE, which are discussed in the article. For systems with correlations that decay exponentially with distance, MIE represents an asymptotic expansion of entropy, where the first successive MIE approximations approach the exact entropy, while MIE also diverges for larger orders. In this case, MIE serves as a useful entropy expansion when truncated up to a specific truncation order which depends on the correlation length of the system.
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Affiliation(s)
- Martin Goethe
- Department of Condensed Matter Physics, University of Barcelona, Carrer Martí i Franqués 1, 08028 Barcelona, Spain
| | - Ignacio Fita
- Molecular Biology Institute of Barcelona (IBMB-CSIC, Maria de Maeztu Unit of Excellence), Carrer Baldiri Reixac 4-8, 08028 Barcelona, Spain
| | - J Miguel Rubi
- Department of Condensed Matter Physics, University of Barcelona, Carrer Martí i Franqués 1, 08028 Barcelona, Spain
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17
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Abstract
Dynamic neutron scattering directly probes motions in biological systems on femtosecond to microsecond timescales. When combined with molecular dynamics simulation and normal mode analysis, detailed descriptions of the forms and frequencies of motions can be derived. We examine vibrations in proteins, the temperature dependence of protein motions, and concepts describing the rich variety of motions detectable using neutrons in biological systems at physiological temperatures. New techniques for deriving information on collective motions using coherent scattering are also reviewed.
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Affiliation(s)
- Jeremy C Smith
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6309, USA; .,Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Pan Tan
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Loukas Petridis
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6309, USA; .,Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Liang Hong
- School of Physics and Astronomy and Institute of Natural Sciences, Shanghai Jiao Tong University, Shanghai 200240, China
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18
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Tobi D. Dynamical differences of hemoglobin and the ionotropic glutamate receptor in different states revealed by a new dynamics alignment method. Proteins 2017; 85:1507-1517. [PMID: 28459140 DOI: 10.1002/prot.25311] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 04/02/2017] [Accepted: 04/24/2017] [Indexed: 12/26/2022]
Abstract
A new algorithm for comparison of protein dynamics is presented. Compared protein structures are superposed and their modes of motions are calculated using the anisotropic network model. The obtained modes are aligned using the dynamic programming algorithm of Needleman and Wunsch, commonly used for sequence alignment. Dynamical comparison of hemoglobin in the T and R2 states reveals that the dynamics of the allosteric effector 2,3-bisphosphoglycerate binding site is different in the two states. These differences can contribute to the selectivity of the effector to the T state. Similar comparison of the ionotropic glutamate receptor in the kainate+(R,R)-2b and ZK bound states reveals that the kainate+(R,R)-2b bound states slow modes describe upward motions of ligand binding domain and the transmembrane domain regions. Such motions may lead to the opening of the receptor. The upper lobes of the LBDs of the ZK bound state have a smaller interface with the amino terminal domains above them and have a better ability to move together. The present study exemplifies the use of dynamics comparison as a tool to study protein function. Proteins 2017; 85:1507-1517. © 2014 Wiley Periodicals, Inc.
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Affiliation(s)
- Dror Tobi
- Department of Computer Sciences, Ariel University, Ariel, 40700, Israel.,Department of Molecular Biology, Ariel University, Ariel, 40700, Israel
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19
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Goethe M, Fita I, Rubi JM. Vibrational entropy of a protein: large differences between distinct conformations. J Chem Theory Comput 2016; 11:351-9. [PMID: 26574230 DOI: 10.1021/ct500696p] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this article, it is investigated whether vibrational entropy (VE) is an important contribution to the free energy of globular proteins at ambient conditions. VE represents the major configurational-entropy contribution of these proteins. By definition, it is an average of the configurational entropies of the protein within single minima of the energy landscape, weighted by their occupation probabilities. Its large part originates from thermal motion of flexible torsion angles giving rise to the finite peak widths observed in torsion angle distributions. While VE may affect the equilibrium properties of proteins, it is usually neglected in numerical calculations as its consideration is difficult. Moreover, it is sometimes believed that all well-packed conformations of a globular protein have similar VE anyway. Here, we measure explicitly the VE for six different conformations from simulation data of a test protein. Estimates are obtained using the quasi-harmonic approximation for three coordinate sets, Cartesian, bond-angle-torsion (BAT), and a new set termed rotamer-degeneracy lifted BAT coordinates by us. The new set gives improved estimates as it overcomes a known shortcoming of the quasi-harmonic approximation caused by multiply populated rotamer states, and it may serve for VE estimation of macromolecules in a very general context. The obtained VE values depend considerably on the type of coordinates used. However, for all coordinate sets we find large entropy differences between the conformations, of the order of the overall stability of the protein. This result may have important implications on the choice of free energy expressions used in software for protein structure prediction, protein design, and NMR refinement.
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Affiliation(s)
- Martin Goethe
- Departament de Física Fonamental, Universitat de Barcelona , Martı́ i Franquès 1, 08028 Barcelona, Spain
| | - Ignacio Fita
- Institut de Biologia Molecular de Barcelona , (CSIC), Baldiri Reixac 10, 08028 Barcelona, Spain
| | - J Miguel Rubi
- Departament de Física Fonamental, Universitat de Barcelona , Martı́ i Franquès 1, 08028 Barcelona, Spain
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20
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Garbuzynskiy SO, Finkelstein AV. Calculation of mobility and entropy of the binding of molecules by crystals. Mol Biol 2016. [DOI: 10.1134/s0026893316020060] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Niessen KA, Xu M, Markelz AG. Terahertz optical measurements of correlated motions with possible allosteric function. Biophys Rev 2015; 7:201-216. [PMID: 28510171 DOI: 10.1007/s12551-015-0168-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/26/2015] [Indexed: 10/23/2022] Open
Abstract
A suggested mechanism for allosteric response is the distortion of the energy landscape with agonist binding changing the protein structure's access to functional configurations. Intramolecular vibrations are indicative of the energy landscape and may have trajectories that enable functional conformational change. Here, we discuss the development of an optical method to measure the intramolecular vibrations in proteins, namely, crystal anisotropy terahertz microscopy, and the various approaches which can be used to identify the spectral data with specific structural motions.
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Affiliation(s)
- Katherine A Niessen
- Department of Physics, University at Buffalo (SUNY), Buffalo, NY, 14260, USA
| | - Mengyang Xu
- Department of Physics, University at Buffalo (SUNY), Buffalo, NY, 14260, USA
| | - A G Markelz
- Department of Physics, University at Buffalo (SUNY), Buffalo, NY, 14260, USA.
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22
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Ellingson SR, Miao Y, Baudry J, Smith JC. Multi-conformer ensemble docking to difficult protein targets. J Phys Chem B 2014; 119:1026-34. [PMID: 25198248 DOI: 10.1021/jp506511p] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Large-scale ensemble docking is investigated using five proteins from the Directory of Useful Decoys (DUD, dud.docking.org ) for which docking to crystal structures has proven difficult. Molecular dynamics trajectories are produced for each protein and an ensemble of representative conformational structures extracted from the trajectories. Docking calculations are performed on these selected simulation structures and ensemble-based enrichment factors compared with those obtained using docking in crystal structures of the same protein targets or random selection of compounds. Simulation-derived snapshots are found with improved enrichment factors that increase the chemical diversity of docking hits for four of the five selected proteins. A combination of all the docking results obtained from molecular dynamics simulation followed by selection of top-ranking compounds appears to be an effective strategy for increasing the number and diversity of hits when using docking to screen large libraries of chemicals against difficult protein targets.
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Affiliation(s)
- Sally R Ellingson
- Genome Science and Technology, University of Tennessee , Knoxville, Tennessee, United States
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23
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Hong L, Petridis L, Smith JC. Biomolecular Structure and Dynamics with Neutrons: The View from Simulation. Isr J Chem 2014. [DOI: 10.1002/ijch.201300137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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24
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Sowole MA, Konermann L. Effects of Protein–Ligand Interactions on Hydrogen/Deuterium Exchange Kinetics: Canonical and Noncanonical Scenarios. Anal Chem 2014; 86:6715-22. [DOI: 10.1021/ac501849n] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Modupeola A. Sowole
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department
of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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25
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Janda JO, Popal A, Bauer J, Busch M, Klocke M, Spitzer W, Keller J, Merkl R. H2rs: deducing evolutionary and functionally important residue positions by means of an entropy and similarity based analysis of multiple sequence alignments. BMC Bioinformatics 2014; 15:118. [PMID: 24766829 PMCID: PMC4021312 DOI: 10.1186/1471-2105-15-118] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Accepted: 04/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The identification of functionally important residue positions is an important task of computational biology. Methods of correlation analysis allow for the identification of pairs of residue positions, whose occupancy is mutually dependent due to constraints imposed by protein structure or function. A common measure assessing these dependencies is the mutual information, which is based on Shannon's information theory that utilizes probabilities only. Consequently, such approaches do not consider the similarity of residue pairs, which may degrade the algorithm's performance. One typical algorithm is H2r, which characterizes each individual residue position k by the conn(k)-value, which is the number of significantly correlated pairs it belongs to. RESULTS To improve specificity of H2r, we developed a revised algorithm, named H2rs, which is based on the von Neumann entropy (vNE). To compute the corresponding mutual information, a matrix A is required, which assesses the similarity of residue pairs. We determined A by deducing substitution frequencies from contacting residue pairs observed in the homologs of 35 809 proteins, whose structure is known. In analogy to H2r, the enhanced algorithm computes a normalized conn(k)-value. Within the framework of H2rs, only statistically significant vNE values were considered. To decide on significance, the algorithm calculates a p-value by performing a randomization test for each individual pair of residue positions. The analysis of a large in silico testbed demonstrated that specificity and precision were higher for H2rs than for H2r and two other methods of correlation analysis. The gain in prediction quality is further confirmed by a detailed assessment of five well-studied enzymes. The outcome of H2rs and of a method that predicts contacting residue positions (PSICOV) overlapped only marginally. H2rs can be downloaded from http://www-bioinf.uni-regensburg.de. CONCLUSIONS Considering substitution frequencies for residue pairs by means of the von Neumann entropy and a p-value improved the success rate in identifying important residue positions. The integration of proven statistical concepts and normalization allows for an easier comparison of results obtained with different proteins. Comparing the outcome of the local method H2rs and of the global method PSICOV indicates that such methods supplement each other and have different scopes of application.
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Affiliation(s)
| | | | | | | | | | | | | | - Rainer Merkl
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, D-93040 Regensburg, Germany.
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26
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Konermann L, Rodriguez AD, Sowole MA. Type 1 and Type 2 scenarios in hydrogen exchange mass spectrometry studies on protein–ligand complexes. Analyst 2014; 139:6078-87. [DOI: 10.1039/c4an01307g] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Ligand binding to a protein can elicit a wide range of responses when studied by HDX mass spectrometry.
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Affiliation(s)
- Lars Konermann
- Department of Chemistry
- The University of Western Ontario
- London, Canada
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27
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Tobi D. Large-scale analysis of the dynamics of enzymes. Proteins 2013; 81:1910-8. [PMID: 23737241 DOI: 10.1002/prot.24335] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/21/2013] [Accepted: 05/24/2013] [Indexed: 12/26/2022]
Abstract
Protein enzymes enable the cell to execute chemical reactions in short time by accelerating the rate of the reactions in a selective manner. The motions or dynamics of the enzymes are essential for their function. Comparison of the dynamics of a set of 1247 nonhomologous enzymes was performed. For each enzyme, the slowest modes of motion are calculated using the Gaussian network model (GNM) and they are globally aligned. Alignment is done using the dynamic programming algorithm of Needleman and Wunsch, commonly used for sequence alignment. Only 96 pairs of proteins were identified to have three similar GNM slow modes with 63 of them having a similar structure. The most frequent slowest mode of motion describes a two domains anticorrelated motion that characterizes at least 23% of the enzymes. Therefore, dynamics uniqueness cannot be accounted for by the slowest mode itself but rather by the combination of several slow modes. Different quaternary structure packing can restrain the motion of enzyme subunits differently and may serve as another mechanism that increases the dynamics uniqueness.
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Affiliation(s)
- Dror Tobi
- Department of Computer Sciences and Mathematics, Ariel University, Ariel, 40700, Israel; Department of Molecular Biology, Ariel University, Ariel, 40700, Israel
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28
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Lerbret A, Affouard F, Hédoux A, Krenzlin S, Siepmann J, Bellissent-Funel MC, Descamps M. How strongly does trehalose interact with lysozyme in the solid state? Insights from molecular dynamics simulation and inelastic neutron scattering. J Phys Chem B 2012; 116:11103-16. [PMID: 22894179 DOI: 10.1021/jp3058096] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Therapeutic proteins are usually conserved in glassy matrixes composed of stabilizing excipients and a small amount of water, which both control their long-term stability, and thus their potential use in medical treatments. To shed some light on the protein-matrix interactions in such systems, we performed molecular dynamics (MD) simulations on matrixes of (i) the model globular protein lysozyme (L), (ii) the well-known bioprotectant trehalose (T), and (iii) the 1:1 (in weight) lysozyme/trehalose mixture (LT), at hydration levels h of 0.0, 0.075, and 0.15 (in g of water/g of protein or sugar). We also supplemented these simulations with complementary inelastic neutron scattering (INS) experiments on the L, T, and LT lyophilized (freeze-dried) samples. The densities and free volume distributions indicate that trehalose improves the molecular packing of the LT glass with respect to the L one. Accordingly, the low-frequency vibrational densities of states (VDOS) and the mean square displacements (MSDs) of lysozyme reveal that it is less flexible-and thus less likely to unfold-in the presence of trehalose. Furthermore, at low contents (h = 0.075), water systematically stiffens the vibrational motions of lysozyme and trehalose, whereas it increases their MSDs on the nanosecond (ns) time scale. This stems from the hydrogen bonds (HBs) that lysozyme and trehalose form with water, which, interestingly, are stronger than the ones they form with each other but which, nonetheless, relax faster on the ns time scale, given the larger mobility of water. Moreover, lysozyme interacts preferentially with water in the hydrated LT mixtures, and trehalose appears to slow down significantly the relaxation of lysozyme-water HBs. Overall, our results suggest that the stabilizing efficiency of trehalose arises from its ability to (i) increase the number of HBs formed by proteins in the dry state and (ii) make the HBs formed by water with proteins stable on long (>ns) time scales.
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Affiliation(s)
- Adrien Lerbret
- Unité Matériaux Et Transformations, UMR CNRS 8207, Université Lille Nord de France, USTL, 59655 Villeneuve d'Ascq, France.
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29
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Paciaroni A, Orecchini A, Haertlein M, Moulin M, Conti Nibali V, De Francesco A, Petrillo C, Sacchetti F. Vibrational Collective Dynamics of Dry Proteins in the Terahertz Region. J Phys Chem B 2012; 116:3861-5. [DOI: 10.1021/jp211190q] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alessandro Paciaroni
- Dipartimento di Fisica, Università degli Studi di Perugia, Via Pascoli, I-06123 Perugia, Italy
- Istituto Officina dei Materiali, Unità di Perugia, c/o Dipartimento di Fisica, Università di Perugia, I-06123 Perugia, Italy
| | - Andrea Orecchini
- Dipartimento di Fisica, Università degli Studi di Perugia, Via Pascoli, I-06123 Perugia, Italy
- Istituto Officina dei Materiali, Unità di Perugia, c/o Dipartimento di Fisica, Università di Perugia, I-06123 Perugia, Italy
- Institut Laue Langevin, 6 rue J. Horowitz, F-38042 Grenoble, France
| | | | - Martine Moulin
- Institut Laue Langevin, 6 rue J. Horowitz, F-38042 Grenoble, France
| | - Valeria Conti Nibali
- Dipartimento di Fisica, Università degli Studi di Messina, via Salita Sperone, I-98166 Messina, Italy
| | - Alessio De Francesco
- CNR, Istituto Officina dei Materiali, Unità di Grenoble, Institut Laue Langevin, 6 rue J. Horowitz, F-38042 Grenoble, France
| | - Caterina Petrillo
- Dipartimento di Fisica, Università degli Studi di Perugia, Via Pascoli, I-06123 Perugia, Italy
- Istituto Officina dei Materiali, Unità di Perugia, c/o Dipartimento di Fisica, Università di Perugia, I-06123 Perugia, Italy
| | - Francesco Sacchetti
- Dipartimento di Fisica, Università degli Studi di Perugia, Via Pascoli, I-06123 Perugia, Italy
- Istituto Officina dei Materiali, Unità di Perugia, c/o Dipartimento di Fisica, Università di Perugia, I-06123 Perugia, Italy
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30
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Functional domain motions in proteins on the ~1-100 ns timescale: comparison of neutron spin-echo spectroscopy of phosphoglycerate kinase with molecular-dynamics simulation. Biophys J 2012; 102:1108-17. [PMID: 22404933 DOI: 10.1016/j.bpj.2012.01.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 12/09/2011] [Accepted: 01/03/2012] [Indexed: 11/22/2022] Open
Abstract
Protein function often requires large-scale domain motion. An exciting new development in the experimental characterization of domain motions in proteins is the application of neutron spin-echo spectroscopy (NSE). NSE directly probes coherent (i.e., pair correlated) scattering on the ~1-100 ns timescale. Here, we report on all-atom molecular-dynamics (MD) simulation of a protein, phosphoglycerate kinase, from which we calculate small-angle neutron scattering (SANS) and NSE scattering properties. The simulation-derived and experimental-solution SANS results are in excellent agreement. The contributions of translational and rotational whole-molecule diffusion to the simulation-derived NSE and potential problems in their estimation are examined. Principal component analysis identifies types of domain motion that dominate the internal motion's contribution to the NSE signal, with the largest being classic hinge bending. The associated free-energy profiles are quasiharmonic and the frictional properties correspond to highly overdamped motion. The amplitudes of the motions derived by MD are smaller than those derived from the experimental analysis, and possible reasons for this difference are discussed. The MD results confirm that a significant component of the NSE arises from internal dynamics. They also demonstrate that the combination of NSE with MD is potentially useful for determining the forms, potentials of mean force, and time dependence of functional domain motions in proteins.
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31
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Tobi D. Dynamics alignment: Comparison of protein dynamics in the scop database. Proteins 2012; 80:1167-76. [DOI: 10.1002/prot.24017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 11/27/2011] [Accepted: 12/13/2011] [Indexed: 11/07/2022]
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Clark RD, Waldman M. Lions and tigers and bears, oh my! Three barriers to progress in computer-aided molecular design. J Comput Aided Mol Des 2011; 26:29-34. [PMID: 22160503 PMCID: PMC3268986 DOI: 10.1007/s10822-011-9504-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 11/29/2011] [Indexed: 11/28/2022]
Abstract
The computational chemistry and cheminformatics community faces many challenges to advancing the state of the art. We discuss three of those challenges here: accurately estimating the contribution of entropy to ligand binding; reliably estimating the uncertainties in model predictions for new molecules; and being able to effectively curate the ever-expanding literature and commercial databases needed to build new models.
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