1
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Leighton RE, Frontiera RR. Quantifying Bacteriorhodopsin Activity as a Function of its Local Environment with a Raman-Based Assay. J Phys Chem B 2023; 127:8833-8841. [PMID: 37812499 DOI: 10.1021/acs.jpcb.3c04802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/11/2023]
Abstract
Bacteriorhodopsin (bR) is a transmembrane protein that functions as a light-driven proton pump in halophilic archaea. The bR photocycle has been well-characterized; however, these measurements almost exclusively measured purified bR, outside of its native membrane. To investigate what effect the cellular environment has on the bR photocycle, we have developed a Raman-based assay that can monitor the activity of the bR in a variety of conditions, including in its native membrane. The assay uses two continuous-wave lasers, one to initiate photochemistry and one to monitor bR activity. The excitation leads to the steady-state depletion of ground-state bR, which directly relates to the population of photocycle intermediate states. We have used this assay to monitor bR activity both in vitro and in vivo. Our in vitro measurements confirm that our assay is sensitive to bulk environmental changes reported in the literature. Our in vivo measurements show a decrease in bR activity with increasing extracellular pH for bR in its native membrane. The difference in activity with increasing pH indicates that the native membrane environment affects the function of bR. This assay opens the door to future measurements into understanding how the local environment of this transmembrane protein affects function.
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Affiliation(s)
- Ryan E Leighton
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Renee R Frontiera
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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2
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Chen SH, Weiss KL, Stanley C, Bhowmik D. Structural characterization of an intrinsically disordered protein complex using integrated small-angle neutron scattering and computing. Protein Sci 2023; 32:e4772. [PMID: 37646172 PMCID: PMC10503416 DOI: 10.1002/pro.4772] [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: 04/28/2023] [Revised: 08/22/2023] [Accepted: 08/27/2023] [Indexed: 09/01/2023]
Abstract
Characterizing structural ensembles of intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) of proteins is essential for studying structure-function relationships. Due to the different neutron scattering lengths of hydrogen and deuterium, selective labeling and contrast matching in small-angle neutron scattering (SANS) becomes an effective tool to study dynamic structures of disordered systems. However, experimental timescales typically capture measurements averaged over multiple conformations, leaving complex SANS data for disentanglement. We hereby demonstrate an integrated method to elucidate the structural ensemble of a complex formed by two IDRs. We use data from both full contrast and contrast matching with residue-specific deuterium labeling SANS experiments, microsecond all-atom molecular dynamics (MD) simulations with four molecular mechanics force fields, and an autoencoder-based deep learning (DL) algorithm. From our combined approach, we show that selective deuteration provides additional information that helps characterize structural ensembles. We find that among the four force fields, a99SB-disp and CHARMM36m show the strongest agreement with SANS and NMR experiments. In addition, our DL algorithm not only complements conventional structural analysis methods but also successfully differentiates NMR and MD structures which are indistinguishable on the free energy surface. Lastly, we present an ensemble that describes experimental SANS and NMR data better than MD ensembles generated by one single force field and reveal three clusters of distinct conformations. Our results demonstrate a new integrated approach for characterizing structural ensembles of IDPs.
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Affiliation(s)
- Serena H. Chen
- Computational Sciences and Engineering DivisionOak Ridge National LaboratoryOak RidgeTennesseeUSA
| | - Kevin L. Weiss
- Neutron Scattering DivisionOak Ridge National LaboratoryOak RidgeTennesseeUSA
| | - Christopher Stanley
- Computational Sciences and Engineering DivisionOak Ridge National LaboratoryOak RidgeTennesseeUSA
| | - Debsindhu Bhowmik
- Computational Sciences and Engineering DivisionOak Ridge National LaboratoryOak RidgeTennesseeUSA
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3
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Rhinehardt K, Dong M. Computational analysis of protein conformational heterogeneity. J Biomol Struct Dyn 2022; 40:12100-12105. [PMID: 34424141 DOI: 10.1080/07391102.2021.1967784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this paper, we applied the molecular dynamics (MD) simulations and used thermolysin as the system to study the overall protein dynamics and side chain dihedral angles across the Arrhenius break. Simulations were performed at a high temperature of 36 °C which is above the previously observed Arrhenius break, and the lower temperature of 20 °C which is below the Arrhenius break. We observed different protein dynamics and conformational heterogeneity of side chain dihedral angles of thermolysin at the two temperatures. Our results indicated that certain regions of thermolysin have a higher level of fluctuation at lower temperature. A temperature dependent dihedral angles were also observed at the two temperatures. The changes observed in the protein indicated key areas of temperature sensitivity within the protein.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kristen Rhinehardt
- Department of Computational Data Science and Engineering, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
| | - Ming Dong
- Department of Chemistry, North Carolina Agricultural and Technical State University, Greensboro, NC, USA
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4
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Rosi BP, D’Angelo A, Buratti E, Zanatta M, Tavagnacco L, Natali F, Zamponi M, Noferini D, Corezzi S, Zaccarelli E, Comez L, Sacchetti F, Paciaroni A, Petrillo C, Orecchini A. Impact of the Environment on the PNIPAM Dynamical Transition Probed by Elastic Neutron Scattering. Macromolecules 2022. [DOI: 10.1021/acs.macromol.2c00177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Benedetta P. Rosi
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
| | - Arianna D’Angelo
- Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, 510 Rue André Rivière, 91405 Orsay, France
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, Cedex 9, France
| | - Elena Buratti
- Dipartimento di Fisica, CNR-ISC c/o Università di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Marco Zanatta
- Dipartimento di Fisica, Università di Trento, via Sommarive 14, 38123 Trento, Italy
| | - Letizia Tavagnacco
- Dipartimento di Fisica, CNR-ISC c/o Università di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Francesca Natali
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, Cedex 9, France
- CNR-IOM, OGG, 71 Avenue des Martyrs, 38043 Grenoble, Cedex 9, France
| | - Michaela Zamponi
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, 85747 Garching, Germany
| | - Daria Noferini
- Jülich Centre for Neutron Science at Heinz Maier-Leibnitz Zentrum, Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, 85747 Garching, Germany
- European Spallation Source ERIC, Box 176, 221 00 Lund, Sweden
| | - Silvia Corezzi
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
| | - Emanuela Zaccarelli
- Dipartimento di Fisica, CNR-ISC c/o Università di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Roma, Italy
| | - Lucia Comez
- Dipartimento di Fisica e Geologia, CNR-IOM c/o Università di Perugia, via Alessandro Pascoli, 06123 Perugia, Italy
| | - Francesco Sacchetti
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
| | - Alessandro Paciaroni
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
| | - Caterina Petrillo
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
| | - Andrea Orecchini
- Dipartimento di Fisica e Geologia, Università di Perugia, Via Alessandro Pascoli, 06123 Perugia, Italy
- Dipartimento di Fisica e Geologia, CNR-IOM c/o Università di Perugia, via Alessandro Pascoli, 06123 Perugia, Italy
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5
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Dynamic Coupling of Tyrosine 185 with the Bacteriorhodopsin Photocycle, as Revealed by Chemical Shifts, Assisted AF-QM/MM Calculations and Molecular Dynamic Simulations. Int J Mol Sci 2021; 22:ijms222413587. [PMID: 34948384 PMCID: PMC8709120 DOI: 10.3390/ijms222413587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 12/14/2021] [Accepted: 12/16/2021] [Indexed: 11/23/2022] Open
Abstract
Aromatic residues are highly conserved in microbial photoreceptors and play crucial roles in the dynamic regulation of receptor functions. However, little is known about the dynamic mechanism of the functional role of those highly conserved aromatic residues during the receptor photocycle. Tyrosine 185 (Y185) is one of the highly conserved aromatic residues within the retinal binding pocket of bacteriorhodopsin (bR). In this study, we explored the molecular mechanism of its dynamic coupling with the bR photocycle by automated fragmentation quantum mechanics/molecular mechanics (AF-QM/MM) calculations and molecular dynamic (MD) simulations based on chemical shifts obtained by 2D solid-state NMR correlation experiments. We observed that Y185 plays a significant role in regulating the retinal cis–trans thermal equilibrium, stabilizing the pentagonal H-bond network, participating in the orientation switch of Schiff Base (SB) nitrogen, and opening the F42 gate by interacting with the retinal and several key residues along the proton translocation channel. Our findings provide a detailed molecular mechanism of the dynamic couplings of Y185 and the bR photocycle from a structural perspective. The method used in this paper may be applied to the study of other microbial photoreceptors.
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6
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Dong M. A Minireview on Temperature Dependent Protein Conformational Sampling. Protein J 2021; 40:545-553. [PMID: 34181188 DOI: 10.1007/s10930-021-10012-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2021] [Indexed: 12/01/2022]
Abstract
In this minireview we discuss the role of the more subtle conformational change-protein conformational sampling and connect it to the classic relationship of protein structure and function. The theory of pre-existing functional states of protein are discussed in context of alternate protein conformational sampling. Last, we discuss how temperature, ligand binding and mutations affect the protein conformational sampling mode which is linked to the protein function regulation. The review includes several protein systems that showed temperature dependent protein conformational sampling. We also specifically included two enzyme systems, thermophilic alcohol dehydrogenase (ht-ADH) and thermolysin which we previously studied when discussing temperature dependent protein conformational sampling.
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Affiliation(s)
- Ming Dong
- Department of Chemistry, North Carolina Agricultural and Technical State University, 1601 E Market Street, Greensboro, NC, 27410, USA.
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7
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Kooijman L, Schuster M, Baumann C, Jurt S, Löhr F, Fürtig B, Güntert P, Zerbe O. Dynamics of Bacteriorhodopsin in the Dark‐Adapted State from Solution Nuclear Magnetic Resonance Spectroscopy. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Laurens Kooijman
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Matthias Schuster
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Christian Baumann
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Simon Jurt
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Frank Löhr
- Institute of Biophysical Chemistry Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt am Main Germany
| | - Boris Fürtig
- Institute of Organic Chemistry and Chemical Biology Goethe University Frankfurt Max-von-Laue-Straße 7 60438 Frankfurt am Main Germany
| | - Peter Güntert
- Institute of Biophysical Chemistry Center for Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Straße 9 60438 Frankfurt am Main Germany
- Laboratory of Physical Chemistry ETH Zürich Vladimir-Prelog-Weg 2 8093 Zurich Switzerland
| | - Oliver Zerbe
- Department of Chemistry University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
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8
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Kooijman L, Schuster M, Baumann C, Jurt S, Löhr F, Fürtig B, Güntert P, Zerbe O. Dynamics of Bacteriorhodopsin in the Dark-Adapted State from Solution Nuclear Magnetic Resonance Spectroscopy. Angew Chem Int Ed Engl 2020; 59:20965-20972. [PMID: 32726501 DOI: 10.1002/anie.202004393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 07/15/2020] [Indexed: 01/02/2023]
Abstract
To achieve efficient proton pumping in the light-driven proton pump bacteriorhodopsin (bR), the protein must be tightly coupled to the retinal to rapidly convert retinal isomerization into protein structural rearrangements. Methyl group dynamics of bR embedded in lipid nanodiscs were determined in the dark-adapted state, and were found to be mostly well ordered at the cytosolic side. Methyl groups in the M145A mutant of bR, which displays only 10 % residual proton pumping activity, are less well ordered, suggesting a link between side-chain dynamics on the cytosolic side of the bR cavity and proton pumping activity. In addition, slow conformational exchange, attributed to low frequency motions of aromatic rings, was indirectly observed for residues on the extracellular side of the bR cavity. This may be related to reorganization of the water network. These observations provide a detailed picture of previously undescribed equilibrium dynamics on different time scales for ground-state bR.
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Affiliation(s)
- Laurens Kooijman
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Matthias Schuster
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Christian Baumann
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Simon Jurt
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Frank Löhr
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt am Main, Germany
| | - Boris Fürtig
- Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt am Main, Germany
| | - Peter Güntert
- Institute of Biophysical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 9, 60438, Frankfurt am Main, Germany.,Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland
| | - Oliver Zerbe
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
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9
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Rigidity of protein structure revealed by incoherent neutron scattering. Biochim Biophys Acta Gen Subj 2020; 1864:129536. [DOI: 10.1016/j.bbagen.2020.129536] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 01/11/2020] [Accepted: 01/14/2020] [Indexed: 01/05/2023]
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10
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Abstract
AbstractThe dynamics of proteins in solution includes a variety of processes, such as backbone and side-chain fluctuations, interdomain motions, as well as global rotational and translational (i.e. center of mass) diffusion. Since protein dynamics is related to protein function and essential transport processes, a detailed mechanistic understanding and monitoring of protein dynamics in solution is highly desirable. The hierarchical character of protein dynamics requires experimental tools addressing a broad range of time- and length scales. We discuss how different techniques contribute to a comprehensive picture of protein dynamics, and focus in particular on results from neutron spectroscopy. We outline the underlying principles and review available instrumentation as well as related analysis frameworks.
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11
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Dynamical properties of myoglobin in an ultraviscous water-glycerol solvent investigated with elastic neutron scattering and FTIR spectroscopy. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.07.050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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12
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Korb JP. Multiscale nuclear magnetic relaxation dispersion of complex liquids in bulk and confinement. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 104:12-55. [PMID: 29405980 DOI: 10.1016/j.pnmrs.2017.11.001] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 10/29/2017] [Accepted: 11/01/2017] [Indexed: 06/07/2023]
Abstract
The nuclear magnetic relaxation dispersion (NMRD) technique consists of measurement of the magnetic-field dependence of the longitudinal nuclear-spin-lattice relaxation rate 1/T1. Usually, the acquisition of the NMRD profiles is made using a fast field cycling (FFC) NMR technique that varies the magnetic field and explores a very large range of Larmor frequencies (10 kHz < ω0/(2π) <40 MHz). This allows extensive explorations of the fluctuations to which nuclear spin relaxation is sensitive. The FFC technique thus offers opportunities on multiple scales of both time and distance for characterizing the molecular dynamics and transport properties of complex liquids in bulk or embedded in confined environments. This review presents the principles, theories and applications of NMRD for characterizing fundamental properties such as surface correlation times, diffusion coefficients and dynamical surface affinity (NMR wettability) for various confined liquids. The basic longitudinal and transverse relaxation equations are outlined for bulk liquids. The nuclear relaxation of a liquid confined in pores is considered in detail in order to find the biphasic fast exchange relations for a liquid at proximity of a solid surface. The physical-chemistry of liquids at solid surfaces induces striking differences between NMRD profiles of aprotic and protic (water) liquids embedded in calibrated porous disordered materials. A particular emphasis of this review concerns the extension of FFC NMR relaxation to industrial applications. For instance, it is shown that the FFC technique is sufficiently rapid for following the progressive setting of cement-based materials (plasters, cement pastes, concretes). The technique also allows studies of the dynamics of hydrocarbons in proximity of asphaltene nano-aggregates and macro-aggregates in heavy crude oils as a function of the concentration of asphaltenes. It also gives new information on the wettability of petroleum fluids (brine and oil) embedded in shale oil rocks. It is useful for understanding the relations and correlations between NMR relaxation times T1 and T2, diffusion coefficients D, and viscosity η of heavy crude oils. This is of particular importance for interpreting T1, T2, 2D T1-T2 and D-T2 correlation spectra that could be obtained down-hole, thus giving a valuable tool for investigating in situ the molecular dynamics of petroleum fluids. Another domain of interest concerns biological applications. This is of particular importance for studying the complex dynamical spectrum of a folded polymeric structure that may span many decades in frequency or time. A direct NMRD characterization of water diffusional dynamics is presented at the protein interface. NMR experiments using a shuttle technique give results well above the frequency range accessible via the FFC technique; examples of this show protein dynamics over a range from fast and localized motions to slow and delocalized collective motions involving the whole protein. This review ends by an interpretation of the origin of the proton magnetic field dependence of T1 for different biological tissues of animals; this includes a proposal for interpreting in vivo MRI data from human brain at variable magnetic fields, where the FFC relaxation analysis suggests that brain white-matter is distinct from grey-matter, in agreement with diffusion-weighted MRI imaging.
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Affiliation(s)
- Jean-Pierre Korb
- Laboratoire de Physique de la Matière Condensée, Ecole Polytechnique, CNRS, Université de Paris Saclay, 91128 Palaiseau Cedex, France; Sorbonne Universités, UPMC Univ. Paris 06, CNRS, PHENIX Laboratory, F-75005 Paris, France.
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13
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Buda F, Keijer T, Ganapathy S, de Grip WJ. A Quantum-mechanical Study of the Binding Pocket of Proteorhodopsin: Absorption and Vibrational Spectra Modulated by Analogue Chromophores. Photochem Photobiol 2017; 93:1399-1406. [DOI: 10.1111/php.12800] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 05/22/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Francesco Buda
- Leiden University; Leiden Institute of Chemistry; Leiden The Netherlands
| | - Tom Keijer
- Leiden University; Leiden Institute of Chemistry; Leiden The Netherlands
| | - Srividya Ganapathy
- Leiden University; Leiden Institute of Chemistry; Leiden The Netherlands
| | - Willem J. de Grip
- Leiden University; Leiden Institute of Chemistry; Leiden The Netherlands
- Radboud University Medical Center; Radboud Institute for Molecular Life Sciences; Nijmegen The Netherlands
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14
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15
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Zaccai G, Natali F, Peters J, Řihová M, Zimmerman E, Ollivier J, Combet J, Maurel MC, Bashan A, Yonath A. The fluctuating ribosome: thermal molecular dynamics characterized by neutron scattering. Sci Rep 2016; 6:37138. [PMID: 27849042 PMCID: PMC5111069 DOI: 10.1038/srep37138] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 10/25/2016] [Indexed: 01/08/2023] Open
Abstract
Conformational changes associated with ribosome function have been identified by X-ray crystallography and cryo-electron microscopy. These methods, however, inform poorly on timescales. Neutron scattering is well adapted for direct measurements of thermal molecular dynamics, the ‘lubricant’ for the conformational fluctuations required for biological activity. The method was applied to compare water dynamics and conformational fluctuations in the 30 S and 50 S ribosomal subunits from Haloarcula marismortui, under high salt, stable conditions. Similar free and hydration water diffusion parameters are found for both subunits. With respect to the 50 S subunit, the 30 S is characterized by a softer force constant and larger mean square displacements (MSD), which would facilitate conformational adjustments required for messenger and transfer RNA binding. It has been shown previously that systems from mesophiles and extremophiles are adapted to have similar MSD under their respective physiological conditions. This suggests that the results presented are not specific to halophiles in high salt but a general property of ribosome dynamics under corresponding, active conditions. The current study opens new perspectives for neutron scattering characterization of component functional molecular dynamics within the ribosome.
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Affiliation(s)
- Giuseppe Zaccai
- Institut Laue Langevin, F-38042 Grenoble, France.,Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 38044 Grenoble, France
| | - Francesca Natali
- Institut Laue Langevin, F-38042 Grenoble, France.,CNR-IOM, OGG, F-38042 Grenoble, France
| | - Judith Peters
- Institut Laue Langevin, F-38042 Grenoble, France.,Univ. Grenoble Alpes, LiPhy, F-38044 Grenoble, France
| | - Martina Řihová
- Institut de Systématique, Evolution, Biodiversité, ISYEB - UMR 7205- CNRS, MNHN, UPMC, EPHE UPMC, Sorbonne Universités, 57 rue Cuvier, CP 50, 75005 Paris, France.,Institute of Physics, Charles University, Faculty of Mathematics and Physics, CZ-121 16 Prague, Czech Republic
| | - Ella Zimmerman
- Weizmann Institute, Department of Structural Biology, 76100 Rehovot, Israel
| | - J Ollivier
- Institut Laue Langevin, F-38042 Grenoble, France
| | - J Combet
- Institut Laue Langevin, F-38042 Grenoble, France.,Institut Charles Sadron, CNRS-UdS, 67034 Strasbourg Cedex 2, France
| | - Marie-Christine Maurel
- Institut de Systématique, Evolution, Biodiversité, ISYEB - UMR 7205- CNRS, MNHN, UPMC, EPHE UPMC, Sorbonne Universités, 57 rue Cuvier, CP 50, 75005 Paris, France
| | - Anat Bashan
- Weizmann Institute, Department of Structural Biology, 76100 Rehovot, Israel
| | - Ada Yonath
- Weizmann Institute, Department of Structural Biology, 76100 Rehovot, Israel
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16
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Lazarova T, Mlynarczyk K, Querol E, Tenchov B, Filipek S, Padrós E. Identification of Specific Effect of Chloride on the Spectral Properties and Structural Stability of Multiple Extracellular Glutamic Acid Mutants of Bacteriorhodopsin. PLoS One 2016; 11:e0162952. [PMID: 27657718 PMCID: PMC5033488 DOI: 10.1371/journal.pone.0162952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/31/2016] [Indexed: 11/18/2022] Open
Abstract
In the present work we combine spectroscopic, DSC and computational approaches to examine the multiple extracellular Glu mutants E204Q/E194Q, E204Q/E194Q/E9Q and E204Q/E194Q/E9Q/E74Q of bacteriorhodopsin by varying solvent ionic strength and composition. Absorption spectroscopy data reveal that the absorption maxima of multiple EC Glu mutants can be tuned by the chloride concentration in the solution. Visible Circular dichroism spectra imply that the specific binding of Cl- can modulate weakened exciton chromophore coupling and reestablish wild type-like bilobe spectral features of the mutants. The DSC data display reappearance of the reversible thermal transition, higher Tm of denaturation and an increase in the enthalpy of unfolding of the mutants in 1 M KCl solutions. Molecular dynamics simulations indicate high affinity binding of Cl- to Arg82 and to Gln204 and Gln194 residues in the mutants. Analysis of the experimental data suggests that simultaneous elimination of the negatively charged side chain of Glu194 and Glu204 is the major cause for mutants' alterations. Specific Cl- binding efficiently coordinates distorted hydrogen bonding interactions of the EC region and reconstitutes the conformation and structure stability of mutated bR in WT-like fashion.
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Affiliation(s)
- Tzvetana Lazarova
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, Barcelona, Spain
- * E-mail: (TL); (EP)
| | - Krzysztof Mlynarczyk
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Enric Querol
- Institut de Biomedicina i Biotecnologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Boris Tenchov
- Department of Medical Physics and Biophysics, Faculty of Medicine, Medical University – Sofia, Sofia, Bulgaria
| | - Slawomir Filipek
- Faculty of Chemistry, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Esteve Padrós
- Unitat de Biofísica, Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, and Centre d'Estudis en Biofísica, Universitat Autònoma de Barcelona, Barcelona, Spain
- * E-mail: (TL); (EP)
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17
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Hydration of proteins and nucleic acids: Advances in experiment and theory. A review. Biochim Biophys Acta Gen Subj 2016; 1860:1821-35. [PMID: 27241846 DOI: 10.1016/j.bbagen.2016.05.036] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 05/20/2016] [Accepted: 05/26/2016] [Indexed: 11/21/2022]
Abstract
BACKGROUND Most biological processes involve water, and the interactions of biomolecules with water affect their structure, function and dynamics. SCOPE OF REVIEW This review summarizes the current knowledge of protein and nucleic acid interactions with water, with a special focus on the biomolecular hydration layer. Recent developments in both experimental and computational methods that can be applied to the study of hydration structure and dynamics are reviewed, including software tools for the prediction and characterization of hydration layer properties. MAJOR CONCLUSIONS In the last decade, important advances have been made in our understanding of the factors that determine how biomolecules and their aqueous environment influence each other. Both experimental and computational methods contributed to the gradually emerging consensus picture of biomolecular hydration. GENERAL SIGNIFICANCE An improved knowledge of the structural and thermodynamic properties of the hydration layer will enable a detailed understanding of the various biological processes in which it is involved, with implications for a wide range of applications, including protein-structure prediction and structure-based drug design.
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Grimaldo M, Roosen-Runge F, Hennig M, Zanini F, Zhang F, Jalarvo N, Zamponi M, Schreiber F, Seydel T. Hierarchical molecular dynamics of bovine serum albumin in concentrated aqueous solution below and above thermal denaturation. Phys Chem Chem Phys 2016; 17:4645-55. [PMID: 25587698 DOI: 10.1039/c4cp04944f] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of proteins in solution is a complex and hierarchical process, affected by the aqueous environment as well as temperature. We present a comprehensive study on nanosecond time and nanometer length scales below, at, and above the denaturation temperature Td. Our experimental data evidence dynamical processes in protein solutions on three distinct time scales. We suggest a consistent physical picture of hierarchical protein dynamics: (i) self-diffusion of the entire protein molecule is confirmed to agree with colloid theory for all temperatures where the protein is in its native conformational state. At higher temperatures T > Td, the self-diffusion is strongly obstructed by cross-linking or entanglement. (ii) The amplitude of backbone fluctuations grows with increasing T, and a transition in its dynamics is observed above Td. (iii) The number of mobile side-chains increases sharply at Td while their average dynamics exhibits only little variations. The combination of quasi-elastic neutron scattering and the presented analytical framework provides a detailed microscopic picture of the protein molecular dynamics in solution, thereby reflecting the changes of macroscopic properties such as cluster formation and gelation.
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Affiliation(s)
- Marco Grimaldo
- Institut Max von Laue - Paul Langevin (ILL), CS 20156, F-38042 Grenoble, France.
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19
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Haertlein M, Moulin M, Devos JM, Laux V, Dunne O, Trevor Forsyth V. Biomolecular Deuteration for Neutron Structural Biology and Dynamics. Methods Enzymol 2016; 566:113-57. [DOI: 10.1016/bs.mie.2015.11.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Lenton S, Seydel T, Nylander T, Holt C, Härtlein M, Teixeira S, Zaccai G. Dynamic footprint of sequestration in the molecular fluctuations of osteopontin. J R Soc Interface 2015; 12:0506. [PMID: 26354827 PMCID: PMC4614460 DOI: 10.1098/rsif.2015.0506] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/19/2015] [Indexed: 11/12/2022] Open
Abstract
The sequestration of calcium phosphate by unfolded proteins is fundamental to the stabilization of biofluids supersaturated with respect to hydroxyapatite, such as milk, blood or urine. The unfolded state of osteopontin (OPN) is thought to be a prerequisite for this activity, which leads to the formation of core-shell calcium phosphate nanoclusters. We report on the structures and dynamics of a native OPN peptide from bovine milk, studied by neutron spectroscopy and small-angle X-ray and neutron scattering. The effects of sequestration are quantified on the nanosecond- ångström resolution by elastic incoherent neutron scattering. The molecular fluctuations of the free phosphopeptide are in agreement with a highly flexible protein. An increased resilience to diffusive motions of OPN is corroborated by molecular fluctuations similar to those observed for globular proteins, yet retaining conformational flexibilities. The results bring insight into the modulation of the activity of OPN and phosphopeptides with a role in the control of biomineralization. The quantification of such effects provides an important handle for the future design of new peptides based on the dynamics-activity relationship.
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Affiliation(s)
- S Lenton
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France Environment, Physical Sciences and Applied Mathematics Research Institute, Keele University, Staffordshire ST5 5BG, UK
| | - T Seydel
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France
| | - T Nylander
- Division of Physical Chemistry, Lund University, PO Box 124, 221 00 Lund, Sweden
| | - C Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, UK
| | - M Härtlein
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France
| | - S Teixeira
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France Environment, Physical Sciences and Applied Mathematics Research Institute, Keele University, Staffordshire ST5 5BG, UK
| | - G Zaccai
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France C.N.R.S., Institut de Biologie Structurale, F-38044 Grenoble, France
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21
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Chu X, Wang J. Specificity and affinity quantification of flexible recognition from underlying energy landscape topography. PLoS Comput Biol 2014; 10:e1003782. [PMID: 25144525 PMCID: PMC4140643 DOI: 10.1371/journal.pcbi.1003782] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Accepted: 06/25/2014] [Indexed: 01/07/2023] Open
Abstract
Flexibility in biomolecular recognition is essential and critical for many cellular activities. Flexible recognition often leads to moderate affinity but high specificity, in contradiction with the conventional wisdom that high affinity and high specificity are coupled. Furthermore, quantitative understanding of the role of flexibility in biomolecular recognition is still challenging. Here, we meet the challenge by quantifying the intrinsic biomolecular recognition energy landscapes with and without flexibility through the underlying density of states. We quantified the thermodynamic intrinsic specificity by the topography of the intrinsic binding energy landscape and the kinetic specificity by association rate. We found that the thermodynamic and kinetic specificity are strongly correlated. Furthermore, we found that flexibility decreases binding affinity on one hand, but increases binding specificity on the other hand, and the decreasing or increasing proportion of affinity and specificity are strongly correlated with the degree of flexibility. This shows more (less) flexibility leads to weaker (stronger) coupling between affinity and specificity. Our work provides a theoretical foundation and quantitative explanation of the previous qualitative studies on the relationship among flexibility, affinity and specificity. In addition, we found that the folding energy landscapes are more funneled with binding, indicating that binding helps folding during the recognition. Finally, we demonstrated that the whole binding-folding energy landscapes can be integrated by the rigid binding and isolated folding energy landscapes under weak flexibility. Our results provide a novel way to quantify the affinity and specificity in flexible biomolecular recognition. Flexibility in biomolecular recognition is crucial for the function. Flexibility often leads to moderate binding affinity but high binding specificity, challenging the conventional wisdom that high specificity is guaranteed by high affinity. Currently, understanding of the relationship between affinity and specificity in flexible biomolecular recognition is still obscure, even in a qualitative way. By exploring the intrinsic biomolecular recognition energy landscapes, we provided a novel way to quantify the thermodynamic intrinsic specificity by energy landscape topography and kinetic specificity by association rate. We show quantitatively that flexibility decreases binding affinity while increases binding specificity, and the relative changes in affinity and specificity are strongly correlated with the degree of flexibility. Our results show that more (less) flexibility leads to weaker (stronger) coupling between affinity and specificity. Importantly, we demonstrated that flexibility modulates affinity and specificity through the underlying energy landscape. Our study establishes the quantitative relationship among flexibility, affinity and specificity, bridging the gap between theory and experiments.
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Affiliation(s)
- Xiakun Chu
- College of Physics, Jilin University, Changchun, Jilin, P. R. China
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, P. R. China
| | - Jin Wang
- College of Physics, Jilin University, Changchun, Jilin, P. R. China
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, P. R. China
- Department of Chemistry and Physics, State University of New York at Stony Brook, Stony Brook, New York, United States of America
- * E-mail:
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22
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Callaway DJE, Farago B, Bu Z. Nanoscale protein dynamics: a new frontier for neutron spin echo spectroscopy. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:76. [PMID: 23884624 DOI: 10.1140/epje/i2013-13076-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 12/16/2012] [Accepted: 01/02/2013] [Indexed: 06/02/2023]
Abstract
Recent studies show that neutron spin echo spectroscopy (NSE) can reveal long-range protein domain motions on nanometer lengthscales and on nanosecond to microsecond timescales. This unique capability of NSE provides new opportunities to understand protein dynamics and functions, such as how binding signals are propagated in a protein to distal sites. Here we review our applications of NSE to the study of nanoscale protein domain motions in a set of cell signaling proteins. We summarize the theoretical framework we have developed, which allows one to interpret the NSE data (Biophys. J. 99, 3473 (2010) and Proc. Natl. Acad. Sci. USA 102, 17646 (2005)). Our theoretical framework uses simple concepts from nonequilibrium statistical mechanics, and does not require elaborate molecular dynamics simulations, complex fits to rotational motion, or elastic network models. It is thus more robust than multiparameter techniques that require untestable assumptions. We also demonstrate our experimental scheme involving deuterium labeling of a protein domain or a subunit in a protein complex. We show that our selective deuteration scheme can highlight and resolve specific domain dynamics from the abundant global translational and rotational motions in a protein. Our approach thus clears significant hurdles to the application of NSE for the study of protein dynamics in solution.
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Affiliation(s)
- David J E Callaway
- Department of Chemistry, the City College of New York, New York, NY 10031, USA.
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23
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Miao Y, Hong L, Yi Z, Smith JC. Zaccai neutron resilience and site-specific hydration dynamics in a globular protein. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2013; 36:72. [PMID: 23852576 DOI: 10.1140/epje/i2013-13072-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 01/18/2013] [Accepted: 02/20/2013] [Indexed: 06/02/2023]
Abstract
A discussion is presented of contributions of the Zaccai group to the understanding of flexibility in biological macromolecules using dynamic neutron scattering. The concept of resilience as introduced by Zaccai is discussed and investigated using molecular dynamics simulation on camphor-bound cytochrome P450. The resilience of hydrophilic residues is found to be more strongly affected by hydration than that of hydrophobic counterparts. The hydration-induced softening of protein propagates from the surface into the dry core. Moreover, buried hydrophilic residues behave more like those exposed on the protein surface, and are different from their hydrophobic counterparts.
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Affiliation(s)
- Yinglong Miao
- University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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24
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Ngai KL, Capaccioli S, Paciaroni A. Change of caged dynamics at Tg in hydrated proteins: Trend of mean squared displacements after correcting for the methyl-group rotation contribution. J Chem Phys 2013; 138:235102. [DOI: 10.1063/1.4810752] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Quantifying the topography of the intrinsic energy landscape of flexible biomolecular recognition. Proc Natl Acad Sci U S A 2013; 110:E2342-51. [PMID: 23754431 DOI: 10.1073/pnas.1220699110] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Biomolecular functions are determined by their interactions with other molecules. Biomolecular recognition is often flexible and associated with large conformational changes involving both binding and folding. However, the global and physical understanding for the process is still challenging. Here, we quantified the intrinsic energy landscapes of flexible biomolecular recognition in terms of binding-folding dynamics for 15 homodimers by exploring the underlying density of states, using a structure-based model both with and without considering energetic roughness. By quantifying three individual effective intrinsic energy landscapes (one for interfacial binding, two for monomeric folding), the association mechanisms for flexible recognition of 15 homodimers can be classified into two-state cooperative "coupled binding-folding" and three-state noncooperative "folding prior to binding" scenarios. We found that the association mechanism of flexible biomolecular recognition relies on the interplay between the underlying effective intrinsic binding and folding energy landscapes. By quantifying the whole global intrinsic binding-folding energy landscapes, we found strong correlations between the landscape topography measure Λ (dimensionless ratio of energy gap versus roughness modulated by the configurational entropy) and the ratio of the thermodynamic stable temperature versus trapping temperature, as well as between Λ and binding kinetics. Therefore, the global energy landscape topography determines the binding-folding thermodynamics and kinetics, crucial for the feasibility and efficiency of realizing biomolecular function. We also found "U-shape" temperature-dependent kinetic behavior and a dynamical cross-over temperature for dividing exponential and nonexponential kinetics for two-state homodimers. Our study provides a unique way to bridge the gap between theory and experiments.
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26
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Yi Z, Miao Y, Baudry J, Jain N, Smith JC. Derivation of mean-square displacements for protein dynamics from elastic incoherent neutron scattering. J Phys Chem B 2012; 116:5028-36. [PMID: 22471396 DOI: 10.1021/jp2102868] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The derivation of mean-square displacements from elastic incoherent neutron scattering (EINS) of proteins is examined, with the aid of experiments on camphor-bound cytochrome P450cam and complementary molecular dynamics simulations. It is shown that a q(4) correction to the elastic incoherent structure factor (where q is the scattering vector) can be simply used to reliably estimate from the experiment both the average mean-square atomic displacement, <Δr(2)> of the nonexchanged hydrogen atoms in the protein and its variance, σ(2). The molecular dynamics simulation results are in broad agreement with the experimentally derived <Δr(2)> and σ(2) derived from EINS on instruments at two different energy resolutions, corresponding to dynamics on the ∼100 ps and ∼1 ns time scales. Significant dynamical heterogeneity is found to arise from methyl-group rotations. The easy-to-apply q(4) correction extends the information extracted from elastic incoherent neutron scattering experiments and should be of wide applicability.
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Affiliation(s)
- Zheng Yi
- University of Tennessee/Oak Ridge National Laboratory Center for Molecular Biophysics , P.O. Box 2008, 1 Bethel Valley Road, Oak Ridge, Tennessee 37831, United States
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27
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Nagy G, Pieper J, Krumova SB, Kovács L, Trapp M, Garab G, Peters J. Dynamic properties of photosystem II membranes at physiological temperatures characterized by elastic incoherent neutron scattering. Increased flexibility associated with the inactivation of the oxygen evolving complex. PHOTOSYNTHESIS RESEARCH 2012; 111:113-24. [PMID: 22052408 DOI: 10.1007/s11120-011-9701-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 10/13/2011] [Indexed: 05/02/2023]
Abstract
Elastic incoherent neutron scattering (EINS), a non-invasive technique which is capable of measuring the mean square displacement of atoms in the sample, has been widely used in biology for exploring the dynamics of proteins and lipid membranes but studies on photosynthetic systems are scarce. In this study we investigated the dynamic characteristics of Photosystem II (PSII) membrane fragments between 280 and 340 K, i.e., in the physiological temperature range and in the range of thermal denaturation of some of the protein complexes. The mean square displacement values revealed the presence of a hydration-sensitive transition in the sample between 310 and 320 K, suggesting that the oxygen evolving complex (OEC) plays an important role in the transition. Indeed, in samples in which the OEC had been removed by TRIS- or heat-treatments (323 and 333 K) no such transition was found. Further support on the main role of OEC in these reorganizations is provided by data obtained from differential scanning calorimetry experiments, showing marked differences between the untreated and TRIS-treated samples. In contrast, circular dichroism spectra exhibited only minor changes in the excitonic interactions below 323 K, showing that the molecular organization of the pigment-protein complexes remains essentially unaffected. Our data, along with earlier incoherent neutron scattering data on PSII membranes at cryogenic temperatures (Pieper et al., Biochemistry 46:11398-11409, 2007), demonstrate that this technique can be applied to characterize the dynamic features of PSII membranes, and can be used to investigate photosynthetic membranes under physiologically relevant experimental conditions.
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Affiliation(s)
- Gergely Nagy
- Institut Laue-Langevin, P.O. Box 156, 38042, Grenoble Cedex 9, France
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28
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Capaccioli S, Ngai KL, Ancherbak S, Paciaroni A. Evidence of Coexistence of Change of Caged Dynamics at Tg and the Dynamic Transition at Td in Solvated Proteins. J Phys Chem B 2012; 116:1745-57. [DOI: 10.1021/jp2057892] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. Capaccioli
- CNR-IPCF, Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici,
c/o Dipartimento di Fisica, Largo Bruno Pontecorvo 3, I-56127 Pisa,
Italy
- Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3,
I-56127 Pisa, Italy
| | - K. L. Ngai
- CNR-IPCF, Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici,
c/o Dipartimento di Fisica, Largo Bruno Pontecorvo 3, I-56127 Pisa,
Italy
| | - S. Ancherbak
- Dipartimento di Fisica, Università di Pisa, Largo Bruno Pontecorvo 3,
I-56127 Pisa, Italy
| | - A. Paciaroni
- Dipartimento di Fisica, Università di Perugia & IOM-CNR, Via A. Pascoli 1, 06123 Perugia, Italy
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29
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Ruvinsky AM, Vakser IA. Sequence composition and environment effects on residue fluctuations in protein structures. J Chem Phys 2011; 133:155101. [PMID: 20969427 DOI: 10.1063/1.3498743] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Structure fluctuations in proteins affect a broad range of cell phenomena, including stability of proteins and their fragments, allosteric transitions, and energy transfer. This study presents a statistical-thermodynamic analysis of relationship between the sequence composition and the distribution of residue fluctuations in protein-protein complexes. A one-node-per-residue elastic network model accounting for the nonhomogeneous protein mass distribution and the interatomic interactions through the renormalized inter-residue potential is developed. Two factors, a protein mass distribution and a residue environment, were found to determine the scale of residue fluctuations. Surface residues undergo larger fluctuations than core residues in agreement with experimental observations. Ranking residues over the normalized scale of fluctuations yields a distinct classification of amino acids into three groups: (i) highly fluctuating-Gly, Ala, Ser, Pro, and Asp, (ii) moderately fluctuating-Thr, Asn, Gln, Lys, Glu, Arg, Val, and Cys, and (iii) weakly fluctuating-Ile, Leu, Met, Phe, Tyr, Trp, and His. The structural instability in proteins possibly relates to the high content of the highly fluctuating residues and a deficiency of the weakly fluctuating residues in irregular secondary structure elements (loops), chameleon sequences, and disordered proteins. Strong correlation between residue fluctuations and the sequence composition of protein loops supports this hypothesis. Comparing fluctuations of binding site residues (interface residues) with other surface residues shows that, on average, the interface is more rigid than the rest of the protein surface and Gly, Ala, Ser, Cys, Leu, and Trp have a propensity to form more stable docking patches on the interface. The findings have broad implications for understanding mechanisms of protein association and stability of protein structures.
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Affiliation(s)
- Anatoly M Ruvinsky
- Center for Bioinformatics, The University of Kansas, Lawrence, Kansas 66047, USA.
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30
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Wood K, Tobias DJ, Kessler B, Gabel F, Oesterhelt D, Mulder FAA, Zaccai G, Weik M. The low-temperature inflection observed in neutron scattering measurements of proteins is due to methyl rotation: direct evidence using isotope labeling and molecular dynamics simulations. J Am Chem Soc 2010; 132:4990-1. [PMID: 20302295 DOI: 10.1021/ja910502g] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is increasing interest in the contribution of methyl groups to the overall dynamics measured by neutron scattering experiments of proteins. In particular an inflection observed in atomic mean square displacements measured as a function of temperature on high resolution spectrometers (approximately 1 microeV) was explained by the onset of methyl group rotations. By specifically labeling a non-methyl-containing side-chain in a native protein system, the purple membrane, and performing neutron scattering measurements, we here provide direct experimental evidence that the observed inflection is indeed due to methyl group rotations. Molecular dynamics simulations reproduce the experimental data, and their analysis suggests that the apparent transition is due to methyl group rotation entering the finite instrumental resolution of the spectrometer. Methyl group correlation times measured by solid state NMR in the purple membrane, taken from previous work, support the interpretation.
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Nakagawa H, Kamikubo H, Kataoka M. Effect of conformational states on protein dynamical transition. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:27-33. [DOI: 10.1016/j.bbapap.2009.06.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/10/2009] [Accepted: 06/29/2009] [Indexed: 10/20/2022]
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Varga B, Migliardo F, Takacs E, Vertessy B, Magazù S, Telling MTF. Study of solvent-protein coupling effects by neutron scattering. J Biol Phys 2009; 36:207-20. [PMID: 19795216 DOI: 10.1007/s10867-009-9177-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 09/09/2009] [Indexed: 11/30/2022] Open
Abstract
The present work aims to characterize the dynamical behavior of proteins immersed in bio-preserving liquids and glasses. For this purpose, the protein dUTPase was chosen, while the selected solvents were glycerol, a triol, and some homologous disaccharides, i.e., trehalose, maltose, and sucrose, which are known to be very effective bio-preserving agents. The results highlight that the disaccharides show a slowing down effect on the water dynamics, which is stronger for trehalose than in the case of the other disaccharides. Furthermore, a characterization of the medium which hosts the protein is performed by using an operative definition of fragility based on the mean square displacement extracted by elastic incoherent neutron scattering, which is directly connected to Angell's kinetic fragility based on the viscosity. Finally, a study of the dynamics of the protein sequestered within the solvents is performed. The result shows that the protein dynamics is coupled with that of the surrounding matrix.
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33
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From powder to solution: hydration dependence of human hemoglobin dynamics correlated to body temperature. Biophys J 2009; 96:5073-81. [PMID: 19527667 DOI: 10.1016/j.bpj.2009.03.043] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Revised: 02/25/2009] [Accepted: 03/30/2009] [Indexed: 11/23/2022] Open
Abstract
A transition in hemoglobin (Hb), involving partial unfolding and aggregation, has been shown previously by various biophysical methods. The correlation between the transition temperature and body temperature for Hb from different species, suggested that it might be significant for biological function. To focus on such biologically relevant human Hb dynamics, we studied the protein internal picosecond motions as a response to hydration, by elastic and quasielastic neutron scattering. Rates of fast diffusive motions were found to be significantly enhanced with increasing hydration from fully hydrated powder to concentrated Hb solution. In concentrated protein solution, the data showed that amino acid side chains can explore larger volumes above body temperature than expected from normal temperature dependence. The body temperature transition in protein dynamics was absent in fully hydrated powder, indicating that picosecond protein dynamics responsible for the transition is activated only at a sufficient level of hydration. A collateral result from the study is that fully hydrated protein powder samples do not accurately describe all aspects of protein picosecond dynamics that might be necessary for biological function.
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Rueda M, Bottegoni G, Abagyan R. Consistent improvement of cross-docking results using binding site ensembles generated with elastic network normal modes. J Chem Inf Model 2009; 49:716-25. [PMID: 19434904 DOI: 10.1021/ci8003732] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The representation of protein flexibility is still a challenge for the state-of-the-art flexible ligand docking protocols. In this article, we use a large and diverse benchmark to prove that is possible to improve consistently the cross-docking performance against a single receptor conformation, using an equilibrium ensemble of binding site conformers. The benchmark contained 28 proteins, and our method predicted the top-ranked near native ligand poses 20% more efficiently than using a single receptor. The multiple conformations were derived from the collective variable space defined by all heavy-atom elastic network normal modes, including backbone and side chains. We have found that the binding site displacements for best positioning of the ligand seem rather independent from the global collective motions of the protein. We also found that the number of binding site conformations needed to represent nonredundant flexibility was < 100. The ensemble of receptor conformations can be generated at our Web site at http://abagyan.scripps.edu/MRC.
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Affiliation(s)
- Manuel Rueda
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, Mail TPC-28, La Jolla, California 92037, USA
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35
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Schulz R, Krishnan M, Daidone I, Smith JC. Instantaneous normal modes and the protein glass transition. Biophys J 2009; 96:476-84. [PMID: 19167298 DOI: 10.1016/j.bpj.2008.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 10/15/2008] [Indexed: 11/29/2022] Open
Abstract
In the instantaneous normal mode method, normal mode analysis is performed at instantaneous configurations of a condensed-phase system, leading to modes with negative eigenvalues. These negative modes provide a means of characterizing local anharmonicities of the potential energy surface. Here, we apply instantaneous normal mode to analyze temperature-dependent diffusive dynamics in molecular dynamics simulations of a small protein (a scorpion toxin). Those characteristics of the negative modes are determined that correlate with the dynamical (or glass) transition behavior of the protein, as manifested as an increase in the gradient with T of the average atomic mean-square displacement at approximately 220 K. The number of negative eigenvalues shows no transition with temperature. Further, although filtering the negative modes to retain only those with eigenvectors corresponding to double-well potentials does reveal a transition in the hydration water, again, no transition in the protein is seen. However, additional filtering of the protein double-well modes, so as to retain only those that, on energy minimization, escape to different regions of configurational space, finally leads to clear protein dynamical transition behavior. Partial minimization of instantaneous configurations is also found to remove nondiffusive imaginary modes. In summary, examination of the form of negative instantaneous normal modes is shown to furnish a physical picture of local diffusive dynamics accompanying the protein glass transition.
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Affiliation(s)
- Roland Schulz
- University of Tennessee/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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Turner GJ, Chittiboyina S, Pohren L, Hines KG, Correia JJ, Mitchell DC. The bacteriorhodopsin carboxyl-terminus contributes to proton recruitment and protein stability. Biochemistry 2009; 48:1112-22. [PMID: 19140737 DOI: 10.1021/bi801799j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We examined functional and structural roles for the bacteriorhodopsin (bR) carboxyl-terminus. The extramembranous and intracellular carboxyl-terminus was deleted by insertion of premature translation stop codons. Deletion of the carboxyl-terminus had no effect on purple membrane (PM) lattice dimensions, sheet size, or the electrogenic environment of the ground-state chromophore. Removal of the distal half of the carboxyl-terminus had no effect on light-activated proton pumping, however, truncation of the entire carboxyl-terminus accelerated the rates of M-state decay and proton uptake approximately 3.7-fold and severely distorted the kinetics of proton uptake. Differential scanning calorimetry (DSC) and SDS denaturation demonstrated that removal of the carboxyl-terminus decreased protein stability. The DSC melting temperature was lowered by 6 degrees C and the calorimetric enthalpy reduced by 50% following removal of the carboxyl-terminus. Over the time range of milliseconds to hours at least 3 phases were required to describe the SDS denaturation kinetics for each bR construction. The fastest phases were indistinguishable for all bR's, and reflected PM solubilization. At pH 7.4, 20 degrees C, and in 0.3% SDS (w/v) the half-times of bR denaturation were 19.2 min for the wild-type, 12.0 min for the half-truncation and 3.6 min for the full-truncation. Taken together the results of this study suggest that the bR ground state exhibits two "domains" of stability: (1) a core chromophore binding pocket domain that is insensitive to carboxyl-terminal interactions and (2) the surrounding helical bundle whose contributions to protein stability and proton pumping are influenced by long-range interactions with the extramembranous carboxyl-terminus.
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Affiliation(s)
- George J Turner
- Department of Chemistry and Biochemistry, Seton Hall University, South Orange, New Jersey 07079, USA.
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37
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Teixeira SCM, Ankner J, Bellissent-Funel MC, Bewley R, Blakeley MP, Coates L, Dahint R, Dalgliesh R, Dencher N, Dhont J, Fischer P, Forsyth VT, Fragneto G, Frick B, Geue T, Gilles R, Gutberlet T, Haertlein M, Hauß T, Häußler W, Heller WT, Herwig K, Holderer O, Juranyi F, Kampmann R, Knott R, Kohlbrecher J, Kreuger S, Langan P, Lechner R, Lynn G, Majkrzak C, May R, Meilleur F, Mo Y, Mortensen K, Myles DAA, Natali F, Neylon C, Niimura N, Ollivier J, Ostermann A, Peters J, Pieper J, Rühm A, Schwahn D, Shibata K, Soper AK, Straessle T, Suzuki UI, Tanaka I, Tehei M, Timmins P, Torikai N, Unruh T, Urban V, Vavrin R, Weiss K, Zaccai G. New sources and instrumentation for neutrons in biology. Chem Phys 2009; 345:133-151. [PMID: 19132140 PMCID: PMC2614686 DOI: 10.1016/j.chemphys.2008.02.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Neutron radiation offers significant advantages for the study of biological molecular structure and dynamics. A broad and significant effort towards instrumental and methodological development to facilitate biology experiments at neutron sources worldwide is reviewed.
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Affiliation(s)
- S C M Teixeira
- Institut Laue Langevin, 6 rue Jules Horowitz, 38042 Grenoble cedex 9, France
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38
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Meilleur F, Weiss KL, Myles DAA. Deuterium labeling for neutron structure-function-dynamics analysis. Methods Mol Biol 2009; 544:281-292. [PMID: 19488706 DOI: 10.1007/978-1-59745-483-4_18] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Neutron scattering and diffraction provide detailed information on the structure and dynamics of biological materials across time and length scales that range from picoseconds to nanoseconds and from 1 to 10,000 A, respectively. The particular sensitivity of neutrons to the isotopes of hydrogen makes selective deuterium labeling of biological systems an essential tool for maximizing the return from neutron scattering experiments. In neutron protein crystallography, the use of fully deuterated protein crystals improves the signal-to-noise ratio of the data by an order of magnitude and enhances the visibi-lity of the molecular structure (Proc Natl Acad Sci U S A 97:3872-3877, 2000; Acta Crystallogr D Biol Crystallogr 61:1413-1417, 2005; Acta Crystallogr D Biol Crystallogr 61:539-544, 2005). In solution and surface scattering experiments, the incorporation of deuterium-labeled subunits or components into complex assemblies or structures makes it possible to deconvolute the scattering of the labeled and unlabeled subunits and to determine their relative dispositions within the complex (J Mol Biol 93:255-265, 1975). With multiple labeling patterns, it is also possible to reconstruct the locations of multiple subunits in ternary and higher-order complexes (Science 238:1403-1406, 1987; J Mol Biol 271:588-601, 1997; J Biol Chem 275:14432-14439, 2000; Biochemistry 42:7790-7800, 2003). In inelastic neutron scattering experiments, which probe hydrogen dynamics in biological materials, the application of site, residue, or region-specific hydrogen-deuterium-labeling patterns can be used to distinguish and highlight the specific dynamics within a system (Proc Natl Acad Sci U S A 95:4970-4975, 1998).Partial, selective, or fully deuterated proteins can be readily produced by endogenous expression of recombinant proteins in bacterial systems that are adapted to growth in D(2)O solution and using selectively deuterated carbon sources. Adaptation can be achieved either by gradual step-wise increase in D(2)O concentration or, more directly, by plating cells on media of choice and selecting colonies that perform best for subsequent culture and inoculation. Scale-up growth and expression is typically performed in standard shaker flasks using either commercial or "home-grown" rich media (derived, for example, from cell lysates produced from algae grown in D(2)O) or under more controlled conditions in defined minimal media. Cell growth is typically slower in deuterated media (>5 times slower) and yields are correspondingly lower. Once the target protein has been expressed, purification proceeds by the protocols developed for the hydrogenated protein. The deuteration levels of the final product are determined by mass spectrometry.
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Affiliation(s)
- Flora Meilleur
- Department of Molecular & Structural Biochemistry, North Carolina State University, Oak Ridge National Laboratory, Raleigh, Oak Ridge, NC, TN, USA
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39
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Stadler AM, Digel I, Artmann GM, Embs JP, Zaccai G, Büldt G. Hemoglobin dynamics in red blood cells: correlation to body temperature. Biophys J 2008; 95:5449-61. [PMID: 18708462 PMCID: PMC2586580 DOI: 10.1529/biophysj.108.138040] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A transition in hemoglobin behavior at close to body temperature has been discovered recently by micropipette aspiration experiments on single red blood cells (RBCs) and circular dichroism spectroscopy on hemoglobin solutions. The transition temperature was directly correlated to the body temperatures of a variety of species. In an exploration of the molecular basis for the transition, we present neutron scattering measurements of the temperature dependence of hemoglobin dynamics in whole human RBCs in vivo. The data reveal a change in the geometry of internal protein motions at 36.9 degrees C, at human body temperature. Above that temperature, amino acid side-chain motions occupy larger volumes than expected from normal temperature dependence, indicating partial unfolding of the protein. Global protein diffusion in RBCs was also measured and the findings compared favorably with theoretical predictions for short-time self-diffusion of noncharged hard-sphere colloids. The results demonstrated that changes in molecular dynamics in the picosecond time range and angstrom length scale might well be connected to a macroscopic effect on whole RBCs that occurs at body temperature.
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40
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Ormos P. Dynamic fluctuation of proteins watched in real time. HFSP JOURNAL 2008; 2:297-301. [PMID: 19436491 DOI: 10.2976/1.2978985] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Indexed: 11/19/2022]
Abstract
The dynamic nature of protein function is a fundamental concept in the physics of proteins. Although the basic general ideas are well accepted most experimental evidence has an indirect nature. The detailed characterization of the dynamics is necessary for the understanding in detail. The dynamic fluctuations thought crucial for the function span an extremely broad time, starting from the picosecond regime. Recently, a few new experimental techniques emerged that permit the observation of dynamical phenomena directly. Notably, pulsed infrared (IR) spectroscopy has been applied with great success to observe structural changes with picosecond time resolution. Using two-dimensional-IR vibrational echo chemical exchange spectroscopy Ishikawa and co-workers [Ishikawa et al. (2008), Proc. Natl. Acad. Sci. U.S.A. 101, 14402-14407] managed to observe the transition between well defined conformational substrates of carbonmonoxy myoglobin directly. This is an important step in improving our insight into the details of protein function.
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Affiliation(s)
- Pál Ormos
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt 62. H-6726 Szeged, Hungary
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41
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Picometer-scale conformational heterogeneity separates functional from nonfunctional states of a photoreceptor protein. Structure 2008; 16:863-72. [PMID: 18547519 DOI: 10.1016/j.str.2008.02.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 02/27/2008] [Accepted: 02/27/2008] [Indexed: 11/23/2022]
Abstract
Protein structural fluctuations occur over a wide spatial scale, ranging from minute, picometer-scale displacements, to large, interdomain motions and partial unfolding. While large-scale protein structural changes and their effects on protein function have been the focus of much recent attention, small-scale fluctuations have been less well studied, and are generally assumed to have proportionally smaller effects. Here we use the bacterial photoreceptor photoactive yellow protein (PYP) to test if subtle structural changes do, indeed, imply equally subtle functional effects. We flash froze crystals of PYP to trap the protein's conformational ensemble, and probed the molecules in this ensemble for their ability to facilitate PYP's biological function (i.e., light-driven isomerization of its chromophore). Our results indicate that the apparently homogeneous structural state observed in a 0.82 A crystal structure in fact comprises an ensemble of conformational states, in which subpopulations with nearly identical structures display dramatically different functional properties.
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42
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Tatke SS, Loong CK, D'Souza N, Schoephoerster RT, Prabhakaran M. Large scale motions in a biosensor protein glucose oxidase: a combined approach by QENS, normal mode analysis, and molecular dynamics studies. Biopolymers 2008; 89:582-94. [PMID: 18273893 DOI: 10.1002/bip.20956] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The characteristics of the glucose oxidase were studied using a combination of experimental and theoretical techniques. Quasi elastic neutron scattering experiments were used to obtain the vibrational frequencies of the protein. These were compared to theoretical results obtained by normal mode analysis. Results indicate a good match between the experimental and theoretical values. Molecular dynamic simulation with covariant analysis was used to study the structure and dynamics of glucose oxidase. Various parameters like the radius of gyration, root mean square fluctuations, solvent accessibility were studied for evaluating the structural stability of the protein. The frequency of vibration calculated from the three methods is used to derive the large scale motions. Theses studies were used to predict the suitable lysine residues for linkage with carbon nanotubes.
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Affiliation(s)
- Sujit S Tatke
- Biomedical Engineering Department, FL International University, Miami, FL, USA
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43
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Telling MTF, Neylon C, Kilcoyne SH, Arrighi V. Anharmonic Behavior in the Multisubunit Protein Apoferritin as Revealed by Quasi-Elastic Neutron Scattering. J Phys Chem B 2008; 112:10873-8. [DOI: 10.1021/jp801779x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark. T. F. Telling
- ISIS Facility, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Chilton, OX11 OQX, U.K., Institute for Materials Research, University of Salford, Salford, M5 4WT U.K., and School of EPS—Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS, U.K
| | - Cameron Neylon
- ISIS Facility, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Chilton, OX11 OQX, U.K., Institute for Materials Research, University of Salford, Salford, M5 4WT U.K., and School of EPS—Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS, U.K
| | - Susan H. Kilcoyne
- ISIS Facility, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Chilton, OX11 OQX, U.K., Institute for Materials Research, University of Salford, Salford, M5 4WT U.K., and School of EPS—Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS, U.K
| | - Valeria Arrighi
- ISIS Facility, Science and Technology Facilities Council (STFC), Rutherford Appleton Laboratory, Chilton, OX11 OQX, U.K., Institute for Materials Research, University of Salford, Salford, M5 4WT U.K., and School of EPS—Chemistry, Heriot-Watt University, Edinburgh, EH14 4AS, U.K
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44
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Role of extracellular glutamic acids in the stability and energy landscape of bacteriorhodopsin. Biophys J 2008; 95:3407-18. [PMID: 18621827 DOI: 10.1529/biophysj.108.131904] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bacteriorhodopsin (BR), a specialized nanomachine, converts light energy into a proton gradient to power Halobacterium salinarum. In this work, we analyze the mechanical stability of a BR triple mutant in which three key extracellular residues, Glu(9), Glu(194), and Glu(204), were mutated simultaneously to Gln. These three Glu residues are involved in a network of hydrogen bonds, in cation binding, and form part of the proton release pathway of BR. Changes in these features and the robust photocycle dynamics of wild-type (WT) BR are apparent when the three extracellular Glu residues are mutated to Gln. It is speculated that such functional changes of proteins go hand in hand with changes in their mechanical properties. Here, we apply single-molecule dynamic force spectroscopy to investigate how the Glu to Gln mutations change interactions, reaction pathways, and the energy barriers of the structural regions of WT BR. The altered heights and positions of individual energy barriers unravel the changes in the mechanical and the unfolding kinetic properties of the secondary structures of WT BR. These changes in the mechanical unfolding energy landscape cause the proton pump to choose unfolding pathways differently. We suggest that, in a similar manner, the changed mechanical properties of mutated BR alter the functional energy landscape favoring different reaction pathways in the light-induced proton pumping mechanism.
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45
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Fujiwara S, Plazanet M, Matsumoto F, Oda T. Differences in internal dynamics of actin under different structural states detected by neutron scattering. Biophys J 2008; 94:4880-9. [PMID: 18326640 PMCID: PMC2397340 DOI: 10.1529/biophysj.107.125302] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 02/08/2008] [Indexed: 11/18/2022] Open
Abstract
F-actin, a helical polymer formed by polymerization of the monomers (G-actin), plays crucial roles in various aspects of cell motility. Flexibility of F-actin has been suggested to be important for such a variety of functions. Understanding the flexibility of F-actin requires characterization of a hierarchy of dynamical properties, from internal dynamics of the actin monomers through domain motions within the monomers and relative motions between the monomers within F-actin to large-scale motions of F-actin as a whole. As a first step toward this ultimate purpose, we carried out elastic incoherent neutron scattering experiments on powders of F-actin and G-actin hydrated with D(2)O and characterized the internal dynamics of F-actin and G-actin. Well established techniques and analysis enabled the extraction of mean-square displacements and their temperature dependence in F-actin and in G-actin. An effective force constant analysis with a model consisting of three energy states showed that two dynamical transitions occur at approximately 150 K and approximately 245 K, the former of which corresponds to the onset of anharmonic motions and the latter of which couples with the transition of hydration water. It is shown that behavior of the mean-square displacements is different between G-actin and F-actin, such that G-actin is "softer" than F-actin. The differences in the internal dynamics are detected for the first time between the different structural states (the monomeric state and the polymerized state). The different behavior observed is ascribed to the differences in dynamical heterogeneity between F-actin and G-actin. Based on structural data, the assignment of the differences observed in the two samples to dynamics of specific loop regions involved in the polymerization of G-actin into F-actin is proposed.
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Affiliation(s)
- Satoru Fujiwara
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki 319-1195, Japan.
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46
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Wood K, Grudinin S, Kessler B, Weik M, Johnson M, Kneller GR, Oesterhelt D, Zaccai G. Dynamical heterogeneity of specific amino acids in bacteriorhodopsin. J Mol Biol 2008; 380:581-91. [PMID: 18565346 DOI: 10.1016/j.jmb.2008.04.077] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Accepted: 04/30/2008] [Indexed: 11/28/2022]
Abstract
Components of biological macromolecules, complexes and membranes are animated by motions occurring over a wide range of time and length scales, the synergy of which is at the basis of biological activity. Understanding biological function thus requires a detailed analysis of the underlying dynamical heterogeneity. Neutron scattering, using specific isotope labeling, and molecular dynamics simulations were combined in order to study the dynamics of specific amino acid types in bacteriorhodopsin within the purple membrane (PM) of Halobacterium salinarum. Motions of leucine, isoleucine and tyrosine residues on the pico- to nanosecond time scale were examined separately as a function of temperature from 20 to 300 K. The dynamics of the three residue types displayed different temperature dependence: isoleucine residues have larger displacements compared to the global PM above 120 K; leucine residues have displacements similar to that of PM in the entire temperature range studied; and tyrosine residues have displacements smaller than that of the average membrane in an intermediate temperature range. Experimental features were mostly well reproduced by molecular dynamics simulations performed at five temperatures, which allowed the dynamical characterisation of the amino acids under study as a function of local environment. The resulting dynamical map of bacteriorhodopsin revealed that movements of a specific residue are determined by both its environment and its residue type.
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Affiliation(s)
- K Wood
- Institut Laue-Langevin, 6 rue Jules Horowitz, B.P. 156, 38042 Grenoble Cedex 9, France
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47
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Krishnan M, Kurkal-Siebert V, Smith JC. Methyl Group Dynamics and the Onset of Anharmonicity in Myoglobin. J Phys Chem B 2008; 112:5522-33. [DOI: 10.1021/jp076641z] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Krishnan
- Interdisciplinary Center for Scientific Computing (IWR), University of Heidelberg, Im Neuenheimer Feld 368, D-69120, Heidelberg, Germany, and Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee
| | - V. Kurkal-Siebert
- Interdisciplinary Center for Scientific Computing (IWR), University of Heidelberg, Im Neuenheimer Feld 368, D-69120, Heidelberg, Germany, and Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee
| | - Jeremy C. Smith
- Interdisciplinary Center for Scientific Computing (IWR), University of Heidelberg, Im Neuenheimer Feld 368, D-69120, Heidelberg, Germany, and Center for Molecular Biophysics, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee
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48
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A benchmark for protein dynamics: Ribonuclease A measured by neutron scattering in a large wavevector-energy transfer range. Chem Phys 2008. [DOI: 10.1016/j.chemphys.2007.09.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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49
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Abstract
We used neutron scattering and specific hydrogen-deuterium labeling to investigate the thermal dynamics of isotope-labeled amino acids and retinal, predominantly in the active core and extracellular moiety of bacteriorhodopsin (BR) in the purple membrane and the dynamical response to hydration. Measurements on two neutron spectrometers allowed two populations of motions to be characterized. The lower amplitude motions were found to be the same for both the labeled amino acids and retinal of BR and the global membrane. The larger amplitude dynamics of the labeled part, however, were found to be more resilient than the average membrane, suggesting their functional importance. The response to hydration was characterized, showing that the labeled part of BR is not shielded from hydration effects. The results suggest that the inhibition of high-amplitude motions by lowering hydration may play a key role in the slowing down of the photocycle and the proton pumping activity of BR.
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50
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Wood K, Plazanet M, Gabel F, Kessler B, Oesterhelt D, Zaccai G, Weik M. Dynamics of hydration water in deuterated purple membranes explored by neutron scattering. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:619-26. [PMID: 18286273 PMCID: PMC2755797 DOI: 10.1007/s00249-008-0285-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Revised: 01/22/2008] [Accepted: 01/31/2008] [Indexed: 11/29/2022]
Abstract
The function and dynamics of proteins depend on their direct environment, and much evidence has pointed to a strong coupling between water and protein motions. Recently however, neutron scattering measurements on deuterated and natural-abundance purple membrane (PM), hydrated in H2O and D2O, respectively, revealed that membrane and water motions on the ns-ps time scale are not directly coupled below 260 K (Wood et al. in Proc Natl Acad Sci USA 104:18049-18054, 2007). In the initial study, samples with a high level of hydration were measured. Here, we have measured the dynamics of PM and water separately, at a low-hydration level corresponding to the first layer of hydration water only. As in the case of the higher hydration samples previously studied, the dynamics of PM and water display different temperature dependencies, with a transition in the hydration water at 200 K not triggering a transition in the membrane at the same temperature. Furthermore, neutron diffraction experiments were carried out to monitor the lamellar spacing of a flash-cooled deuterated PM stack hydrated in H2O as a function of temperature. At 200 K, a sudden decrease in lamellar spacing indicated the onset of long-range translational water diffusion in the second hydration layer as has already been observed on flash-cooled natural-abundance PM stacks hydrated in D2O (Weik et al. in J Mol Biol 275:632-634, 2005), excluding thus a notable isotope effect. Our results reinforce the notion that membrane-protein dynamics may be less strongly coupled to hydration water motions than the dynamics of soluble proteins.
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Affiliation(s)
- K Wood
- Laboratoire de Biophysique Moléculaire, Institut de Biologie Structurale CEA-CNRS-UJF, 41 rue Jules Horowitz, 38027 Grenoble Cedex 1, France
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