1
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Omwansu W, Musembi R, Derese S. Graph-based analysis of H-bond networks and unsupervised learning reveal conformational coupling in prion peptide segments. Phys Chem Chem Phys 2024. [PMID: 39291469 DOI: 10.1039/d4cp02123a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
In this study, we employed a comprehensive computational approach to investigate the physical chemistry of the water networks surrounding hydrated peptide segments, as derived from molecular dynamics simulations. Our analysis uncovers a complex interplay of direct and water-mediated hydrogen bonds that intricately weave through the peptides. We demonstrate that these hydrogen bond networks encode critical information about the peptides' conformational behavior, with the dimensionality of these networks showing sensitivity to the peptides' conformations. Additionally, we estimated the free-energy landscape of the peptides across various conformations, revealing that their structures are predominantly characterized by unfolded, partially folded, and folded configurations, resulting in broad and rugged free-energy surfaces due to the numerous degrees of freedom contributed by the surrounding solvent. Importantly, the structured nature of this free-energy landscape becomes obscured when conventional collective variables, such as the number of hydrogen bonds, are used. Our findings provide new insights into the molecular mechanisms that couple protein and solvent degrees of freedom, highlighting their significance in the functioning of biological systems.
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Affiliation(s)
- Wycliffe Omwansu
- Department of Physics, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.
- The Abdus Salam International Centre for Theoretical Physics, Strada Costiera 11, 34151 Trieste, Italy
| | - Robinson Musembi
- Department of Physics, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya.
| | - Solomon Derese
- Department of Chemistry, University of Nairobi, P.O. Box 30197-00100, Nairobi, Kenya
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2
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Cropley TC, Liu FC, Chai M, Bush MF, Bleiholder C. Metastability of Protein Solution Structures in the Absence of a Solvent: Rugged Energy Landscape and Glass-like Behavior. J Am Chem Soc 2024:10.1021/jacs.3c12892. [PMID: 38598661 PMCID: PMC11464637 DOI: 10.1021/jacs.3c12892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Native ion mobility/mass spectrometry is well-poised to structurally screen proteomes but characterizes protein structures in the absence of a solvent. This raises long-standing unanswered questions about the biological significance of protein structures identified through ion mobility/mass spectrometry. Using newly developed computational and experimental ion mobility/ion mobility/mass spectrometry methods, we investigate the unfolding of the protein ubiquitin in a solvent-free environment. Our data suggest that the folded, solvent-free ubiquitin observed by ion mobility/mass spectrometry exists in a largely native fold with an intact β-grasp motif and α-helix. The ensemble of folded, solvent-free ubiquitin ions can be partitioned into kinetically stable subpopulations that appear to correspond to the structural heterogeneity of ubiquitin in solution. Time-resolved ion mobility/ion mobility/mass spectrometry measurements show that folded, solvent-free ubiquitin exhibits a strongly stretched-exponential time dependence, which simulations trace to a rugged energy landscape with kinetic traps. Unfolding rate constants are estimated to be approximately 800 to 20,000 times smaller than in the presence of water, effectively quenching the unfolding process on the time scale of typical ion mobility/mass spectrometry measurements. Our proposed unfolding pathway of solvent-free ubiquitin shares substantial characteristics with that established for the presence of solvent, including a polarized transition state with significant native content in the N-terminal β-hairpin and α-helix. Our experimental and computational data suggest that (1) the energy landscape governing the motions of folded, solvent-free proteins is rugged in analogy to that of glassy systems; (2) large-scale protein motions may at least partially be determined by the amino acid sequence of a polypeptide chain; and (3) solvent facilitates, rather than controls, protein motions.
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Affiliation(s)
- Tyler. C. Cropley
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32304, USA
| | - Fanny. C. Liu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32304, USA
| | - Mengqi Chai
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32304, USA
| | - Matthew F. Bush
- Department of Chemistry, University of Washington, Box 351700, Seattle, WA 98195-1700
| | - Christian Bleiholder
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32304, USA
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32304, USA
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3
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Chen M, Kálai T, Cascio D, Bridges MD, Whitelegge JP, Elgeti M, Hubbell WL. A Highly Ordered Nitroxide Side Chain for Distance Mapping and Monitoring Slow Structural Fluctuations in Proteins. APPLIED MAGNETIC RESONANCE 2023; 55:251-277. [PMID: 38357006 PMCID: PMC10861403 DOI: 10.1007/s00723-023-01618-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 09/06/2023] [Accepted: 09/09/2023] [Indexed: 02/16/2024]
Abstract
Site-directed spin labeling electron paramagnetic resonance (SDSL-EPR) is an established tool for exploring protein structure and dynamics. Although nitroxide side chains attached to a single cysteine via a disulfide linkage are commonly employed in SDSL-EPR, their internal flexibility complicates applications to monitor slow internal motions in proteins and to structure determination by distance mapping. Moreover, the labile disulfide linkage prohibits the use of reducing agents often needed for protein stability. To enable the application of SDSL-EPR to the measurement of slow internal dynamics, new spin labels with hindered internal motion are desired. Here, we introduce a highly ordered nitroxide side chain, designated R9, attached at a single cysteine residue via a non-reducible thioether linkage. The reaction to introduce R9 is highly selective for solvent-exposed cysteine residues. Structures of R9 at two helical sites in T4 Lysozyme were determined by X-ray crystallography and the mobility in helical sequences was characterized by EPR spectral lineshape analysis, Saturation Transfer EPR, and Saturation Recovery EPR. In addition, interspin distance measurements between pairs of R9 residues are reported. Collectively, all data indicate that R9 will be useful for monitoring slow internal structural fluctuations, and applications to distance mapping via dipolar spectroscopy and relaxation enhancement methods are anticipated. Supplementary Information The online version contains supplementary material available at 10.1007/s00723-023-01618-8.
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Affiliation(s)
- Mengzhen Chen
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095 USA
| | - Tamás Kálai
- Institute of Organic and Medicinal Chemistry, Faculty of Pharmacy, University of Pécs, Szigeti St. 12, Pecs, 7624 Hungary
| | - Duilio Cascio
- Department of Biological Chemistry, UCLA-DOE Institute, Howard Hughes Medical Institute, and Molecular Biology Institute, University of California, Los Angeles, CA 90095 USA
| | - Michael D. Bridges
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095 USA
| | - Julian P. Whitelegge
- The Pasarow Mass Spectrometry Laboratory, David Geffen School of Medicine, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA 90095 USA
| | - Matthias Elgeti
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095 USA
- Present Address: Institute for Drug Discovery, Leipzig University Medical Center, Härtelstr. 16-18, 04107 Leipzig, Germany
| | - Wayne L. Hubbell
- Jules Stein Eye Institute and Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095 USA
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4
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Nag R, Joshi S, Rathore AS, Majumder S. Profiling Enzyme Activity of l-Asparaginase II by NMR-Based Methyl Fingerprinting at Natural Abundance. J Am Chem Soc 2023; 145:10826-10838. [PMID: 37154467 DOI: 10.1021/jacs.3c02154] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
l-asparaginase II (MW 135 kDa) from E. coli is an FDA-approved protein drug used for the treatment of childhood leukemia. Despite its long history as a chemotherapeutic, the structural basis of enzyme action, in solution, remains widely contested. In this work, methyl-based 2D [1H-13C]-heteronuclear single-quantum correlation (HSQC) NMR, at natural abundance, has been used to profile the enzymatic activity of the commercially available enzyme drug. The [1H-13C]-HSQC NMR spectra of the protein reveal the role of a flexible loop segment in the activity of the enzyme, in solution. Addition of asparagine to the protein results in distinct conformational changes of the loop that could be signatures of intermediates formed in the catalytic reaction. To this end, an isothermal titration calorimetry (ITC)-based assay has been developed to measure the enzymatic reaction enthalpy, as a marker for its activity. Combining both ITC and NMR, it was shown that the disruption of the protein conformation can result in the loss of function. The scope, robustness, and validity of the loop fingerprints in relation to enzyme activity have been tested under different solution conditions. Overall, our results indicate that 2D NMR can be used reliably to gauge the structure-function of this enzyme, bypassing the need to label the protein. Such natural abundant NMR methods can be potentially extended to probe the structure-function aspects of high-molecular-weight protein therapeutics (glycosylated protein drugs, enzymes, therapeutic monoclonal antibodies, antibody-drug conjugates, and Fc-fusion proteins), where (a) flexible loops are required for their function and (b) isotope labeling may not be straightforward.
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Affiliation(s)
- Rachayita Nag
- Biophysics & Structural Genomics, Saha Institute of Nuclear Physics, Kolkata 700064, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
| | - Srishti Joshi
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Anurag Singh Rathore
- Department of Chemical Engineering, Indian Institute of Technology, Hauz Khas, New Delhi 110016, India
| | - Subhabrata Majumder
- Biophysics & Structural Genomics, Saha Institute of Nuclear Physics, Kolkata 700064, India
- Homi Bhabha National Institute, Anushaktinagar, Mumbai 400094, India
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5
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Stachowski TR, Vanarotti M, Seetharaman J, Lopez K, Fischer M. Water Networks Repopulate Protein-Ligand Interfaces with Temperature. Angew Chem Int Ed Engl 2022; 61:e202112919. [PMID: 35648650 PMCID: PMC9329195 DOI: 10.1002/anie.202112919] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Indexed: 12/14/2022]
Abstract
High-resolution crystal structures highlight the importance of water networks in protein-ligand interactions. However, as these are typically determined at cryogenic temperature, resulting insights may be structurally precise but not biologically accurate. By collecting 10 matched room-temperature and cryogenic datasets of the biomedical target Hsp90α, we identified changes in water networks that impact protein conformations at the ligand binding interface. Water repositioning with temperature repopulates protein ensembles and ligand interactions. We introduce Flipper conformational barcodes to identify temperature-sensitive regions in electron density maps. This revealed that temperature-responsive states coincide with ligand-responsive regions and capture unique binding signatures that disappear upon cryo-cooling. Our results have implications for discovering Hsp90 selective ligands, and, more generally, for the utility of hidden protein and water conformations in drug discovery.
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Affiliation(s)
- Timothy R. Stachowski
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Murugendra Vanarotti
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Jayaraman Seetharaman
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTN 38105USA
| | - Karlo Lopez
- School of Natural SciencesMathematicsand EngineeringCalifornia State UniversityBakersfieldCA 93311USA
| | - Marcus Fischer
- Department of Chemical Biology & TherapeuticsSt. Jude Children's Research HospitalMemphisTN 38105USA
- Department of Structural BiologySt. Jude Children's Research HospitalMemphisTN 38105USA
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6
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Doan LC, Dahanayake JN, Mitchell-Koch KR, Singh AK, Vinh NQ. Probing Adaptation of Hydration and Protein Dynamics to Temperature. ACS OMEGA 2022; 7:22020-22031. [PMID: 35785325 PMCID: PMC9245114 DOI: 10.1021/acsomega.2c02843] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Protein dynamics is strongly influenced by the surrounding environment and physiological conditions. Here we employ broadband megahertz-to-terahertz spectroscopy to explore the dynamics of water and myoglobin protein on an extended time scale from femto- to nanosecond. The dielectric spectra reveal several relaxations corresponding to the orientational polarization mechanism, including the dynamics of loosely bound, tightly bound, and bulk water, as well as collective vibrational modes of protein in an aqueous environment. The dynamics of loosely bound and bulk water follow non-Arrhenius behavior; however, the dynamics of water molecules in the tightly bound layer obeys the Arrhenius-type relation. Combining molecular simulations and effective-medium approximation, we have determined the number of water molecules in the tightly bound hydration layer and studied the dynamics of protein as a function of temperature. The results provide the important impact of water on the biochemical functions of proteins.
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Affiliation(s)
- Luan C. Doan
- Department
of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department
of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Jayangika N. Dahanayake
- Department
of Chemistry, Faculty of Science, University
of Kelaniya, Kelaniya 11600, Sri Lanka
| | | | - Abhishek K. Singh
- Department
of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia 24061, United States
| | - Nguyen Q. Vinh
- Department
of Physics and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, Virginia 24061, United States
- Department
of Mechanical Engineering, Virginia Tech, Blacksburg, Virginia 24061, United States
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7
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Stachowski TR, Vanarotti M, Seetharaman J, Lopez K, Fischer M. Water Networks Repopulate Protein‐Ligand Interfaces With Temperature. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202112919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Timothy R Stachowski
- St Jude Children's Research Hospital Chemical Biology & Therapeutics UNITED STATES
| | - Murugendra Vanarotti
- St Jude Children's Research Hospital Chemical Biology & Therapeutics UNITED STATES
| | | | - Karlo Lopez
- California State University - Bakersfield School of Natural Sciences, Mathematics, and Engineering UNITED STATES
| | - Marcus Fischer
- St. Jude Children's Research Hospital Chemical Biology & Therapeutics 262 Danny Thomas Place 38105 Memphis UNITED STATES
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8
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Hung CL, Kuo YH, Lee SW, Chiang YW. Protein Stability Depends Critically on the Surface Hydrogen-Bonding Network: A Case Study of Bid Protein. J Phys Chem B 2021; 125:8373-8382. [PMID: 34314184 DOI: 10.1021/acs.jpcb.1c03245] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding how proteins retain structural stability is not only of fundamental importance in biophysics but also critical to industrial production of antibodies and vaccines. Protein stability is known to depend mainly on two effects: internal hydrophobicity and H-bonding between the protein surface and solvent. A challenging task is to identify their individual contributions to a protein. Here, we investigate the structural stability of the apoptotic Bid protein in solutions containing various concentrations of guanidinium hydrochloride and urea using a combination of recently developed methods including the QTY (glutamine, threonine, and tyrosine) code and electron spin resonance-based peak-height analysis. We show that when the internal hydrophobicity of Bid is broken down using the QTY code, the surface H-bonding alone is sufficient to retain the structural stability intact. When the surface H-bonding is disrupted, Bid becomes sensitive to the temperature-dependent internal hydrophobicity such that it exhibits a reversible cold unfolding above water's freezing point. Using the combined approach, we show that the free-energy contributions of the two effects can be more reliably obtained. The surface H bonds are more important than the other effect in determining the structural stability of Bid protein.
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Affiliation(s)
- Chien-Lun Hung
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yun-Hsuan Kuo
- Department of Chemistry, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan
| | - Su Wei Lee
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu 30013, Taiwan
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9
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Soetbeer J, Millen M, Zouboulis K, Hülsmann M, Godt A, Polyhach Y, Jeschke G. Dynamical decoupling in water-glycerol glasses: a comparison of nitroxides, trityl radicals and gadolinium complexes. Phys Chem Chem Phys 2021; 23:5352-5369. [PMID: 33635938 DOI: 10.1039/d1cp00055a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our previous study on nitroxides in o-terphenyl (OTP) revealed two separable decoherence processes at low temperatures, best captured by the sum of two stretched exponentials (SSE) model. Dynamical decoupling (DD) extends both associated dephasing times linearly for 1 to 5 refocusing pulses [Soetbeer et al., Phys. Chem. Chem. Phys., 2018, 20, 1615]. Here we demonstrate an analogous DD behavior of water-soluble nitroxides in water-glycerol glass by using nitroxide and/or solvent deuteration for component assignment. Compared to the conventional Hahn experiment, we show that Carr-Purcell and Uhrig DD schemes are superior in resolving and identifying active dephasing mechanisms. Thereby, we observe a partial coherence loss to intramolecular nitroxide and trityl nuclei that can be alleviated, while the zero field splitting-induced losses for gadolinium labels cannot be refocused and contribute even at the central transition of this spin-7/2 system. Independent of the studied spin system, Uhrig DD leads to a characteristic convex dephasing envelope in both protonated water-glycerol and OTP glass, thus outperforming the Carr-Purcell scheme.
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Affiliation(s)
- Janne Soetbeer
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland.
| | - Marthe Millen
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland.
| | - Konstantin Zouboulis
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland.
| | - Miriam Hülsmann
- Bielefeld University, Department of Chemistry, Universitätsstr. 25, D-33615 Bielefeld, Germany
| | - Adelheid Godt
- Bielefeld University, Department of Chemistry, Universitätsstr. 25, D-33615 Bielefeld, Germany
| | - Yevhen Polyhach
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland.
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland.
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10
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Lan YJ, Yeh PS, Kao TY, Lo YC, Sue SC, Chen YW, Hwang DW, Chiang YW. Anti-apoptotic BCL-2 regulation by changes in dynamics of its long unstructured loop. Commun Biol 2020; 3:668. [PMID: 33184407 PMCID: PMC7665024 DOI: 10.1038/s42003-020-01390-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022] Open
Abstract
BCL-2, a key protein in inhibiting apoptosis, has a 65-residue-long highly flexible loop domain (FLD) located on the opposite side of its ligand-binding groove. In vivo phosphorylation of the FLD enhances the affinity of BCL-2 for pro-apoptotic ligands, and consequently anti-apoptotic activity. However, it remains unknown as to how the faraway, unstructured FLD modulates the affinity. Here we investigate the protein-ligand interactions by fluorescence techniques and monitor protein dynamics by DEER and NMR spectroscopy tools. We show that phosphomimetic mutations on the FLD lead to a reduction in structural flexibility, hence promoting ligand access to the groove. The bound pro-apoptotic ligands can be displaced by the BCL-2-selective inhibitor ABT-199 efficiently, and thus released to trigger apoptosis. We show that changes in structural flexibility on an unstructured loop can activate an allosteric protein that is otherwise structurally inactive.
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Affiliation(s)
- Yu-Jing Lan
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Pei-Shan Yeh
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Te-Yu Kao
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Yuan-Chao Lo
- Biomedical Translation Research Center, Academia Sinica, Taipei, Taiwan
| | - Shih-Che Sue
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Yu-Wen Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Dennis W Hwang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
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11
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Pospíšil P, Sýkora J, Takematsu K, Hof M, Gray HB, Vlček A. Light-Induced Nanosecond Relaxation Dynamics of Rhenium-Labeled Pseudomonas aeruginosa Azurins. J Phys Chem B 2020; 124:788-797. [PMID: 31935093 DOI: 10.1021/acs.jpcb.9b10802] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Time-resolved phosphorescence spectra of Re(CO)3(dmp)+ and Re(CO)3(phen)+ chromophores (dmp = 4,7-dimethyl-1,10-phenanthroline, phen = 1,10-phenanthroline) bound to surface histidines (H83, H124, and H126) of Pseudomonas aeruginosa azurin mutants exhibit dynamic band maxima shifts to lower wavenumbers following 3-exponential kinetics with 1-5 and 20-100 ns major phases and a 1.1-2.5 μs minor (5-16%) phase. Observation of slow relaxation components was made possible by using an organometallic Re chromophore as a probe whose long phosphorescence lifetime extends the observation window up to ∼3 μs. Integrated emission-band areas also decay with 2- or 3-exponential kinetics; the faster decay phase(s) is relaxation-related, whereas the slowest one [360-680 ns (dmp); 90-140 ns (phen)] arises mainly from population decay. As a result of shifting bands, the emission intensity decay kinetics depend on the detection wavelength. Detailed kinetics analyses and comparisons with band-shift dynamics are needed to disentangle relaxation and population decay kinetics if they occur on comparable timescales. The dynamic phosphorescence Stokes shift in Re-azurins is caused by relaxation motions of the solvent, the protein, and solvated amino acid side chains at the Re binding site in response to chromophore electronic excitation. Comparing relaxation and decay kinetics of Re(dmp)124K122CuII and Re(dmp)124W122CuII suggests that electron transfer (ET) and relaxation motions in the W122 mutant are coupled. It follows that nanosecond and faster photo-induced ET steps in azurins (and likely other redox proteins) occur from unrelaxed systems; importantly, these reactions can be driven (or hindered) by structural and solvational dynamics.
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Affiliation(s)
- Petr Pospíšil
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic
| | - Jan Sýkora
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic
| | - Kana Takematsu
- Department of Chemistry , Bowdoin College , Brunswick , Maine 04011 , United States
| | - Martin Hof
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic
| | - Harry B Gray
- Beckman Institute , California Institute of Technology , Pasadena , California 91125 , United States
| | - Antonín Vlček
- J. Heyrovský Institute of Physical Chemistry , Czech Academy of Sciences , Dolejškova 3 , CZ-182 23 Prague , Czech Republic.,School of Biological and Chemical Sciences , Queen Mary University of London , Mile End Road , E1 4NS London , U.K
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12
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Pinzan F, Artzner F, Ghoufi A. Anomalous dynamics of water at the octopeptide lanreotide surface. RSC Adv 2020; 10:33903-33910. [PMID: 35519054 PMCID: PMC9056749 DOI: 10.1039/d0ra06237e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 08/25/2020] [Indexed: 11/21/2022] Open
Abstract
This work reports the study of water dynamics close to the cyclic octapeptide lanreotide from atomistic simulations of hydrated lanreotide, a cyclic octapeptide. Calculation of the hydrogen bonds between water molecules allows mapping of the hydrophilic regions of lanreotide. Whereas a super-diffusivity of the interfacial water molecules is established, a slowdown in rotational dynamics is observed, involving a decoupling between both processes. Acceleration in translation dynamics is connected to the hopping process between hydrophilic zones. Microscopically, this is correlated with the weakness of the interfacial hydrogen bonding network due to a hydrophobic interface at the origin of the interfacial sliding of water molecules. Heterogeneous rotational dynamics of water molecules close the lanreotide surface is evidenced and connected to heterogeneous hydration. Molecular dynamics simulations of a hydrated mutated lanreotide, a cyclic octapeptide, were carried out to characterize its hydration state. We studied the water dynamics close to the peptide using atomistic simulations.![]()
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Affiliation(s)
- Florian Pinzan
- Institut de Physique de Rennes
- UMR CNRS 6251
- Université Rennes 1
- 35042 Rennes
- France
| | - Franck Artzner
- Institut de Physique de Rennes
- UMR CNRS 6251
- Université Rennes 1
- 35042 Rennes
- France
| | - Aziz Ghoufi
- Institut de Physique de Rennes
- UMR CNRS 6251
- Université Rennes 1
- 35042 Rennes
- France
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13
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Schirò G, Weik M. Role of hydration water in the onset of protein structural dynamics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:463002. [PMID: 31382251 DOI: 10.1088/1361-648x/ab388a] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Proteins are the molecular workhorses in a living organism. Their 3D structures are animated by a multitude of equilibrium fluctuations and specific out-of-equilibrium motions that are required for proteins to be biologically active. When studied as a function of temperature, functionally relevant dynamics are observed at and above the so-called protein dynamical transition (~240 K) in hydrated, but not in dry proteins. In this review we present and discuss the main experimental and computational results that provided evidence for the dynamical transition, with a focus on the role of hydration water dynamics in sustaining functional protein dynamics. The coupling and mutual influence of hydration water dynamics and protein dynamics are discussed and the hypotheses illustrated that have been put forward to explain the physical origin of their onsets.
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Affiliation(s)
- Giorgio Schirò
- Institut de Biologie Structurale, Université Grenoble Alpes, CNRS, CEA, Grenoble, France
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14
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de Miguel R, Rubí JM. Negative Thermophoretic Force in the Strong Coupling Regime. PHYSICAL REVIEW LETTERS 2019; 123:200602. [PMID: 31809117 DOI: 10.1103/physrevlett.123.200602] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Indexed: 06/10/2023]
Abstract
Negative thermophoresis (a particle moving up the temperature gradient) is a somewhat counterintuitive phenomenon which has thus far eluded a simple thermostatistical description. The purpose of this Letter is to show that a thermodynamic framework based on the formulation of a Hamiltonian of mean force has the descriptive ability to capture this interesting and elusive phenomenon in an unusually elegant and straightforward fashion. We propose a mechanism that describes the advent of a thermophoretic force acting from cold to hot on systems that are strongly coupled to a nonisothermal heat bath. When a system is strongly coupled to the heat bath, the system's eigenenergies E_{j} become effectively temperature dependent. This adjustment of the energy levels allows the system to take heat from the environment, +d⟨E_{j}⟩, and return it as work, -d⟨TdE_{j}/dT⟩. This effect can make the temperature dependence of the effective energy profile nonmonotonic. As a result, particles may experience a force in either direction depending on the temperature.
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Affiliation(s)
- Rodrigo de Miguel
- Department of Teacher Education, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
| | - J Miguel Rubí
- Department of Condensed Matter Physics, University of Barcelona, E-08028 Barcelona, Spain
- PoreLab-Center of Excellence, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
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Lai Y, Kuo Y, Chiang Y. Identifying Protein Conformational Dynamics Using Spin‐label ESR. Chem Asian J 2019; 14:3981-3991. [DOI: 10.1002/asia.201900855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/02/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Yei‐Chen Lai
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
- Department of Chemistry&Biochemistry University of California Santa Barbara CA 93106-9510 USA
| | - Yun‐Hsuan Kuo
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
| | - Yun‐Wei Chiang
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
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