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Laurent H, Hughes MDG, Walko M, Brockwell DJ, Mahmoudi N, Youngs TGA, Headen TF, Dougan L. Visualization of Self-Assembly and Hydration of a β-Hairpin through Integrated Small and Wide-Angle Neutron Scattering. Biomacromolecules 2023; 24:4869-4879. [PMID: 37874935 PMCID: PMC10646990 DOI: 10.1021/acs.biomac.3c00583] [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] [Received: 06/14/2023] [Revised: 10/03/2023] [Indexed: 10/26/2023]
Abstract
Fundamental understanding of the structure and assembly of nanoscale building blocks is crucial for the development of novel biomaterials with defined architectures and function. However, accessing self-consistent structural information across multiple length scales is challenging. This limits opportunities to exploit atomic scale interactions to achieve emergent macroscale properties. In this work we present an integrative small- and wide-angle neutron scattering approach coupled with computational modeling to reveal the multiscale structure of hierarchically self-assembled β hairpins in aqueous solution across 4 orders of magnitude in length scale from 0.1 Å to 300 nm. Our results demonstrate the power of this self-consistent cross-length scale approach and allows us to model both the large-scale self-assembly and small-scale hairpin hydration of the model β hairpin CLN025. Using this combination of techniques, we map the hydrophobic/hydrophilic character of this model self-assembled biomolecular surface with atomic resolution. These results have important implications for the multiscale investigation of aqueous peptides and proteins, for the prediction of ligand binding and molecular associations for drug design, and for understanding the self-assembly of peptides and proteins for functional biomaterials.
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Affiliation(s)
- Harrison Laurent
- School
of Physics and Astronomy, University of
Leeds, Leeds, United Kingdom, LS2
9JT
| | - Matt D. G. Hughes
- School
of Physics and Astronomy, University of
Leeds, Leeds, United Kingdom, LS2
9JT
- Astbury
Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom LS2
9JT
| | - Martin Walko
- School
of Chemistry, University of Leeds, Leeds, United
Kingdom, LS2 9JT
| | - David J. Brockwell
- Astbury
Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom LS2
9JT
| | - Najet Mahmoudi
- ISIS
Neutron and Muon Source, Rutherford Appleton
Laboratory, Harwell Oxford, Didcot, United Kingdom, OX11 0QX
| | - Tristan G. A. Youngs
- ISIS
Neutron and Muon Source, Rutherford Appleton
Laboratory, Harwell Oxford, Didcot, United Kingdom, OX11 0QX
| | - Thomas F. Headen
- ISIS
Neutron and Muon Source, Rutherford Appleton
Laboratory, Harwell Oxford, Didcot, United Kingdom, OX11 0QX
| | - Lorna Dougan
- School
of Physics and Astronomy, University of
Leeds, Leeds, United Kingdom, LS2
9JT
- Astbury
Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom LS2
9JT
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2
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Laurent H, Youngs TGA, Headen TF, Soper AK, Dougan L. The ability of trimethylamine N-oxide to resist pressure induced perturbations to water structure. Commun Chem 2022; 5:116. [PMID: 36697784 PMCID: PMC9814673 DOI: 10.1038/s42004-022-00726-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 08/19/2022] [Indexed: 01/28/2023] Open
Abstract
Trimethylamine N-oxide (TMAO) protects organisms from the damaging effects of high pressure. At the molecular level both TMAO and pressure perturb water structure but it is not understood how they act in combination. Here, we use neutron scattering coupled with computational modelling to provide atomistic insight into the structure of water under pressure at 4 kbar in the presence and absence of TMAO. The data reveal that TMAO resists pressure-induced perturbation to water structure, particularly in retaining a clear second solvation shell, enhanced hydrogen bonding between water molecules and strong TMAO - water hydrogen bonds. We calculate an 'osmolyte protection' ratio at which pressure and TMAO-induced energy changes effectively cancel out. Remarkably this ratio translates across scales to the organism level, matching the observed concentration dependence of TMAO in the muscle tissue of organisms as a function of depth. Osmolyte protection may therefore offer a molecular mechanism for the macroscale survival of life in extreme environments.
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Affiliation(s)
- Harrison Laurent
- grid.9909.90000 0004 1936 8403School of Physics and Astronomy, University of Leeds, Leeds, UK
| | - Tristan G. A. Youngs
- grid.76978.370000 0001 2296 6998ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot, UK
| | - Thomas F. Headen
- grid.76978.370000 0001 2296 6998ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot, UK
| | - Alan K. Soper
- grid.76978.370000 0001 2296 6998ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot, UK
| | - Lorna Dougan
- grid.9909.90000 0004 1936 8403School of Physics and Astronomy, University of Leeds, Leeds, UK ,grid.9909.90000 0004 1936 8403Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds, UK
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Fetahaj Z, Jaworek MW, Oliva R, Winter R. Suppression of Liquid‐Liquid Phase Separation and Aggregation of Antibodies by Modest Pressure Application. Chemistry 2022; 28:e202201658. [PMID: 35759377 PMCID: PMC9544093 DOI: 10.1002/chem.202201658] [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: 05/30/2022] [Indexed: 11/09/2022]
Abstract
The high colloidal stability of antibody (immunoglobulin) solutions is important for pharmaceutical applications. Inert cosolutes, excipients, are generally used in therapeutic protein formulations to minimize physical instabilities, such as liquid–liquid phase separation (LLPS), aggregation and precipitation, which are often encountered during manufacturing and storage. Despite their widespread use, a detailed understanding of how excipients modulate the specific protein‐protein interactions responsible for these instabilities is still lacking. In this work, we demonstrate the high sensitivity to pressure of globulin condensates as a suitable means to suppress LLPS and subsequent aggregation of concentrated antibody solutions. The addition of excipients has only a minor effect. The high pressure sensitivity observed is due to the fact that these flexible Y‐shaped molecules create a considerable amount of void volume in the condensed phase, leading to an overall decrease in the volume of the system upon dissociation of the droplet phase by pressure already at a few tens of to hundred bar. Moreover, we show that immunoglobulin molecules themselves are highly resistant to unfolding under pressure, and can even sustain pressures up to about 6 kbar without conformational changes. This implies that immunoglobulins are resistant to the pressure treatment of foods, such as milk, in high‐pressure food‐processing technologies, thereby preserving their immunological activity.
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Affiliation(s)
- Zamira Fetahaj
- Physical Chemistry I–Biophysical Chemistry Department of Chemistry and Chemical Biology TU Dortmund Otto-Hahn-Strasse 4a 44227 Dortmund Germany
| | - Michel W. Jaworek
- Physical Chemistry I–Biophysical Chemistry Department of Chemistry and Chemical Biology TU Dortmund Otto-Hahn-Strasse 4a 44227 Dortmund Germany
| | - Rosario Oliva
- Physical Chemistry I–Biophysical Chemistry Department of Chemistry and Chemical Biology TU Dortmund Otto-Hahn-Strasse 4a 44227 Dortmund Germany
- Department of Chemical Sciences University of Naples Federico II Via Cintia 4 80126 Naples Italy
| | - Roland Winter
- Physical Chemistry I–Biophysical Chemistry Department of Chemistry and Chemical Biology TU Dortmund Otto-Hahn-Strasse 4a 44227 Dortmund Germany
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Baksi A, Biswas R. Dynamical Anomaly of Aqueous Amphiphilic Solutions: Connection to Solution H-Bond Fluctuation Dynamics? ACS OMEGA 2022; 7:10970-10984. [PMID: 35415359 PMCID: PMC8991915 DOI: 10.1021/acsomega.1c06831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
We have investigated the possible connection between "dynamical anomaly" observed in time-resolved fluorescence measurements of reactive and nonreactive solute-centered relaxation dynamics in aqueous binary mixtures of different amphiphiles and the solution intra- and interspecies H-bond fluctuation dynamics. Earlier studies have connected the anomalous thermodynamic properties of binary mixtures at very low amphiphile concentrations to the structural distortion of water. This is termed as "structural anomaly." Interestingly, the abrupt changes in the composition-dependent average rates of solute relaxation dynamics occur at amphiphile mole fractions approximately twice as large as those where structural anomalies appear. We have investigated this anomalous solution dynamical aspect by considering (water + tertiary butanol) as a model system and performed molecular dynamics simulations at several tertiary butanol (TBA) concentrations covering the extremely dilute to the moderately concentrated regimes. The "dynamical anomaly" has been followed via monitoring the composition dependence of the intra- and interspecies H-bond fluctuations and reorientational relaxations of TBA and water molecules. Solution structural aspects have been followed via examining the tetrahedral order parameter, radial and spatial distribution functions, numbers of H bonds per water and TBA molecules, and the respective populations participating in H-bond formation. Our simulations reveal abrupt changes in the H-bond fluctuations and reorientational dynamics and tetrahedral order parameter at amphiphile concentrations differing approximately by a factor of 2 and corroborates well with the steady-state and the time-resolved spectroscopic measurements. This work therefore explains, following a uniform and cogent manner, both the experimentally observed structural and dynamical anomalies in microscopic terms.
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Cinar H, Oliva R, Wu H, Zhang M, Chan HS, Winter R. Effects of Cosolvents and Crowding Agents on the Stability and Phase Transition Kinetics of the SynGAP/PSD-95 Condensate Model of Postsynaptic Densities. J Phys Chem B 2022; 126:1734-1741. [PMID: 35171623 DOI: 10.1021/acs.jpcb.2c00794] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The SynGAP/PSD-95 binary protein system serves as a simple mimicry of postsynaptic densities (PSDs), which are protein assemblies based largely on liquid-liquid phase separation (LLPS), that are located underneath the plasma membrane of excitatory synapses. Surprisingly, the LLPS of the SynGAP/PSD-95 system is much more pressure sensitive than typical folded states of proteins or nucleic acids. It was found that phase-separated SynGAP/PSD-95 droplets dissolve into a homogeneous solution at a pressure of tens to hundred bar. Since organisms in the deep sea are exposed to pressures of up to ∼1000 bar, this observation suggests that deep-sea organisms must counteract the high pressure sensitivity of PSDs to avoid neurological impairment. We demonstrate here that the compatible osmolyte trimethylamine-N-oxide (TMAO) as well as macromolecular crowding agents at moderate concentrations can mitigate the deleterious effect of pressure on SynGAP/PSD-95 droplet stability, extending stable LLPS up to almost a kbar level. Moreover, the formation of SynGAP/PSD-95 droplets is a very rapid process that can be switched on and off in seconds. In contrast with the marked effects of the cosolutes on droplet stability, at the cosolutes' respective biologically relevant concentrations, their impact on the phase transformation kinetics is rather small. Only a high TMAO concentration results in a significant kinetic retardation of LLPS. Taken together, these findings offer new biophysical insights into the neurological effects of hydrostatic pressure. In particular, our results indicate how pressure-induced neurological disorders might be alleviated by upregulating certain cosolutes in the cellular milieu.
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Affiliation(s)
- Hasan Cinar
- Physical Chemistry I - Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Rosario Oliva
- Physical Chemistry I - Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
| | - Haowei Wu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China.,School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Hue Sun Chan
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Roland Winter
- Physical Chemistry I - Biophysical Chemistry, Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 4a, 44227 Dortmund, Germany
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6
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Laurent H, Baker DL, Soper AK, Ries ME, Dougan L. Bridging Structure, Dynamics, and Thermodynamics: An Example Study on Aqueous Potassium Halides. J Phys Chem B 2021; 125:12774-12786. [PMID: 34757756 DOI: 10.1021/acs.jpcb.1c06728] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aqueous salt systems are ubiquitous in all areas of life. The ions in these solutions impose important structural and dynamic perturbations to water. In this study, we employ a combined neutron scattering, nuclear magnetic resonance, and computational modeling approach to deconstruct ion-specific perturbations to water structure and dynamics and shed light on the molecular origins of bulk thermodynamic properties of the solutions. Our approach uses the atomistic scale resolution offered to us by neutron scattering and computational modeling to investigate how the properties of particular short-ranged microenvironments within aqueous systems can be related to bulk properties of the system. We find that by considering only the water molecules in the first hydration shell of the ions that the enthalpy of hydration can be determined. We also quantify the range over which ions perturb water structure by calculating the average enthalpic interaction between a central halide anion and the surrounding water molecules as a function of distance and find that the favorable anion-water enthalpic interactions only extend to ∼4 Å. We further validate this by showing that ions induce structure in their solvating water molecules by examining the distribution of dipole angles in the first hydration shell of the ions but that this perturbation does not extend into the bulk water. We then use these structural findings to justify mathematical models that allow us to examine perturbations to rotational and diffusive dynamics in the first hydration shell around the potassium halide ions from NMR measurements. This shows that as one moves down the halide series from fluorine to iodine, and ionic charge density is therefore reduced, that the enthalpy of hydration becomes less negative. The first hydration shell also becomes less well structured, and rotational and diffusive motions of the hydrating water molecules are increased. This reduction in structure and increase in dynamics are likely the origin of the previously observed increased entropy of hydration as one moves down the halide series. These results also suggest that simple monovalent potassium halide ions induce mostly local perturbations to water structure and dynamics.
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Affiliation(s)
- Harrison Laurent
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Daniel L Baker
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Alan K Soper
- ISIS Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, U.K
| | - Michael E Ries
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K
| | - Lorna Dougan
- School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, U.K.,Astbury Centre for Structural and Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K
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7
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Sundar S, Sandilya AA, Priya MH. Unraveling the Influence of Osmolytes on Water Hydrogen-Bond Network: From Local Structure to Graph Theory Analysis. J Chem Inf Model 2021; 61:3927-3944. [PMID: 34379415 DOI: 10.1021/acs.jcim.1c00527] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Water structure in aqueous osmolyte solutions, deduced from the slight alteration in the water-water radial distribution function, the decrease in water-water hydrogen bonding, and tetrahedral ordering based only on the orientation of nearest water molecules derived from the molecular dynamics simulations, appears to have been perturbed. A careful analysis, however, reveals that the hydrogen bonding and the tetrahedral ordering around a water molecule in binary solutions remain intact as in neat water when the contribution of osmolyte-water interactions is appropriately incorporated. Furthermore, the distribution of the water binding energies and the water excess chemical potential of solvation in solutions are also pretty much the same as in neat water. Osmolytes are, therefore, well integrated into the hydrogen-bond network of water. Indeed, osmolytes tend to preferentially hydrogen bond with water molecules and their interaction energies are strongly correlated to their hydrogen-bonding capability. The graph network analysis, further, illustrates that osmolytes act as hubs in the percolated hydrogen-bond network of solutions. The degree of hydrogen bonding of osmolytes predominantly determines all of the network properties. Osmolytes like ethanol that form fewer hydrogen bonds than a water molecule disrupt the water hydrogen-bond network, while other osmolytes that form more hydrogen bonds effectively increase the connectivity among water molecules. Our observation of minimal variation in the local structure and the vitality of osmolyte-water hydrogen bonds on the solution network properties clearly imply that the direct interaction between protein and osmolytes is solely responsible for the protein stability. Further, the relevance of hydrogen bonds on solution properties suggests that the hydrogen-bonding interaction among protein, water, and osmolyte could be the key determinant of the protein conformation in solutions.
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Affiliation(s)
- Smrithi Sundar
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Avilasha A Sandilya
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - M Hamsa Priya
- Department of Biotechnology, Bhupat and Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
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