A high pressure cell using metallic windows to investigate the structure of molecular solutions up to 600 MPa by small-angle neutron scattering

Annighöfer, Burkhard; Hélary, Arnaud; Brûlet, Annie; Noue, Alexandre Colas de la; Loupiac, Camille; Combet, Sophie

doi:10.1063/1.5051765

Cited by 8 publications

(2 citation statements)

References 23 publications

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“…HP-SANS experiments were performed using a new HP-SANS cell that we developed recently. 33 HP-SANS spectra were recorded for several tens of minutes at 5, 100, 150, 200, 250, and 300 MPa (the pressure change was made also at a rate of 10 MPa/min). Each BLG sample was also measured in a quartz Hellma ® cell (with a pathlength of 2 mm) before and after HP treatment.…”

Section: Eqmentioning

confidence: 99%

Structure of proteins under pressure: Covalent binding effects of biliverdin on β-lactoglobulin

Minić¹,

Annighöfer²,

Hélary³

et al. 2022

Biophysical Journal

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Section: Eqmentioning

confidence: 99%

Structure of proteins under pressure: Covalent binding effects of biliverdin on β-lactoglobulin

Minić¹,

Annighöfer²,

Hélary³

et al. 2022

Biophysical Journal

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“…The particle is chosen such that is does not adsorb on the test sample (here, a supramolecular polymer) and does sense its fluctuations (having a size larger than that of the test material). Typically, the MSD is measured by dynamic light scattering (DLS) techniques. ,− Different specialized sample cells for handling elevated pressures have been developed and utilized in neutron or X-ray scattering facilities or in conjunction with static or dynamic light scattering setups. ,− DLS-based microrheological LVE data were reported in the past, and very recently, a comprehensive study reported the design and implementation of a versatile experimental setup to obtain reliable data with fracturing fluids at pressures of up to 200 MPa . Both investigations , used passive microrheology based on diffusive wave spectroscopy (DWS).…”

Section: Introductionmentioning

confidence: 99%

Dynamics and Rheology of Supramolecular Assemblies at Elevated Pressures

et al. 2022

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A methodology to investigate the linear viscoelastic properties of complex fluids at elevated pressures (up to 120 MPa) is presented. It is based on a dynamic light scattering (DLS) setup coupled with a stainless steel chamber, where the test sample is pressurized by means of an inert gas. The viscoelastic spectra are extracted through passive microrheology. We discuss an application to hydrogen-bonding motif 2,4-bis(2-ethylhexylureido)toluene (EHUT), which self-assembles into supramolecular structures (tubes and filaments) in apolar solvents dodecane and cyclohexane. High levels of pressure (roughly above 20 MPa) are found to slow down the terminal relaxation process; however, the increases in the entanglement plateau modulus and the associated persistence length are not significant. The concentration dependence of the plateau modulus, relaxation times (fast and slow), and correlation length is practically the same for all pressures and exhibits distinct power-law behavior in different regimes. Within the tube phase in dodecane, the relative viscosity increment is weakly enhanced with increasing pressure and reaches a plateau at about 60 MPa. In fact, depending on concentration, the application of pressure in the tube regime may lead to a transition from a viscous (unentangled) to a viscoelastic (partially entangled to well-entangled) solution. For well-entangled, long tubes, the extent of the plateau regime (ratio of high- to low-moduli crossover frequencies) increases with pressure. The collective information from these observations is summarized in a temperature–pressure state diagram. These findings provide ingredients for the formulation of a solid theoretical framework to better understand and exploit the role of pressure in the structure and dynamics of supramolecular polymers.

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Effect of Ligands on HP-Induced Unfolding and Oligomerization of β-Lactoglobulin

Minić

Annighöfer

Hélary

et al. 2020

Biophysical Journal

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To probe intermediate states during unfolding and oligomerization of proteins remains a major challenge. High pressure (HP) is a powerful tool for studying these problems, revealing subtle structural changes in proteins not accessible by other means of denaturation. Bovine blactoglobulin (BLG), the main whey protein, has a strong propensity to bind various bioactive molecules, such as retinol and resveratrol, two ligands with different affinity and binding sites. By combining in situ HP-small-angle neutron scattering (SANS) and HP-UV/visible absorption spectroscopy, we report the specific effects of these ligands on 3D conformational and local changes in BLG induced by HP. Depending on BLG concentration, two different unfolding mechanisms are observed in situ under pressures up to ~300 MPa, mediated by the formation of disulfide bonds: either a complete protein unfolding, from native dimers to Gaussian chains, or a partial unfolding with oligomerization in tetramers. Retinol, which has a high affinity for BLG hydrophobic cavity, significantly stabilizes BLG both in 3D and local environments, by shifting the onset of protein unfolding by ~100 MPa. Increasing temperature from 30 to 37°C enhances the hydrophobic stabilization effects of retinol. In contrast, resveratrol, which has a low binding affinity for site(s) on the surface of the BLG, does not induce any significant effect on the structural changes of BLG due to pressure. HP treatment back and forth up to ~300 MPa causes irreversible covalent oligomerization of BLG. Ab initio modeling of SANS shows that the oligomers formed from BLG/retinol complex are smaller and more elongated compared to BLG without ligand or in the presence of resveratrol. By combining HP-SANS and HP-UV/vis absorption spectroscopy, our strategy highlights the crucial role of BLG hydrophobic cavity and opens up new possibilities for the structural determination of HP-induced protein folding intermediates and irreversible oligomerization..

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A high pressure cell using metallic windows to investigate the structure of molecular solutions up to 600 MPa by small-angle neutron scattering

Cited by 8 publications

References 23 publications

Structure of proteins under pressure: Covalent binding effects of biliverdin on β-lactoglobulin

Structure of proteins under pressure: Covalent binding effects of biliverdin on β-lactoglobulin

Dynamics and Rheology of Supramolecular Assemblies at Elevated Pressures

Effect of Ligands on HP-Induced Unfolding and Oligomerization of β-Lactoglobulin

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