Solid-state NMR spectroscopy insights for resolving different water pools in alginate hydrogels

Nokab, Mustapha El Hariri El; Lasorsa, Alessia; Sebakhy, Khaled O.; Picchioni, Francesco; Wel, Patrick C.A. van der

doi:10.1016/j.foodhyd.2022.107500

Cited by 18 publications

(10 citation statements)

References 88 publications

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“…To directly assess the connection between the changes in protein motion and solvent dynamics, we used 1 H-detected MAS ssNMR to monitor the solvent mobility as a function of temperature ( Böckmann et al, 2009 , El Hariri El Nokab et al, 2022 , Mandal and van der Wel, 2016 ). Fig.…”

Section: Resultsmentioning

confidence: 99%

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Matlahov

Boatz

Wel

2022

Journal of Structural Biology: X

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Section: Resultsmentioning

confidence: 99%

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Matlahov

Boatz

Wel

2022

Journal of Structural Biology: X

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“…To directly assess the connection between the changes in protein motion and solvent dynamics, we used 1 H-detected MAS ssNMR to monitor the solvent mobility as a function of temperature (Böckmann et al, 2009; El Hariri El Nokab et al, 2022; Mandal & van der Wel, 2016). Figure 2 D shows the 1D proton spectra of the same fibril sample between 277 and 256K.…”

Section: Resultsmentioning

confidence: 99%

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Matlahov

Boatz

Wel

2022

Preprint

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Many amyloid-forming proteins, which are normally intrinsically disordered, undergo a disorder-to-order transition to form fibrils with a rigid β-sheet core flanked by disordered domains. Solid-state NMR (ssNMR) and cryogenic electron microscopy (cryoEM) excel at resolving the rigid structures within amyloid cores but studying the disordered domains on fibril surfaces remains more challenging. This challenge is exemplified by a fragment of mutant huntingtin exon 1 (HttEx1), which self-assembles into pathogenic neuronal inclusions in Huntington disease (HD). The mutant protein’s expanded polyglutamine (polyQ) segment forms a highly rigid fibril core with dynamic surface residues and disordered ‘flanking’ segments. Here we deploy dynamically sensitive magic angle spinning ssNMR experiments and variable temperature studies to elucidate how solvent dynamics impact the fibrils’ segmental dynamics, and permit the identification of surface-facing (polyQ) residues. A novel implementation of dynamic spectral editing (DYSE) ssNMR is described and applied, in order to reveal the weak signals of surface-facing glutamine residues despite the strong background of rigid core signals. This type of ‘intermediate motion selection’ (IMS) experiment, based on cross-polarization (CP) ssNMR, is complementary to more traditional DYSE methods that highlight highly flexible or highly rigid protein segments. Integration of the IMS-DYSE element in standard CP-based ssNMR experiments permits the observation of previously invisible fiber surface signals and may be extended to a wider variety of biomolecular assemblies and (bio)materials. In pathogenic protein amyloid fibrils the detection of surfaces of the (polyQ) amyloid core is relevant to e.g. the development of fluorescent dyes and positron emission tomography tracers that selectively bind these surfaces.HighlightsMutant huntingtin exon 1 fibrils feature a broad range of molecular dynamics.Molecular motion is coupled to dynamics of the fiber-associated water solvent.Dynamics-based spectral editing ssNMR reveals mobile surface residues.Intermediate-motion selection uses dipolar-dephasing of rigid sites.Surface-facing glutamines outside the fiber core observed and identified.

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“…This supercritical CO 2 24 drying process in comparison with conventional oven drying shall find potential applications in preserving the pores of the modified starch, hence not altering the final properties of the modified starch materials. Our future studies will include determining the DS, heterogeneity and local mobility, 25 degree of crystallinity 26 and solvent matrix interactions 27 of different modified starch‐based materials from various origins using advanced 28 and beyond conventional solid‐state NMR techniques, 29 a detailed economic study and analysis comparing various drying techniques, such as conventional oven drying, freeze drying, and supercritical CO 2 drying. Furthermore, the porosity of the final starch materials dried via the three different techniques will be compared and the mechanical properties of the materials will be further assessed.…”

Section: Conclusion and Future Perspectivesmentioning

confidence: 99%

A green/sustainable organocatalytic pathway for the preparation of esterified supercriticalCO₂‐dried potato starch products

Alassmy

Abduljawad

Alshamrani

et al. 2023

J of Applied Polymer Sci

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Production of renewable and modified starch-based products was achieved using a sustainable catalyst and an environmentally friendly drying process via supercritical CO 2 . Potato starch was modified via a sustainable and green esterification process with acetic anhydride reagent implementing a novel organocatalytic pathway at different periods of time (0.5, 3 and 7 h) by applying an esterification reaction at 120 C targeting intermediate degrees of substitution (i.e., 0.2 < DS <1.5) finding potential applications as polymer packaging materials. The final modified samples were divided into two fractions, where the first fraction was dried under vacuum at 80 C for 24 h and the second fraction was dried under supercritical CO 2 at 40 C and 100 bars for 2 h. The final products were analyzed using an array of characterization techniques such as Fourier transform infrared (FTIR), Proton nuclear magnetic resonance ( 1 H-NMR), scanning electron microscopy (SEM), X-ray diffraction (XRD), N 2 physisorption, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and Karl Fischer. The chemical structure of both fractions was similar as confirmed by the different characterization techniques. Drying under supercritical CO 2 preserved some pores in the modified starch materials as opposed to thermal oven drying, as was confirmed by N 2 physisorption measurements. The degree of substitution (DS) was determined using three different techniques; titration, high performance liquid chromatography (HPLC) and solution state proton nuclear magnetic resonance ( 1 H NMR) spectroscopy and the values were greater than 0.2 and less than 1.5 indicating intermediate degrees of substitution.

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Solid-state NMR spectroscopy insights for resolving different water pools in alginate hydrogels

Cited by 18 publications

References 88 publications

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

A green/sustainable organocatalytic pathway for the preparation of esterified supercriticalCO₂‐dried potato starch products

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Solid-state NMR spectroscopy insights for resolving different water pools in alginate hydrogels

Cited by 18 publications

References 88 publications

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

Selective observation of semi-rigid non-core residues in dynamically complex mutant huntingtin protein fibrils

A green/sustainable organocatalytic pathway for the preparation of esterified supercriticalCO2‐dried potato starch products

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Product

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A green/sustainable organocatalytic pathway for the preparation of esterified supercriticalCO₂‐dried potato starch products