Small angle neutron scattering contrast variation reveals heterogeneities of interactions in protein gels

Banc, Amélie; Charbonneau, Céline; Dahesh, Mohsen; Appavou, M-S; Fu, Zhendong; Morel, M-H; Ramos, Laurence

doi:10.1039/c6sm00710d

Cited by 31 publications

(28 citation statements)

References 56 publications

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“…Accordingly, we have previously evidenced the presence of low density supramolecular assemblies of proteins, with size of the order of 100 nm, for extracts with equal content of gliadin and glutenin solubilized in ethanol/water (Dahesh et al, 2014). In the semi-dilute regime assemblies induce the presence of regions, of comparable size, with strong hydrogen bonds between proteins (Banc et al, 2016). In addition, in ethanol/water we expect the gluten network architecture to be preserved since rheological properties, in particular the elastic plateau, are coherent with that of native gluten in water (Dahesh et al, 2016).…”

Section: Introductionmentioning

confidence: 94%

Insight into gluten structure in a mild chaotropic solvent by asymmetrical flow field-flow fractionation (AsFlFFF) and evidence of non-covalent assemblies between glutenin and ω-gliadin

et al. 2020

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Wheat gluten, one of the most complex viscoelastic protein networks in nature, is unique to get the specific texture of bread. Due to its complex protein composition, its insolubility in most solvents and the very high molar mass of half of the proteins (glutenin, the other half being gliadin), the architecture of the network is still not well understood. In this work, we have investigated model gluten protein extracts with contrasted compositions in glutenin and gliadin solubilized in a mild chaotropic solvent: ethanol/water (50/50 v/v). The samples display a liquid-liquid phase separation with an upper critical solution temperature that depends on the protein composition. The phase diagrams are consistent with the presence of supramolecular assemblies of proteins. To confirm the presence of these assemblies and fully characterize the objects dispersed in ethanol/water, we have used an asymmetrical flow field-flow fractionation (AsFlFFF) setup coupled with differential refractive index, multi-angle light scattering and dynamic light scattering detections to probe very dilute protein suspensions. We have identified three classes of objects, with distinctive molar mass, characteristic size and conformation: protein monomers, polymeric structures, and very loose protein assemblies with molar mass larger than 2.10 6 g/mol. A molecular characterization of the species by size exclusion chromatography in a denaturing solvent shows that polymers and assemblies are mainly composed of glutenin and -gliadin. The high content of 2 -gliadin, devoid of cysteines, indicates the importance of non-covalent interactions involved in protein assemblies and might play a major role in gluten rheology.

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Section: Introductionmentioning

confidence: 94%

Insight into gluten structure in a mild chaotropic solvent by asymmetrical flow field-flow fractionation (AsFlFFF) and evidence of non-covalent assemblies between glutenin and ω-gliadin

et al. 2020

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“…SANS/SAXS mismatch likely results from two superimposing phenomena, which both highlight the polypeptide backbone compared to the polysaccharides. Firstly, hydrogen-deuterium exchange is expected to take place on labile hydrogen (Banc et al, 2016), which are present on both hydroxyl (sugars) and amine groups (proteins). This exchange will tend to decrease the contrast between polypeptide/polysaccharides and deuterated water.…”

Section: Structure Of Gum Arabic Probed By Sans and Saxsmentioning

confidence: 99%

Gum Arabic in solution: Composition and multi-scale structures

et al. 2019

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Gum Arabic is a natural acacia tree exudate containing hyperbranched polysaccharides and proteins. Here, we perform a dual chromatographic separation together with small-angle X-ray and neutron scattering structural characterizations. We show that the different species present in Gum Arabic can not be easily classified in distinct families. They are rather build from various combinations of two building blocks that are evidenced by a mismatch between small-angle X-ray and neutron scattering. One block corresponds to hyperbranched polysaccharides, which we describe as three-dimensional multi-scale porous colloids possessing three length scales of 7, 2 and 0.7 nm. The other block corresponds to protein chains that organize as Gaussian chains in solution and are prone to aggregation. A large array of polysaccharide/protein conjugates was identified, which differs in size, hydrophobicity and amino-acid content. Still, their structure is always the juxtaposition of the two building blocks structures. Additionally, small-angle neutron scattering reveals that large-scale structures are ubiquitous in Gum Arabic solutions and originate from the self-association of both free and conjugated polypeptide chains. Despite its compositional complexity, Gum Arabic solutions thus possess a robust multi-scale structure that is mainly impacted by concentration and ionic repulsions.

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“…Furthermore, we should emphasize that the expression of Eq. (3) is not directly derived (even though it combines two of the well-accepted theoretical terms, i.e., the DebyBueche term (Banc et al, 2016;Debye & Bueche, 1948;Geissler et al, 1997;B. Hammouda et al, 2002;Shibayama & Sakai, 2013) and the classic Debye scattering contribution (Josef & Bianco-Peled, 2012;Muroga et al, 2004)), but is in the sense of a more semi-empirical nature.…”

Section: The String-of-beads Modelmentioning

confidence: 98%

“…Hammouda, Ho, & Kline, 2002). Among these extensions, the so-called Debye-Beuche formalism containing the Lorentzian and squared-Lorentzian terms is the best known (Banc et al, 2016;Debye & Bueche, 1948;Geissler et al, 1997;B. Hammouda et al, 2002;Shibayama & Sakai, 2013).…”

Section: Introductionmentioning

confidence: 98%

Supramolecular structure of methyl cellulose and lambda- and kappa-carrageenan in water: SAXS study using the string-of-beads model

Dogša

Cerar

Jamnik

2017

Carbohydrate Polymers

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Small angle neutron scattering contrast variation reveals heterogeneities of interactions in protein gels

Abstract: The structure of model gluten protein gels prepared in ethanol/water is investigated by small angle X-ray (SAXS) and neutrons (SANS) scattering. We show that gluten gels display radically different SAXS and SANS profiles when the solvent is (at least partially) deuterated.

Cited by 31 publications

References 56 publications

Insight into gluten structure in a mild chaotropic solvent by asymmetrical flow field-flow fractionation (AsFlFFF) and evidence of non-covalent assemblies between glutenin and ω-gliadin

Insight into gluten structure in a mild chaotropic solvent by asymmetrical flow field-flow fractionation (AsFlFFF) and evidence of non-covalent assemblies between glutenin and ω-gliadin

Gum Arabic in solution: Composition and multi-scale structures

Supramolecular structure of methyl cellulose and lambda- and kappa-carrageenan in water: SAXS study using the string-of-beads model

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