The conformational structure of A-gliadin

Cole, Earl W.; Kasarda, Donald D.; Lafiandra, D.

doi:10.1016/0167-4838(84)90315-7

Cited by 26 publications

(8 citation statements)

References 26 publications

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“…9), suggesting that the interactions responsible for the oligomerization of the natural gliadins were much weaker than those causing the aggregation of the reduced malfolded polypeptides. Our conclusion regarding the role of intramolecular disulfide bonds in the deposition of S-rich gliadins is also supported by biophysical studies (24), suggesting that these disulfide bonds play a role in the conformational structure of these proteins.…”

Section: The Intramolecular Disulfide Bonds In S-rich Gliadins Stabilsupporting

confidence: 65%

Intramolecular Disulfide Bonds between Conserved Cysteines in Wheat Gliadins Control Their Deposition into Protein Bodies

Shimoni

Galili

1996

Journal of Biological Chemistry

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Following synthesis, wheat gliadin storage proteins are deposited into protein bodies inside the endomembrane system in a way that enables not only their efficient accumulation and dehydration during seed maturation, but also their rapid rehydration and degradation during germination. In the present report, we studied the mechanism of gliadin deposition and whether it was controlled by the conformation of these proteins. Although gliadins are generally known to be insoluble in aqueous solutions, sucrose gradient analysis showed that a considerable amount of these proteins appeared as relatively soluble monomers in developing grains. In vitro reduction of the intramolecular disulfide bonds that are present in natural monomeric gliadins caused their precipitation into insoluble aggregates. In addition, pulse-chase experiments in the absence or presence of reducing agents showed that formation of intramolecular disulfide bonds also played a major role in folding and deposition of the gliadins in vivo. Our results imply that following sequestration into the endoplasmic reticulum, the gliadins fold into relatively soluble monomers, which are incompetent for rapid aggregation and gradually assemble into protein bodies. This pattern of deposition apparently depends on the conformation of the gliadins, which is stabilized by intramolecular disulfide bonds formed between the conserved cysteines. The contribution of this study to the understanding of the evolution and function of gliadins is discussed.

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Section: The Intramolecular Disulfide Bonds In S-rich Gliadins Stabilsupporting

confidence: 65%

Intramolecular Disulfide Bonds between Conserved Cysteines in Wheat Gliadins Control Their Deposition into Protein Bodies

Shimoni

Galili

1996

Journal of Biological Chemistry

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“…5b), even if the diffusion seems to be slightly faster at pH 4. This can be related to a higher extended N-terminal domain of alpha gliadin at pH 3 [45] and a decrease in intrinsic viscosity, as it was previously observed at pH 4 compared to pH 3 [46].…”

Section: Proton Nmr Relaxation Studies Below the Freezing Transition mentioning

confidence: 53%

1H NMR relaxation studies of protein–polysaccharide mixtures

Ducel

Pouliquen

Richard

et al. 2008

International Journal of Biological Macromolecules

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“…Since the purification steps alter the structure of the proteins and may modify the organisation of the intramolecular covalent links, no firm conclusions can be made from this observation. It has been found by IR spectroscopy that the reduction and alkylation has little effect on the secondary structure of y-gliadin in solution [26], or on the conformation of A-gliadin reflected by intrinsic viscosity [29]. Fluorescence studies showed that the reduction/ alkylation and the denaturation by 8 M urea of y-gliadin transferred their tryptophane residues to a more polar environment [30].…”

Section: Discussionmentioning

confidence: 99%

Molecular flexibility in wheat gluten proteins submitted to heating

Hargreaves¹,

Popineau²,

Meste³

et al. 1995

FEBS Letters

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Prolamin proteins are responsible for the network that gives wheat dough its viscoelastic properties. Non-prolamin depleted gluten was prepared under conditions that preserve its functionality. Electron Spin Resonance (ESR) was used to provide information about the dynamics of the protein at temperatures between 5 and 90°C by specific spin labelling of its cysteine residues. The spectra were of a composite type, resulting from at least two populations of spin labels largely differing in molecular mobility. The correlation time of the less mobile nitroxide radicals was determined by saturation transfer ESR. Upon heating there was a transfer from the slow to the fast moving population of radicals, and an increase of mobility of this last catagory that followed the Arrbenins law. The effect of temperature on molecular flexibility was reversible. This was not the case for purified, polymerised glutenin subunits extracted from gluten. Urea created similar modifications on gluten as heat.Key words: Prolamin; Gluten; ESR; ST-ESR; Temperature; Urea segmental mobility in the proteins in D20 was high (~65%) and increased with temperature.Electron spin resonance (ESR) spectroscopy can yield information about polymer networks by the use of a stable paramagnetic compound [9]. Spin probing informs about the solvent environment, whilst covalent spin labelling reflects the segmental mobility of labelled molecules. Previous work has proven the usefulness of ESR spectroscopy in understanding the properties of functional gluten. Spin probing showed a compartimentation of the liquid phase of hydrated gluten, namely, the existence of a lipid and of an aqueous phase [10,11], and of two different microenvironments in the water phase [12,13]. The polypeptide flexibility was found to depend on the gliadin/ glutenin ratio and on the organisation of glutens 00,11].To improve our understanding of the organisation of gluten and of the interactions in the protein network, we investigated, in this paper, the effect of temperature and chemical denaturation on the molecular flexibility of gluten and glutenin subunits by ESR and saturation transfer (ST)-ESR.

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The conformational structure of A-gliadin

Cited by 26 publications

References 26 publications

Intramolecular Disulfide Bonds between Conserved Cysteines in Wheat Gliadins Control Their Deposition into Protein Bodies

Intramolecular Disulfide Bonds between Conserved Cysteines in Wheat Gliadins Control Their Deposition into Protein Bodies

1H NMR relaxation studies of protein–polysaccharide mixtures

Molecular flexibility in wheat gluten proteins submitted to heating

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