14 research outputs found
New exploration of the Îł-gliadin structure through its partial hydrolysis
The partial enzymatic hydrolysis of wheat gliadins constitutes an interesting tool to unravel their structural specificity. In this work, the structure and conformation of Îł-gliadin were investigated through its limited chymotrypsic digestion. Using a combination of computational, biochemical and biophysical tools, we studied each of its N and C terminal domains. Our results reveal that Îł-gliadin is a partially disordered protein with an unfolded N-terminal domain surprisingly resistant to chymotrypsin and a folded C-terminal domain. Using spectroscopic tools, we showed that structural transitions occured over the disordered N-terminal domain for decreasing ethanol/water ratios. Using SAXS measurements, low-resolution 3D structures of Îł-gliadin were proposed. To relate the repeated motifs of the N-terminal domain of Îł-gliadin to its structure, engineered peptide models PQQPY/F were also studied. Overall results demonstrated similarities between the N-terminal domain and its derived model peptides. Our findings support the use of these peptides as general templates for understanding the wheat protein assembly and dynamics
Protein-chemical features of five different wheat products affect the sensitising capacity through the skin
SEEDQUAL : Caractérisation de la diversité génétique de la composition de la graine et du tourteau de colza pour des usages en alimentation animale
National audienc
Towards a reproducible and highâthroughput workflow to quantify globulins and napins, the two major seed storage proteins in oilseed rape
International audienceSeed storage proteins (SSP) in oilseed rape consist of 12S globulins (cruciferins) and 2S albumins (napins) that stand for around 70% of total seed proteins. Since napins contain more sulfur residues than cruciferins, they display a higher value for food or feed usages. Recent results demonstrated the potentialities of genetics to improve the 12S/2S ratio. However, the current methods to assess the SSP balance are still time consuming and difficult to handle, thus preventing the phenotyping of large sets of accessions. Plant material 100 accessions of winter oilseed rape : Conclusion: Encouraging results for 2S quantification with NIRS. The current calibrations can be used to roughly sort out the accessions upon 12S/2S content but need further improvements (e.g., wider calibration sets)
Ăvaluation de deux mĂ©thodes dâauto-tannage de fractions de tourteaux de tournesol et de colza enrichies en protĂ©ines et composĂ©s phĂ©noliques par mesure de la dĂ©gradabilitĂ© ruminale des protĂ©ines in vitro
International audienceTwo protein tanning methods were evaluated to contribute to the withdrawal of formaldehyde as a tanning agent of meals for feeding ruminants. The experimental materials were two fractions of rapeseed and sunflower meals collected at the positive electrode of an electrostatic separator, presenting high contents in proteins and phenolic compounds. The objective was to make phenolics and proteins interact without addition of exogenous tannins. Treatment CH incubated a meal fraction:water mixture (1:2, w:w) for 48 h at 50 degrees C. Treatment FR incubated a meal fraction:water mixture (1:10, w:w) at pH 9.0 for 48 h at 4 degrees C. Microbial proteolysis on meal fractions were quantified during 24 h rumen batch fermentations with cellulose and starch as nitrogen-free energy sources. The net production of ammonia tended to be reduced by treatment FR mostly on rapeseed, corresponding to an 8% saving of rapeseed meal proteins degradable in the rumen. When untreated, the sunflower fraction decreased methane production by 50%, while treatments restored the fermentation pattern. Cold alkaline treatment could be considered to protect meal proteins from degradation by rumen micro-organisms.Deux mĂ©thodes de tannage des protĂ©ines ont Ă©tĂ© Ă©valuĂ©es pour contribuer au remplacement du formaldĂ©hyde comme agent tannant des tourteaux destinĂ©s Ă lâalimentation des ruminants. Les matĂ©riaux expĂ©rimentaux Ă©taient deux fractions de tourteaux de colza et tournesol collectĂ©es Ă lâĂ©lectrode positive dâun sĂ©parateur Ă©lectrostatique, prĂ©sentant des teneurs Ă©levĂ©es en protĂ©ines et en composĂ©s phĂ©noliques. Le but Ă©tait de faire interagir les composĂ©s phĂ©noliques et les protĂ©ines sans addition de tanins exogĂšnes. Le traitement CH a consistĂ© Ă incuber un mĂ©lange tourteau/eau (1/2, poids/poids) pendant 48âh Ă 50â°C. Le traitement FR a consistĂ© Ă incuber un mĂ©lange tourteau/eau (1/10, poids/poids) Ă pHâ9,0 pendant 48âh Ă 4â°C. La protĂ©olyse des fractions de tourteau par les microbes du rumen a Ă©tĂ© quantifiĂ©e lors de fermentations in vitro de 24âh avec de la cellulose et de lâamidon comme sources dâĂ©nergie sans azote. Le traitement FR a eu tendance Ă rĂ©duire la production nette dâammoniac, principalement avec le colza, Ă©quivalant Ă la protection de 8â% des protĂ©ines de tourteau de colza dĂ©gradables dans le rumen. La fraction de tournesol non traitĂ©e a diminuĂ© la production de mĂ©thane de 50â%, cependant les traitements ont restaurĂ© le profil fermentaire. Le traitement alcalin Ă froid pourrait ĂȘtre envisagĂ© afin de protĂ©ger les protĂ©ines du tourteau de la dĂ©gradation par les micro-organismes du rume
Lien entre composition en protĂ©ines de rĂ©serve et teneurs en glucosinolates dans la graine de colza : vers lâidentification de dĂ©terminants gĂ©nĂ©tiques et molĂ©culaires
National audienceIn rapeseed, the seed storage proteins are cruciferins (12S globulins) and napins (2S albumins) which represent more than 70% of the total proteins. As napins are richer in sulfur and aromatic residues than cruciferins, they are of greater nutritional interest. However, several studies show that in modern varieties '00' (no erucic acid and low glucosinolates), the napins content is lower than in old varieties '++' (high erucic acid and glucosinolates). The aim of our study is to identify the genetic and molecular bases of the relationship between the glucosinolate and 2S contents in rapeseed.Association genetic analysis identified eight genomic regions controlling both napin and glucosinolate contents. These regions cover nearly 650 genes, seven are described involved in sulfur metabolism pathways and were targeted in this study. In particular, the MYB28 gene, located on chromosome C09, shows a 4-bp insertion polymorphism between the '00' and '++' varieties. Furthermore, MYB28 insertion mutants in Arabidopsis produce seeds with significantly reduced sulfur, glucosinolates and napins contents. These results could provide clues for improving the reserve protein composition of rapeseed.Chez le colza, les protĂ©ines de rĂ©serve de la graine sont les crucifĂ©rines (globulines 12S) et les napines (albumines 2S) qui reprĂ©sentent plus de 70% des protĂ©ines totales. Les napines Ă©tant plus riches en rĂ©sidus soufrĂ©s et aromatiques que les crucifĂ©rines, elles prĂ©sentent un intĂ©rĂȘt supĂ©rieur sur le plan nutritionnel. Cependant plusieurs Ă©tudes montrent que chez les variĂ©tĂ©s modernes de colza, â00â, dont les graines sont dĂ©pourvues en acide Ă©rucique et pauvres en glucosinolates, la teneur en napines est plus faible que chez les variĂ©tĂ©s anciennes â++â. Lâobjectif de notre Ă©tude est dâidentifier les bases gĂ©nĂ©tiques et molĂ©culaires de la relation entre la teneur en glucosinolates et en napines dans la graine de colza.Une analyse par gĂ©nĂ©tique dâassociation a permis dâidentifier huit rĂ©gions gĂ©nomiques contrĂŽlant Ă la fois les teneurs en napines et en glucosinolates. Ces rĂ©gions couvrent prĂšs de 650 gĂšnes dont sept sont dĂ©crits comme Ă©tant impliquĂ©s dans les voies du mĂ©tabolisme soufrĂ© et ont Ă©tĂ© ciblĂ©s pour la suite de cette Ă©tude. En particulier, le gĂšne MYB28, localisĂ© sur le chromosome C09, montre un polymorphisme dâinsertion de 4 pb entre les variĂ©tĂ©s â00â et â++â. Par ailleurs, des mutants dâinsertion MYB28 chez Arabidopsis produisent des graines dont les teneurs en soufre, glucosinolates et napines sont significativement rĂ©duites. Ces rĂ©sultats pourraient fournir des pistes pour amĂ©liorer la composition en protĂ©ines de rĂ©serve de la graine de colza
Assembly of plant storage proteins: role of intrinsic disorder and charge anisotropy
Assembly of plant storage proteins: role of intrinsic disorder and charge anisotropy. Edible Soft Matter â a SoftComp Topical Worksho
Assembly of plant storage proteins: role of intrinsic disorder and charge anisotropy
Assembly of plant storage proteins: role of intrinsic disorder and charge anisotropy. Edible Soft Matter â a SoftComp Topical Worksho
Biochemical and physicalâchemical characterisation of leaf proteins extracted from Cichorium endivia leaves
International audienceThis study provides a detailed characterisation of a leaf protein concentrate (LPC) extracted from Cichorium endivia leaves using a pilot scale process. This concentrate contains 74.1% protein and is mainly composed of Ribulose-1,5-BISphosphate Carboxylase/Oxygenase (RuBisCO). We show that the experimentally determined extinction coefficient (around 5.0 cmâ1 gâ1 L depending on the pH) and refractive index increment (between 0.27 and 0.39 mL gâ1) are higher than the predicted ones (about 1.6 cmâ1 gâ1 L and 0.19 mL gâ1, respectively). In addition, the UVâvisible absorption spectra show a maximum at 258 nm. These data suggest the presence of non-protein UV-absorbing species. Chromatographic separation of the concentrate components in denaturing conditions suggests that RuBisCO SC may be covalently bounded to few phenolic compounds. Besides, the solubility of LPC proteins is higher than 90% above pH 6. Such high solubility could make LPC a good candidate as a functional food ingredient