Le Floch-Fouéré Cécile, Pezennec Stéphane, Pasco Maryvonne, Paboeuf Gilles, Renault Anne, Beaufils Sylvie
INRA, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France; AGROCAMPUS OUEST, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France.
INRA, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France; AGROCAMPUS OUEST, UMR1253 Science et Technologie du Lait et de l'Œuf, F-35042 Rennes, France.
J Colloid Interface Sci. 2015 Jan 1;437:219-226. doi: 10.1016/j.jcis.2014.09.035. Epub 2014 Sep 28.
We have compared the behavior of ovotransferrin at the air-solution interface in the presence of a monovalent ion (acetate), or a divalent ion (citrate), the latter being known to induce conformational changes of this protein upon interaction with its iron-binding sites. We have characterised the adsorption layer at the air-water interface in terms of homogeneity, surface concentration excess and rheological properties at pH 4.0. Besides we have investigated the bulk conformation in the presence of the two anions. In the presence of citrate only, interfacial layers display well-defined domains of higher overall surface concentration suggesting multilayers adsorption. Citrate also induces higher helical content and stabilizes the protein against thermal denaturation. Hence we propose that these changes are involved in the propensity of ovotransferrin to self-assemble at the air-water interface resulting in thick and heterogeneous interfacial layer.
我们比较了卵转铁蛋白在一价离子（醋酸盐）或二价离子（柠檬酸盐）存在下在气-溶液界面的行为，已知后者在与铁结合位点相互作用时会诱导该蛋白质的构象变化。我们在pH 4.0条件下，从均匀性、表面浓度过剩和流变学性质方面对气-水界面的吸附层进行了表征。此外，我们还研究了两种阴离子存在下的整体构象。仅在柠檬酸盐存在时，界面层显示出具有更高总表面浓度的明确区域，表明存在多层吸附。柠檬酸盐还诱导更高的螺旋含量，并使蛋白质对热变性稳定。因此，我们认为这些变化与卵转铁蛋白在气-水界面自组装的倾向有关，从而导致形成厚且不均匀的界面层。
