QUINOA-LAQV/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal.
UCBIO/REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Porto, Portugal.
Int J Biol Macromol. 2018 Jun;112:1029-1037. doi: 10.1016/j.ijbiomac.2018.02.055. Epub 2018 Feb 12.
Celiac Disease (CD) is now recognized as a worldwide epidemic. Although a gluten free diet usually induces clinical improvements within days or weeks, adhering to this routine is still troublesome. Therefore, new solutions are needed for quality-of-life improvement of CD patients. The present work intends to bring molecular and thermodynamic insights on the ability of green tea epigalhocatechin-3-gallate (EGCG) to interact and modulate the bioavailability of a major CD immunodominant peptide (32-mer). Characterization of peptide binding was assessed by means of both 1D and 2D H NMR experiments, ITC and Molecular Dynamics simulations. Accordingly, EGCG not only exhibits a high reactivity towards the 32-mer peptide as its binding appears to be entropy-driven and involves two sequential binding events, each with different binding strengths. Structural rearrangements were also detected during the interaction, contributing to a greater stability of the formed complexes. In vitro transepithelial transport assays using a Caco-2 cell line model were also performed and highlighted the ability of EGCG to significantly reduce the concentration of free peptide in the basolateral compartment. Overall, this study provides important evidences regarding the structural features and molecular mechanisms by which EGCG could interact and potentially modulate the function of some bioactive CD peptides.
乳糜泻（CD）现已被认为是一种全球性疾病。尽管无麸质饮食通常会在数天或数周内引起临床改善，但坚持这种饮食仍然很麻烦。因此，需要为 CD 患者的生活质量改善提供新的解决方案。本研究旨在从分子和热力学角度深入了解绿茶表没食子儿茶素没食子酸酯（EGCG）与主要乳糜泻免疫优势肽（32 肽）相互作用和调节其生物利用度的能力。通过一维和二维 H NMR 实验、ITC 和分子动力学模拟评估了肽结合的特征。结果表明，EGCG 不仅对 32 肽表现出高反应性，因为其结合似乎是熵驱动的，并且涉及两个连续的结合事件，每个事件都具有不同的结合强度。在相互作用过程中还检测到结构重排，这有助于形成的复合物更稳定。还使用 Caco-2 细胞系模型进行了体外跨上皮转运试验，结果表明 EGCG 能够显著降低基底外侧腔中游离肽的浓度。总之，这项研究提供了有关 EGCG 如何相互作用并可能调节一些生物活性 CD 肽功能的结构特征和分子机制的重要证据。
