Aix Marseille University, CNRS, Centrale Marseille, ISM2, IM2B, 13007 Marseille, France.
Laboratoire de Biologie Moléculaire et Cellulaire, Université des Frères Mentouri Constantine 1, RN79 Constantine, Algeria.
Biomolecules. 2021 Oct 31;11(11):1613. doi: 10.3390/biom11111613.
Adhesion to the digestive mucosa is considered a key factor for bacterial persistence within the gut. In this study, we show that E1 can express the gene, which encodes an adhesin of the MSCRAMMs family, only when it colonizes the gut. The RadA N-terminal region contains an all-β bacterial Ig-like domain known to interact with collagens. We observed that it preferentially binds human immunoglobulins (IgA and IgG) and intestinal mucins. Using deglycosylated substrates, we also showed that the RadA N-terminal region recognizes two different types of motifs, the protein backbone of human IgG and the glycan structure of mucins. Finally, competition assays with lectins and free monosaccharides identified Galactose and N-Acetyl-Galactosamine motifs as specific targets for the binding of RadA to mucins and the surface of human epithelial cells.
黏附于消化道黏膜被认为是细菌在肠道内持续存在的关键因素。在本研究中，我们发现当 E1 定植于肠道时，它可以表达编码黏附素（属于 MSCRAMM 家族）的 基因。RadA N 端区域含有一个全β细菌 Ig 样结构域，已知该结构域与胶原蛋白相互作用。我们观察到它优先结合人免疫球蛋白（IgA 和 IgG）和肠道粘蛋白。使用去糖基化的底物，我们还表明 RadA N 端区域识别两种不同类型的基序，即人 IgG 的蛋白质骨架和粘蛋白的聚糖结构。最后，通过凝集素和游离单糖的竞争实验，确定半乳糖和 N-乙酰半乳糖胺基序是 RadA 与粘蛋白和人上皮细胞表面结合的特定靶标。
