Facultad de Ciencias Exactas y Naturales, Departamento de Química Biológica, Universidad de Buenos Aires, Cdad. Universitaria, Pabellón II, 4 piso, Lab QB40, C1428EGA, CABA, Buenos Aires, Argentina.
Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), CONICET-Universidad de Buenos Aires, Buenos Aires, Argentina.
Appl Microbiol Biotechnol. 2019 Jun;103(12):4839-4857. doi: 10.1007/s00253-019-09795-y. Epub 2019 May 3.
The surface layer (S-layer) protein of Lactobacillus acidophilus is a crystalline array of self-assembling, proteinaceous subunits non-covalently bound to the outmost bacterial cell wall envelope and is involved in the adherence of bacteria to host cells. We have previously described that the S-layer protein of L. acidophilus possesses anti-viral and anti-bacterial properties. In this work, we extracted and purified S-layer proteins from L. acidophilus ATCC 4356 cells to study their interaction with cell wall components from prokaryotic (i.e., peptidoglycan and lipoteichoic acids) and eukaryotic origin (i.e., mucin and chitin), as well as with viruses, bacteria, yeast, and blood cells. Using chimeric S-layer fused to green fluorescent protein (GFP) from different parts of the protein, we analyzed their binding capacity. Our results show that the C-terminal part of the S-layer protein presents lectin-like activity, interacting with different glycoepitopes. We further demonstrate that lipoteichoic acid (LTA) serves as an anchor for the S-layer protein. Finally, a structure for the C-terminal part of S-layer and possible binding sites were predicted by a homology-based model.
嗜酸乳杆菌的表面层 (S-layer) 蛋白是由自我组装的、非共价结合到最外层细菌细胞壁包膜的蛋白质亚基组成的结晶阵列，参与细菌与宿主细胞的黏附。我们之前曾描述过嗜酸乳杆菌的 S 层蛋白具有抗病毒和抗细菌的特性。在这项工作中，我们从嗜酸乳杆菌 ATCC 4356 细胞中提取和纯化了 S 层蛋白，以研究它们与来自原核（即肽聚糖和脂磷壁酸）和真核（即粘蛋白和几丁质）的细胞壁成分以及与病毒、细菌、酵母和血细胞的相互作用。使用融合到不同部位 GFP 的嵌合 S 层蛋白，我们分析了它们的结合能力。我们的结果表明，S 层蛋白的 C 末端部分具有凝集素样活性，与不同的糖基表位相互作用。我们进一步证明，脂磷壁酸 (LTA) 是 S 层蛋白的锚定部位。最后，通过基于同源性的模型预测了 S 层 C 末端部分的结构和可能的结合位点。
