Adhesion properties of Lactobacillus rhamnosus mucus-binding factor to mucin and extracellular matrix proteins

We previously described potential probiotic Lactobacillus rhamnosus strains, isolated from fermented mare milk produced in Sumbawa Island, Indonesia, which showed high adhesion to porcine colonic mucin (PCM) and extracellular matrix (ECM) proteins. Recently, mucus-binding factor (MBF) was found in the GG strain of L. rhamnosus as a mucin-binding protein. In this study, we assessed the ability of recombinant MBF protein from the FSMM22 strain, one of the isolates of L. rhamnosus from fermented Sumbawa mare milk, to adhere to PCM and ECM proteins by overlay dot blot and Biacore assays. MBF bound to PCM, laminin, collagen IV, and fibronectin with submicromolar dissociation constants. Adhesion of the FSMM22 mbf mutant strain to PCM and ECM proteins was significantly less than that of the wild-type strain. Collectively, these results suggested that MBF contribute to L. rhamnosus host colonization via mucin and ECM protein binding.我们此前曾报道过从印度尼西亚松巴哇岛发酵马乳中分离得到的潜在益生菌鼠李糖乳杆菌（Lactobacillus rhamnosus）菌株，此类菌株对猪结肠黏蛋白（PCM）与细胞外基质（ECM）蛋白具有较高黏附能力。近期研究在鼠李糖乳杆菌GG菌株中发现黏液结合因子（MBF）作为黏蛋白结合蛋白。本研究通过覆盖式斑点杂交法与Biacore检测实验，评估了从松巴哇岛发酵马乳中分离得到的鼠李糖乳杆菌菌株FSMM22的重组MBF蛋白对PCM及ECM蛋白的黏附能力。结果显示，MBF可与PCM、层粘连蛋白、Ⅳ型胶原及纤连蛋白结合，其解离常数处于亚微摩尔级别。FSMM22的mbf突变菌株对PCM及ECM蛋白的黏附能力显著低于野生型菌株。综上，本研究结果表明MBF可通过介导黏蛋白与ECM蛋白结合，助力鼠李糖乳杆菌完成宿主定殖。