Faculty of Chemistry, Biotechnology and Food Science, NMBU - Norwegian University of Life Sciences, Ås, Norway.
Sci Rep. 2020 Jun 15;10(1):9640. doi: 10.1038/s41598-020-66531-7.
Members of the genus Lactobacillus have a long history in food applications and are considered as promising and safe hosts for delivery of medically interesting proteins. We have assessed multiple surface anchors derived from Lactobacillus plantarum for protein surface display in multiple Lactobacillus species, using a Mycobacterium tuberculosis hybrid antigen as test protein. The anchors tested were a lipoprotein anchor and two cell wall anchors, one non-covalent (LysM domain) and one covalent (sortase-based anchoring using the LPXTG motif). Thus, three different expression vectors for surface-anchoring were tested in eight Lactobacillus species. When using the LPXTG and LysM cell wall anchors, surface display, as assessed by flow cytometry and fluorescence microscopy, was observed in all species except Lactobacillus acidophilus. Use of the cell membrane anchor revealed more variation in the apparent degree of surface-exposure among the various lactobacilli. Overproduction of the secreted and anchored antigen impaired bacterial growth rate to extents that varied among the lactobacilli and were dependent on the type of anchor. Overall, these results show that surface anchors derived from L. plantarum are promising candidates for efficient anchoring of medically interesting proteins in other food grade Lactobacillus species.
乳杆菌属的成员在食品应用中有着悠久的历史，被认为是具有前景和安全的宿主，可用于输送具有医学意义的蛋白质。我们评估了源自植物乳杆菌的多种表面锚定蛋白，用于多种乳杆菌属物种的蛋白质表面展示，使用结核分枝杆菌杂交抗原作为测试蛋白。测试的锚定蛋白包括脂蛋白锚定蛋白和两种细胞壁锚定蛋白，一种是非共价的（LysM 结构域），另一种是共价的（基于 LPXTG 基序的 Sortase 锚定）。因此，在八种乳杆菌属物种中测试了三种不同的表面锚定表达载体。当使用 LPXTG 和 LysM 细胞壁锚定蛋白时，除嗜酸乳杆菌外，所有物种均通过流式细胞术和荧光显微镜观察到表面展示。使用细胞膜锚定蛋白显示出各种乳杆菌之间表面暴露程度的明显差异。分泌型和锚定型抗原的过度生产会以乳杆菌之间存在差异的程度影响细菌的生长速度，并且取决于锚定类型。总体而言，这些结果表明，源自植物乳杆菌的表面锚定蛋白是在其他食品级乳杆菌属物种中有效锚定具有医学意义的蛋白质的有前途的候选者。
