Studies on molecular organization, immunochemical characterization and biological activities of protein layers in bacterial surfaces

我们研究了一些梭状芽孢杆菌和乳杆菌外层有规则排列的蛋白(RA蛋白)的分子组成、免疫化学性质和生物活性。1)电子显微镜显示艰难梭菌的细胞壁有一个由近乎正方形排列组成的外层，并含有两种主要蛋白质，根据菌株的不同，MRS分别为32和45 kDa或38和42 kDa。这两种RA蛋白的氨基酸组成和肽谱各不相同。Ca~(2+)~(2+)是尿素或盐酸胍增溶的两种RA蛋白重组规则阵列所必需的。32 kDa蛋白具有与HeLa细胞的黏附活性，而45 kDa蛋白不具有黏附活性。免疫电子显微镜显示两种RA蛋白均存在于细胞表面。2)肉毒梭菌E型外细胞壁上有一个线状排列的细小排列，由三种主要蛋白质组成，其MRS分别为90、60和25 kDa。纯化了90 kDa和60 kDa蛋白，并对其进行了免疫化学鉴定。免疫电子显微镜显示两种蛋白均定位于细胞壁表面。3)只有一组嗜酸乳杆菌的菌株有规则的排列，而其他组没有。根据多肽图谱和RA蛋白的免疫印迹，A组可进一步分为4个或4个以上亚组。

We have investigated the molecular organization, immunochemical properties, and biological activities of the regularly arranged proteins (RA proteins) in the outer cell well layers of some clostridia and lactobacilli. 1) The cell wall of clostridium difficile was revealed by electron microscopy to have an outer layer composed of a nearly square array and contained the two major proteins with Mrs of 32 and 45 kDa, or 38 and 42 kDa, depending on the strains. The amino acid composition and peptide maps of the two RA proteins differed from each other. Ca^<2+> was essential for the reassembly of regular array from the two RA proteins solubilized with urea or guanidine hydrochloride. The 32 kDa protein possessed the adhesive activity ot HeLa cells, whereas the 45 kDa protein did not. Immunoelectron microscopy revealed that the two RA proteins existed on the cell well surface. 2) A linearly arranged thin array was observed on the outer cell wall layer of Clostridium botulinum type E and composed of three major proteins with Mrs of 90, 60 and 25 kDa. The 90 and 60 kDa proteins were purified and immunochemically characterized. Both proteins were shown to locate on the wall surface by immunoelectron microscopy. 3) Regular arrays were present in only strains belonging to a group of lactobacillus acidophilus but not in the other groups. Based on the peptide mapping and immunoblotting of the RA proteins, the A group could be further classified into 4 or more subgroups.