Purification and characterization of a Bacteroides loeschei adhesin that interacts with procaryotic and eucaryotic cells

The adhesin of Bacteroides loeschei PK1295 that mediates coaggregation with Streptococcus sanguis 34 and hemagglutination of erythrocytes was purified to electrophoretic homogeneity. The lectinlike protein has an estimated native Mr of 450,000 and consists of six subunits of identical molecular weight (Mr 75,000). The purified adhesin appears to be a basic protein with a pI between 7.4 and 8.0. Amino acid and N-terminal sequence analyses were carried out with the purified protein. These indicated that the protein contains a large number of Asx and Glx residues as well as basic amino acid residues. The binding site of the pure adhesin retained its native configuration during purification. When preincubated with streptococcal partner cells at pH 4.6, the adhesin prevented B. loeschei cells from coaggregating with the streptococci. An adhesin preparation adjusted to a pH of 6.8 rapidly agglutinated both streptococci and neuraminidase-treated erythrocytes. Galactosides inhibited the agglutination reactions.

洛氏杆菌PK1295的粘附蛋白介导了与链球菌34的凝聚，红细胞的凝血蛋白被纯化为电泳同质性。分线性蛋白的估计天然MR为450,000，由六个相同分子量的亚基组成（MR 75,000）。纯化的粘附素似乎是一种基本蛋白，PI在7.4和8.0之间。用纯化的蛋白质进行氨基酸和N末端序列分析。这些表明该蛋白质包含大量的ASX和GLX残基以及碱性氨基酸残基。纯粘附素的结合位点在纯化过程中保留了其天然构型。当在pH 4.6处与链球菌伴侣细胞预孵育时，粘附素可以防止叶氏芽孢杆菌与链球菌凝聚。粘附蛋白的制剂调节至6.8迅速凝集的链球菌和神经氨酸酶处理的红细胞。半乳糖苷抑制了凝集反应。