Lu D, Boyd B, Lingwood C A
Department of Medical Genetics, University of Toronto, Ontario, Canada.
FEMS Microbiol Lett. 1998 Aug 1;165(1):129-37. doi: 10.1111/j.1574-6968.1998.tb13137.x.
In the H. influenzae type b (Hib) genome, two putative adhesin B genes, HI0119 and HI0362, have been identified on the basis of homology to the adhesin B (FimA) of Streptococcus parasanguis. We expressed and characterized one of them, HI0119, from a non-typeable H. influenzae strain (NTHI). This 37 kDa protein was selectively isolated from an H. influenzae surface protein (water) extract by elution from a celite matrix with EDTA. The adhesin B protein is 97.7% identical to that of H. influenzae, strain Rd, has 23.7% identity and 47.8% similarity to FimA of Streptococcus parasanguis but is distinguished from the FimA family by the absence of the N-terminal lipid anchor consensus sequence LXXC, the presence of a C-terminal disulfide-bonded domain, and a central histidine-rich domain. Recombinant fusion protein bound specifically to celite. Antisera raised against fusion protein recognized a 37 kDa protein from whole cell extracts of H. influenzae on Western blots. A truncated mutant lacking the C-terminal disulfide-bonded domain and a Cys308 to Ser mutant were constructed and expressed as fusion proteins. Both mutants retained celite binding. However, purified fusion proteins could not, unlike H. influenzae, bind Hep2 cells, suggesting that HI0119 may not be an adhesin in this organism.
在b型流感嗜血杆菌（Hib）基因组中，基于与副血链球菌粘附素B（FimA）的同源性，已鉴定出两个假定的粘附素B基因HI0119和HI0362。我们从一株不可分型流感嗜血杆菌（NTHI）中表达并鉴定了其中一个基因HI0119。通过用EDTA从硅藻土基质上洗脱，从流感嗜血杆菌表面蛋白（水）提取物中选择性分离出这种37 kDa的蛋白质。该粘附素B蛋白与流感嗜血杆菌Rd株的蛋白有97.7%的同一性，与副血链球菌的FimA有23.7%的同一性和47.8%的相似性，但与FimA家族的区别在于缺乏N端脂质锚定共有序列LXXC，存在C端二硫键结合结构域和中央富含组氨酸的结构域。重组融合蛋白与硅藻土特异性结合。针对融合蛋白产生的抗血清在Western印迹中识别出流感嗜血杆菌全细胞提取物中的一种37 kDa蛋白。构建了一个缺乏C端二硫键结合结构域的截短突变体和一个Cys308突变为Ser的突变体，并将其表达为融合蛋白。两个突变体都保留了与硅藻土的结合能力。然而，与流感嗜血杆菌不同，纯化的融合蛋白不能结合Hep2细胞，这表明HI0119在该生物体中可能不是一种粘附素。
