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流感杆菌可引起严重的人类感染性疾病,其中无荚膜流感杆菌或未分型流感杆菌(NTHI)是造成儿童中耳炎的主要病原体,并且尚无有效的预防菌苗.对两株中耳炎临床分离株NTHI33和NTHl12的htrA基因进行克隆和序列分析,发现其结构基因可编码产生一种46.4kDa蛋白,它与大肠杆菌和鼠伤寒杆菌的HtrA蛋白分别约有54%和69%的同源性.它作为一种应激反应蛋白,可通过高温诱导表达.该蛋白具有丝氨酸蛋白酶活性,通过对htrA基因定点诱变可去除此酶活性.将NTHI33的htrA基因重组到大肠杆菌BL21株中,可产生高水平的重组蛋白(rHtrA)和9种类似HtrA的突变体,后者仅一种具有蛋白酶活性.
Bacillus influenzae can cause serious human infectious diseases, of which non-capsaceae or non-type influenza bacillus (NTHI) is the main pathogen causing otitis media in children, and there is no effective preventive vaccine .Two strains of otitis media clinical isolates The htrA gene of NTHI33 and NTH12 was cloned and sequenced and found that its structural gene was encoded to produce a 46.4 kDa protein which was about 54% and 69% homologous to the HtrA protein of Escherichia coli and Salmonella typhimurium, respectively As a stress-response protein, it can be induced by high temperature, which has serine protease activity, which can be removed by site-directed mutagenesis of htrA gene.The recombination of htrA gene of NTHI33 into E. coli BL21 can produce high Level of recombinant protein (rHtrA) and nine HtrA-like mutants, the latter having only one protease activity.