日本血吸虫MBLAC1基因的克隆及生物信息学分析

目的 克隆日本血吸虫金属β内酰胺酶结构域蛋白1(Metallo-beta-lactamases domain-containing protein 1,MBLAC1)基因,并研究其编码蛋白的生物学特性。方法 以成虫虫体cDNA为模板,利用PCR技术扩增SjMBLAC1基因,并通过生物信息学技术分析该基因编码蛋白的结构特征。结果 SjMBLAC1扩增基因片段大小为711 bp,编码236个氨基酸,预测蛋白质分子量约为26 kD,理论等电点为4.84。该蛋白的第7~222位氨基酸为保守结构域,属于MBL超级家族;不存在跨膜结构域及信号肽;具有一个N-糖基化位点,在第186位氨基酸;二级结构中包含α-螺旋8.90%、β-折叠27.97%、无规则卷曲区域63.14%,推测SjMBLAC1蛋白具有9个优势B细胞抗原表位。结论 成功克隆了SjMBLAC1基因并对其编码蛋白进行了生物信息学分析,从而为开展该蛋白的生物学功能研究及筛选抗血吸虫病疫苗候选分子提供了基础。

Molecular cloning and bioinformatics analysis on MBLAC1 of Schistosoma japonicum

In order to clone the gene of metallo-beta-lactamases domain-containing protein 1 from Schistosoma japonicum (SjMBLAC1), and analyze the biological characteristics of the coding protein, the SjMBLAC1 gene was amplified by the polymerase chain reaction (PCR) technique with adult worm cDNA as a template,and the structural features of the coding protein were analyzed by the bioinformatics technique. Results showed that the full-length of SjMBLAC1 gene was 711 bp and it encoded a protein of 236 amino acids with a predicted molecular weight of 26 kDa and an isoelectric point of 4.84. It contained a conserved domain from the 7th to the 222nd amino acids which belonged to the MBL super family, and an N-glycosylation site at the 186th amino acid without the signal peptide and the transmembrane domain. In addition, its secondary structures comprised 8.90% α-helices, 27.97% β-sheets, and 63.14% random coils. At last, it was speculated that the SjMBLAC1 protein had 9 dominant B cell antigen epitopes. It is concluded that SjMBLAC1 was successfully cloned and analyzed by the bioinformatics technique. This study will provide the foundation for proceeding further research on the biological function of SjMBLAC1 and permit the screening new vaccine candidates against schistosomiasis.