曼氏迭宫绦虫四次跨膜蛋白(SmTSP)的生物信息学分析

Bioinformatics analysis of tetraspanin from Spirometra mansoni

目的:通过对曼氏迭宫绦虫的4次跨膜蛋白(SmTSP)潜在的生物学特征和参数进行分析,从而获得其具有的潜在生物学功能和应用价值。方法:利用美国国家生物技术信息中心(http://blast.ncbi.nlm.nih.gov/)和瑞士生物信息学研究所的蛋白分析专家系统(http://www.expasy.org/)提供的在线分析工具对编码蛋白的氨基酸序列的理化性质,跨膜结构和三维空间结构进行分析,同时利用Vector NTI suite和TreeView software生物信息分析软件进行编码氨基酸序列的相似性比对和进化树分析,利用CBS Prediction Servers BepiPred进行最大胞外环(LEL)的B细胞线性表位预测。结果:从文库中得到的SmTSP是全长基因,编码的蛋白是24.8kDa,理论等点为7.88,是一个稳定的蛋白分子。编码该蛋白的氨基酸序列共有4个跨膜区,分别是TM1aa16~38、TM2aa58~80、TM3aa87~109、TM4aa200~222。LEL中含有CCG结构、PXSC结构、GC结构和含有9个二聚体结合位点的保守特征结构。SmTSP全长序列与多房棘球绦虫、细粒棘球绦虫的相似性均能达到72%,但是与吸虫之间的相似性仅达到31%~59%,然而与人类相似性仅有23%,与小鼠的相似性最低,仅有17%。在进化树分析中,SmTSP与绦虫的亲源性在对比序列中是最近的,吸虫类次之,但是与埃及裂体吸虫和牛裂体吸虫、其他寄生虫(美洲钩虫和秀丽隐杆线虫)的亲源性相对较远,与哺乳动物亲源性最远。LEL有3个B细胞表位,分别是13aa^21aa、41aa^63aa和70aa^76aa。此外与人类四次跨膜蛋白的LEL中B细胞表位数量、分布的位置和编码的氨基酸都不同。结论:SmTSP可能是一个定位于虫体表膜并且具有应用前景的疫苗候选分子。

Objective： To analyze the potential biological characteristics and parameters of tetraspanin of Spirometra m ansotli （SmTSP）, its potential functions and vaccine development. Methods： Bioinformatics webstes such as NCBI （http：// blast, ncbi. nlm. nih. gov/） and ExPaSy （http：//www. expasy, org/） were used to predict its biochemical characteristics, trans-membrane helices and three-dimensional structure. To analyze the homology and phylogenetic tree, sequences of TSPs from various species were obtained from NCBI website and the results analyzed by software Vector NTI suit 8.0 and TreeView soft- ware. The linear B cell epitopes of large extracellular loop （LEL） of SmTSP were analyzed by CBS Prediction Servers BepiPred. Results： SmTSP was full-length gene, and its parameter of molecular weight and value of theoretical pI were 24.8 kDa and 7.88, respectively. It was a stably soluble molecule. SmTSP was composed of four transmembrane regions, TM1 aa16~38.TM2 aa58~80.TM3 aa87~109 and TM4 aa200~222, respectively. The LEL contained CCG domain, PXSC do- main, GC domain and four dimer interface binding sites. SmTSP was homologous to TSPs from Echinococcus multilocularis and Echinococcus granulocus with 72% identities. However, its homologous identities with TSPs of trematodes were from 31 % to 59%. Moreover, compared with TSPs from Homo sapiens and mouse, SmTSP showed lower identities, such as 23 and 17%, respectively. SmTSP closely clustered with the TSPs from the tapeworm genus and trematodes, but not with other species like Schistosoma haematobium , Schistosoma boris, Necator americanus , Caenorhabditis elegans , Drosophila ananas- sae and mammal animals. LEL contained three linear B cell epitopes, which were distinguishing with that from Homo sapiens in distribution positions and encoding amino acids. Oonclusion： SrnTSP might be a tegumental membrane protein and a poten- tial vaccine.