细粒棘球绦虫延伸因子1生物信息学分析

Property and structure of elongation factor 1 in Echinococcus granulous,a bioinformatics analysis

目的利用生物信息学技术对细粒棘球绦虫的延伸因子1(EF-1)进行分析,探讨其诊断价值。方法通过Expasy系统预测EF-1的理化性质,使用DNAStar软件分析蛋白亲水性、柔性区域、抗原指数及表面可及性,利用ABCpred与IEDB软件综合预测B细胞线性抗原表位,通过DNAStar软件预测T细胞表位,使用SOPMA软件预测二级结构,SWISS-MODEL网站构建EF-1的三级结构,使用MEGA软件选择neighbor joining法构建EF-1氨基酸序列的系统发育树。结果 EF-1基因序列全长1 412 bp,含有2个内含子;EF-1亲水性得分较高的区域为35~45、52~70、126~140、158~183、301~322、357~380、424~448;柔性区域为26~45、54~71、162~176、300~318、357~381、432~448;抗原性指数得分较高的区域分布与柔性区域一致;表面可及性得分较高的区域较少,主要分布在39~54、62~76、128~132、161~170、220~234、315~329、354~372、424~448;可能的B细胞线性表位的氨基酸序列为120~130、286~295、306~320、365~378;可能的优势性T细胞表位区域为34~48、164~177、222~244、280~290、321~330、396~407;EF-1的二级结构中α螺旋占32.81%、β折叠占22.54%、β转角占10.94%、无规则卷曲占33.71%;系统发育树结果表明多房棘球绦虫为一枝,其余聚于一枝,且内部形成许多梳齿状分枝。结论得到4个可能形成B细胞表位的区域、6个优势性T细胞表位区域,EF-1具有较高的保守性,可作为免疫诊断和药物治疗靶点。

Objective To analyze the property and structure of elongation factor 1 （ EF-1 ） in Echinococcus granu- lous with bioinformatics technology and to explore its value in diagnosis of echinococcosis. Methods Physicochemical property of EF-1 was predicted using Expasy system. Hydrophiloity plot, flexible regions, antigenic index, and surface ac- cessibility were analyzed with DNAStar software. B cell linear antigen epitopes were forecasted with ABCpred and IEDB software. T cell antigen epitopes were forecasted with DNAStar software. The secondary and three-dimensional structure of EF-1 were determined using SOPMA software and SWISS-MODEL website separately. The phylogenetic tree for amino acid sequences of EF-1 was built with neighbor joining method of MEGA software. Results The whole gene of EF-1 was 1 412 bp in length,containing two introns. The high score areas of hydrophiloity plot were 35 -45,52 -70,126 - 140,158 - 183,301 - 322,357 - 380, and 424 - 448. The flexible regions were 26 - 45,54 - 71,162 - 176,300 - 318,357 -381 ,and 432 -448. The regions with high score of antigenic index were similar to the flexible regions. There were a few regions with the high score of surface accessibility ,mainly locating at 39 - 54,62 - 76,128 - 132,161 - 170,220 - 234,315 -329,354 -372 ,and 424 -448. The potential amino acids sequences of B cell linear epitopes were 120 -130, 286 -295,306- 320, and 365 -378. The potential advantaged T cell epitope areas were 34 -48,164 -177,222 -244, 280 -290,321 -330, and 396 -407. The proportions of secondary structure of EF-1 were 32. 81% for ix-helix,22. 54% for t-sheet, accounted 10. 94% for [3-comer, and 33.71% for random coil, respectively. The constructed phylogenetic tree of EF-1 demonstrates a branch of Echinococcus multilocularis had its own branch and another branch with many internal dentate branches. Conclusion Four B cell epitopes and six advanted T cell epiopes of EF-1 were identified with the bioinformatics analysis and phylogenetic tree reveals that EF-1 is high conservative. These findings suggest that the epitopes of EF-1 in Echinococcus granulous could be adopted as targets for immunological diagnosis and drug treatment of echinococcosis.