田鼠巴贝虫GAPDH蛋白特性和抗原表位的生物信息学分析

Bioinformatics analysis of the main characteristics and epitopes of the gene encoding glyceraldehyde - 3 - phosphate dehydrogenase from Babesia microti

目的分析田鼠巴贝虫3-磷酸甘油醛脱氢酶（BmGAPDH）的蛋白特性和抗原表位。方法运用ORFFinder、PROSITE、ProtParam、SignaIP、TMHMMServer、SOUSI、MotifScan、Bcepred、HNN等生物信息学软件分析预测BmGAPDH基因的开放阅读框和编码蛋白的特征结构域、理化性质、信号肽、跨膜结构域、稳定性、可溶性、翻译后修饰位点、亲水性、柔韧性、表面可及性、二级结构等特性；同时结合DNAStar和SWISS—MODEL软件分别预测蛋白的抗原表位和三维空间结构。结果BmGAPDH由1074个核苷酸编码的357个氨基酸组成，其特征结构域位于170—177位氨基酸残基。编码蛋白相对分子质量为3．833309×10^4，分子式为C1700H2723N457O514S17理论等电点为6．98，不存在信号肽，有1个跨膜区，23个翻译后修饰位点，6个亲水性参数得分≥1．9的区域，3个柔韧性参数得分≥2．0的区域，10个表面可及性参数得分≥1．9的区域，8个潜在的B细胞抗原表位，19个潜在的T细胞抗原表位，在溶液中性质稳定，且为疏水性蛋白。BmGAPDH蛋白和人类的GAPDH蛋白序列覆盖率为56％，相似性为70％。结论BmGAPDH含有多种抗原表位，且含量丰富，具有成为巴贝虫病疫苗候选抗原的潜在特性。

Objective To analyze the main characteristics and epitopes of the gene encoding GAPDH protein from Babesia microti （BmGAPDH）. Methods The open reading frame, physic - chemical properties, signal peptide, cross membrane area, solubility, post - translational modification site, hydrophilicity, surface accessibility, flexibility, second- ary structure and antigenic epitope of BmGAPDH protein were analyzed and predicted using bioinformatics analysis pro- grams including ORF Finder, PROSITE, ProtParam, SignalP, TMHMM Server, SOSUI, MotitScan, Bcepred, HNN as well as DNAStar Protean. In addition, three dimensional structure of the protein was predicted by DNAStar and SWISS - MODEL. Results BmGAPDH is consisted of 357 amino acids encoded by 1 074 nucleotides. Its signature motif is loca- ted at 170 - 177 amino acids. Its molecular mass is 3. 833 309× 104, with a molecular formula of C1700H2723N457O514S17 , and a theoretical isoelectric point of 6.98. Furthermore, there are 6 zones with ≥1. 9 hydrophilicity, 3 zones with t〉 2.0 flexibility, and 10 zones with≥ 1.9 surface accessibility in BmGAPDH. Moreover, There are 8 zones with potential B cell antigenic epitopes, 19 zones with potential T cell antigenic epitopes, and 23 post - translational modification sites. The sequences of BmGAPDH and homo sapiens GAPDH protein have a query cover of 56% and identity of 70%. Con- clusions BmGAPDH protein has multiple antigenic epitopes, which can be used as a potential vaccine candidate for babesiosis.