宁夏人细粒棘球蚴延伸因子-1重组蛋白特性分析及抗原表位预测

Property Analysis and Antigen Epitope Prediction of Eg.EF-1 from Human in Ningxia

目的分析宁夏人Eg.EF-1重组蛋白的氨基酸序列,了解该蛋白的特性,预测其抗原表位,为进一步研究多肽疫苗提供理论依据。方法克隆Eg.EF-1基因片段并测序,重组入Eg.EF-1/pGEX-6P-1载体表达重组蛋白Eg.EF-1并鉴定其免疫学活性,利用生物信息学方法推测Eg.EF-1重组蛋白质的氨基酸序列、分析Eg.EF-1重组蛋白特性及二级结构、在线预测重组蛋白三维图象数据并将其结果用Anthe_5_0和spdbv37sp5软件模拟该蛋白三维结构,对Eg.EF-1重组蛋白氨基酸序列进行BLAST同源性比对分析,用DNAStar/Protean、BIOSUN软件和HLALigand/Motif网上B细胞抗原表位预测数据库对蛋白抗原表位进行预测。结果Eg.EF-1基因开放阅读框编码一个由230个氨基酸残基组成的多肽,同源性分析发现,重组蛋白氨基酸序列与数据库中收录的意大利细粒棘球蚴延伸因子EF-1的氨基酸序列有98%的同源性;蛋白特性分析显示Eg.EF-1重组蛋白是疏水性极强的酸性蛋白,含有较多的α螺旋结构;3种软件综合分析结果预测,Eg.EF-1基因重组蛋白抗原表位位置为20～26(SATEQKG)、50～56(SWNERME)、176～185(LWGTSKLVPL)、199～205(VENDKVG)、217～229(ELEDYVQSVDVAS)5个氨基酸肽段。结论Eg.EF-1重组蛋白可能是人细粒棘球蚴延伸因子-1相关蛋白,根据3种生物信息学工具预测的抗原表位是研究多肽疫苗时合成肽段的参考依据。

OBJECTIVE To analyze the property of recombinant protein Eg. EF-1 from clone Eg. EF-1 gene, and predict its antigen epitopes. METHODS After sequencing the cloned Eg. EF-1 gene, its recombined protein Eg. EF-1 was expressed, then its property and 3D construction was deduced by the tool of Anthe 5.0 and spdbv37sp5. Its amino acid sequence homology was compaired by NCBI/BLAST, and its epitopes was predicted by DNAStar/Protean, BIOSUN and HLA Ligand/Motif software with bioinformatics on line. RESULTS The open reading frame （ORF） of Eg. EF-1 coding a peptide consisted of 230 amino acid and 98% of them coincidenced with the EF-1 from Italian sheep in GeneBank; the recombinant protein Eg. EF-1 was acid with α-helix, the predicted epitopes by three softwares located on five peptides were 20 - 26 （ SATEQKG）, 50 - 56 （ SWNERME）, 176 -185 （ LWGTSKLVPL）, 199 - 205 （VENDKVG）, 217 -229（ELEDYVQSVDVAS）. CONCLUSION Recombinant protein Eg. EF-1 is related protein of the human Eg. EF-1. The epitopes predicted by three biolnformatics tool provided a base for peptide synthesis as hydatid polypeptide vaccine.