新型冠状病毒E蛋白结构与免疫优势表位的信息学预测分析

The structure and immunodominant epitopes of SARS-CoV-2 E protein:an informatics prediction

目的:应用生物信息学方法预测和分析新型冠状病毒(SARS-CoV-2)包膜蛋白(E蛋白)的结构及免疫优势表位。方法:从NCBI GenBank数据库中检索SARS-CoV-2 E蛋白的氨基酸序列,通过Expas y服务器上的软件分析预测其理化性质、二级结构、跨膜区域;并结合其亲水性、表面可及性、极性、抗原性和柔韧性等综合分析,预测其可能的B细胞表位;利用Net CTL1.2 server预测CTL表位;通过Vector NTI对冠状病毒属E蛋白进行同源性分析;同时应用Swiss Model对E蛋白进行三维结构同源建模及功能结构域预测分析。结果:SARS-CoV-2 E蛋白由75个氨基酸残基组成,为跨膜蛋白,跨膜区域以α螺旋为主;E蛋白可能含有2个B细胞表位和6个CTL表位,其免疫优势表位区域分别位于其N端16-34aa和C端50-70aa区段;SARS-CoV-2与SARS-CoV和Bat-SARS-like-CoV E蛋白的免疫优势表位存在极高的同源性;其疏水性跨膜结构和PDZ结合基序分别位于N端12-34aa和C端72-75aa区段。结论:E蛋白为跨膜蛋白,其氨基酸序列的16-34和50-70区段可能为免疫优势表位。

Objective:To predict and analyze the structure and immunodominant epitope of envelope(E)protein of SARS-CoV-2 by bioinformatics.Methods:The amino acid sequence of SARS-CoV-2 E protein was retrieved from NCBI GenBank database,and its physicochemical properties,secondary structure and transmembrane region were predicted by software on EXPASY server.A comprehensive analysis of transmembrane domain,hydrophilicity profile,surface probability,polarity,antigenicity index and flexibility was further made to predict B-cell epitopes of E protein;NetCTL 1.2 server was used to predict the T-cell antigen epitopes;the homology of E protein of coronavirus was analyzed by Vector NTI;the 3-dimension structural homology and functional domain of the E protein was modeled by Swiss Model.Results:SARS-CoV-2 E protein was a transmembrane protein composed of 75 amino acid residues,and the transmembrane region was mainlyαhelix.The protein may contain two B-cell epitopes and six CTL epitopes and its immunodominant epitope were probably in the regions of 16-34,50-70 amino acids.SARS-CoV-2 E protein had high homology with SARS-CoV and Bat-SARS-like-CoV.The hydrophobic transmembrane domain and PDZ-binding motif were located in the N-terminal 12-34aa and Cterminal 72-75aa,respectively.Conclusion:E protein is a transmembrane domain protein,and the 16-34 and 50-70 amino acid regions of E protein are immunodominant epitopes,which provides a theoretical basis for the research on biological characteristics of SARS-CoV-2 E protein and vaccine.