金黄色葡萄球菌肠毒素A蛋白的B细胞表位的预测

目的预测金黄色葡萄球菌肠毒素A蛋白（SEA）的B细胞表位。方法以金黄色葡萄球菌合肥乳源分离株M3基因组DNA为模板，PCR扩增SEA基因并进行序列测定与分析。应用DNAstar protean软件对SEA蛋白的二级结构、柔性、亲水性、表面可能性和抗原指数等多参数进行综合分析，预测其B细胞表位。结果M3分离株的SEA基因全长774bp，编码由257个氨基酸组成的相对分子量为29．67kDa的SEA蛋白，M3分离株SEA基因与标准株的核苷酸序列与氨基酸序列同源性分别为98．7％和98．4％。SEA蛋白的优势B细胞表位位于肽链的第64—68、100～107、138—141、156—160、166～173、213～217和237～244区段。结论预测出SEA蛋白的7个优势B细胞表位，为进而克隆表达表位蛋白，制备针对SEA表位的单克隆抗体奠定了基础。

Prediction of the B-cell epitopes for staphylococcus enterotoxin A protein

Objective To predict the B-cell epitopes of staphylococcus enterotoxin A(SEA) protein.Method The genomic DNA of Staphylococcus aureus M3 strain isolated from raw milk from Hefei was used as the template for polymerase chain reaction(PCR) to amplify the SEA gene,then the SEA gene was sequenced and analysed.In order to predict the B-Cell epitopes of SEA protein,several parameters such as secondary structure,flexibility,hydrophilicity,accessibility and antigenicity of SEA amino acid sequence were comprehensively analysed by the DNAstar Protean software.Result The full length of SEA gene from M3 strain contained a 774 bp open reading frame,encoding 257 amino acid residues with relative molecular mass of 29.67 kDa.The homology of nucleotide sequence and amino acid sequence of SEA gene between M3 strain and the standard strain was 98.7% and 98.4% respectively.The predicted most possible epitopes on SEA were located within or nearby its N-terminal Nos.64-68,100-107,138-141,156-160,166-173,213-217 and 237-244.Conclusion Seven dominant B-cell epitopes had been predicted,which will be helpful for cloning and expressing the epitope proteins and producing the monoclonal antibody against the epitopes.