番鸭呼肠孤病毒σC蛋白模拟抗原表位的研究

Screening mimic epitope of muscovy duck reovirus σC protein with phage-displayed peptide library

以番鸭呼肠孤病毒MW9710分离株原核表达蛋白pGEX-4T-1-σC为靶分子,利用噬菌体随机七肽库进行亲和筛选,经过4轮亲和筛选后,对整个被选噬菌体集合单链DNA进行测序。结果:噬菌体展示序列为CATCCTATTCATCCGCGTCAT,相应的短肽序列为HPFYSCY,该短肽序列与MDRVσC氨基酸序列N端一处-P-YS--的氨基酸片段相似,推论MDRVσC的模拟抗原表位可能是由该不连续氨基酸片段所构成的构象表位。通过Genbank的蛋白质检索,发现该构象表位也存在于前B细胞克隆增强因子的多肽序列中。结果表明,噬菌体展示随机肽库技术是一种用于研究抗原表位结构的有效方法。

The prokaryotic expression protein（pGEX-4T-1-σC）of Muscovy duck reovirus （MDRV） MW9710 strain was targeted for the screening by using a random bacteriophage 7-mers peptide library. Sequence of the single strand DNA of the phage-displayed peptide was determined and analyzed after four rounds of screening. The results showed that the DNA sequence of the positive peptide was CATCCTATTCATCCGCGTCAT,the corresponding peptide sequence was HPFYSCY,and the positive peptide was similar to a fragment,-P-YS--,located on N-terminal of MDRV-σC. It was thus postulated that the mimic antigen epitope of MDRV-σC was a conformational epitope with a discontinuous amino acid fragment. From the Genbank,this conformational epitope was also found in the peptide sequence of Pre-B cell colony-enhancing factor （PBEF）.It appeared that using the phage-displayed peptide library to analyze structure of antigen epitopes could be a useful means.The results obtained from this study provided valuable information for our further study of the conformation and function of the MDRV proteins.