利用二维核磁方法对乙肝病毒表面抗原Pre S1N端 2 0～ 47肽段进行溶液构象研究 ,并用距离几何方法搭建分子结构 ,最后用分子动力学模拟方法对结构进行优化 .分析结果发现该肽段存在 4个 β turn ,位置与免疫学定义的抗原抗体结合位点相符 . The two-dimensional nuclear magnetic resonance method was used to study the conformation of the 20 ~ 47 peptide of Pre S1N of hepatitis B virus surface antigen, and the molecular structure was constructed by distance geometry method. Finally, the structure was optimized by molecular dynamics simulation. There are 4 beta turns, located in line with immunologically defined antigen-antibody binding sites.