Chen Y C, Delbrook K, Dealwis C, Mimms L, Mushahwar I K, Mandecki W
Molecular Biology Laboratory, Viral Discovery Group, Diagnostics Division, Abbott Laboratories, North Chicago, IL 60064-4000, USA.
Proc Natl Acad Sci U S A. 1996 Mar 5;93(5):1997-2001. doi: 10.1073/pnas.93.5.1997.
The structure of the small hepatitis B virus surface antigen (HBsAg) was investigated by epitope mapping of four anti-HBsAg monoclonal antibodies (mAbs). Amino acid sequences of epitopes were derived from affinity-enrichment experiments (biopanning) using a filamentous phage peptide library. The library consists of 10(9) different clones bearing a 30-residue peptide fused to gene III. Sequence homologies between peptides obtained from panning the library against the antibodies and the native HBsAg sequence allowed for precise description of the binding regions. Three of four mAbs were found to bind to distinct discontinuous epitopes between amino acid residues 101 and 207 of HBsAg. The fourth mAb was demonstrated to bind to residues 121-124. The sequence data are supported by ELISA assays demonstrating the binding of the HBsAg-specific peptides on filamentous phage to mAbs. The sequence data were used to map the surface of HBsAg and to derive a topological model for the alpha-carbon trace of the 101-207 region of HBsAg. The approach should be useful for other proteins for which the crystal structure is not available but a representative set of mAbs can be obtained.
通过对四种抗乙肝表面抗原（HBsAg）单克隆抗体（mAb）进行表位作图，研究了小分子乙肝病毒表面抗原（HBsAg）的结构。表位的氨基酸序列来自使用丝状噬菌体肽库进行的亲和富集实验（生物淘选）。该文库由10⁹个不同的克隆组成，每个克隆带有一个与基因III融合的30个残基的肽。通过将文库与抗体进行淘选获得的肽与天然HBsAg序列之间的序列同源性，使得能够精确描述结合区域。发现四种mAb中的三种与HBsAg氨基酸残基101至207之间不同的不连续表位结合。第四种mAb被证明与残基121 - 124结合。ELISA分析证实丝状噬菌体上的HBsAg特异性肽与mAb结合，从而支持了序列数据。这些序列数据用于绘制HBsAg的表面图谱，并推导HBsAg 101 - 207区域α-碳轨迹的拓扑模型。该方法对于那些无法获得晶体结构但可以获得一组代表性mAb的其他蛋白质应该是有用的。
