Keck P C, Huston J S
Creative BioMolecules, Hopkinton, Massachusetts 01748, USA.
Biophys J. 1996 Oct;71(4):2002-11. doi: 10.1016/S0006-3495(96)79398-0.
Molecular modeling studies on antibody Fv regions have been pursued to design a second antigen-binding site (chi-site) in a chimeric single-chain Fv (chi sFv) species of about 30 kDa. This analysis has uncovered an architectural basis common to many Fv regions that permits grafting a chi-site onto the Fv surface that diametrically opposes the normal combining site. By using molecular graphics analysis, chimeric complementarity-determining regions (chi CDRs) were defined that comprised most of the CDRs from an antibody binding site of interest. The chain directionality of chi CDRs was consistent with that of specific bottom loops of the sFv, which allowed for grafting of chi CDRs with an overall geometry approximating CDRs in the parent combining site. Analysis of 10 different Fv crystal structures indicates that the positions for inserting chi CDRs are very highly conserved, as are the corresponding chi CDR boundaries in the parent binding site. The results of this investigation suggest that it should be possible to generally apply this approach to the development of chimeric bispecific antibody binding site (chi BABS) proteins.
针对抗体Fv区域开展了分子建模研究，旨在设计一种约30 kDa的嵌合单链Fv（chi sFv）中的第二个抗原结合位点（chi位点）。该分析揭示了许多Fv区域共有的结构基础，这使得能够将chi位点嫁接到与正常结合位点完全相对的Fv表面。通过分子图形分析，定义了嵌合互补决定区（chi CDRs），其包含来自感兴趣抗体结合位点的大部分CDRs。chi CDRs的链方向性与sFv特定底部环的链方向性一致，这使得能够以总体几何形状近似亲本结合位点中CDRs的方式嫁接chi CDRs。对10种不同Fv晶体结构的分析表明，插入chi CDRs的位置以及亲本结合位点中相应的chi CDR边界高度保守。这项研究结果表明，一般来说，有可能将这种方法应用于嵌合双特异性抗体结合位点（chi BABS）蛋白的开发。
