Ban N, Escobar C, Hasel K W, Day J, Greenwood A, McPherson A
Department of Biochemistry, University of California, Riverside 92521.
FASEB J. 1995 Jan;9(1):107-14. doi: 10.1096/fasebj.9.1.7821749.
The crystal structure of anti-idiotopic Fab 409.5.3, made against an E2 specific feline infectious peritonitis virus-neutralizing antibody 730.1.4, has been determined in its free from, at 2.9 A resolution by molecular replacement. This antibody, used as an immmunogen, elicits the production of anti-anti-idiotypic antibodies that in turn neutralize the virus. The structure of the uncomplexed Fab was refined using constrained-restrained least squares minimization and simulated annealing in combination with conjugate gradient techniques to a crystallographic R of 0.22 based on 16,482 unique reflections between 20.0 and 2.9 A. The free antiidiotypic Fab shows, when compared to its complexed form, a 5 degrees rotation of its variable light with respect to its variable heavy domain and rearrangement of complementarity determining region loops, which permits optimization of the stereocomplementarity between interacting molecules. This finding supports the induced fit hypothesis for antibody antigen interaction.
抗独特型Fab 409.5.3是针对E2特异性猫传染性腹膜炎病毒中和抗体730.1.4制备的，其游离形式的晶体结构已通过分子置换法在2.9 Å分辨率下测定。该抗体用作免疫原，可引发抗抗独特型抗体的产生，进而中和病毒。未结合的Fab结构通过约束-限制最小二乘法最小化和模拟退火结合共轭梯度技术进行优化，基于20.0至2.9 Å之间的16,482个独立反射，晶体学R因子达到0.22。与结合形式相比，游离抗独特型Fab的可变轻链相对于可变重链结构域旋转了5°，互补决定区环发生了重排，这使得相互作用分子之间的立体互补性得以优化。这一发现支持了抗体-抗原相互作用的诱导契合假说。
