Lawrence L J, Kortt A A, Iliades P, Tulloch P A, Hudson P J
Biomolecular Research Institute, Parkville, Vic., Australia.
FEBS Lett. 1998 Apr 3;425(3):479-84. doi: 10.1016/s0014-5793(98)00292-0.
Electron microscopy of dimeric and trimeric single chain antibody Fv fragments (scFvs) complexed with anti-idiotype Fab fragments was used to reveal the orientation of antigen binding sites. This is the first structural analysis that discloses the multivalent binding orientation of scFv trimers (triabodies). Three different scFv molecules were used for the imaging analysis; NC10 scFv-5 and scFv-0, with five- and zero-residue linkers respectively between the VH and VL domains, were complexed with 3-2G12 anti-idiotype Fab fragments and 11-1G10 scFv-0 was complexed with NC41 anti-idiotype Fab fragments. The scFv-5 molecules formed bivalent dimers (diabodies) and the zero-linker scFv-0 molecules formed trivalent trimers (triabodies). The images of the NC10 diabody-Fab complex appear as boomerangs, not as a linear molecule, with a variable angle between the two Fab arms and the triabody-Fab complexes appear as tripods.
利用与抗独特型Fab片段复合的二聚体和三聚体单链抗体Fv片段（scFv）的电子显微镜技术来揭示抗原结合位点的方向。这是首次对scFv三聚体（三抗体）的多价结合方向进行结构分析。三种不同的scFv分子用于成像分析；VH和VL结构域之间分别具有五个和零个残基连接子的NC10 scFv-5和scFv-0，与3-2G12抗独特型Fab片段复合，11-1G10 scFv-0与NC41抗独特型Fab片段复合。scFv-5分子形成二价二聚体（双抗体），零连接子scFv-0分子形成三价三聚体（三抗体）。NC10双抗体-Fab复合物的图像呈现出回飞镖形状，而非线性分子，两个Fab臂之间有可变角度，三抗体-Fab复合物的图像则呈现出三脚架形状。
