4-4-20-ANTI-FLUORESCYL IGG FAB' RECOGNITION OF MEMBRANE-BOUND HAPTEN - DIRECT EVIDENCE FOR THE ROLE OF PROTEIN AND INTERFACIAL STRUCTURE
4-4-20-ANTI-FLUORESCYL IGG FAB' RECOGNITION OF MEMBRANE-BOUND HAPTEN - DIRECT EVIDENCE FOR THE ROLE OF PROTEIN AND INTERFACIAL STRUCTURE
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DOI：
10.1021/bi00036a020
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发表时间：
1995-09-12
期刊：
影响因子：
2.9
通讯作者：
RINGSDORF, H
中科院分区：
文献类型：
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作者：
LECKBAND, DE;KUHL, T;RINGSDORF, H
表面力装置用于鉴定控制单克隆4-4-20抗荧光IgG Fab'片段与荧光素呈递的支撑平面双层的相互作用的分子力。在远距离，定向Fab'和荧光素单层之间的静电力由抗原结合位点周围的蛋白质外部的组成控制，而不是由总蛋白质电荷控制。在pH > PIFab'下Fab'单层的测量的正静电势与暴露的Fab'表面的结构一致，其中在抗原结合位点的口处的正电荷环主导局部静电表面性质。用变性Fab'测量的静电力的实质性差异进一步证明了测量的静电表面性质和随后的长程相互作用力由蛋白质表面组成控制。在短范围内，Fab '介导的粘附的强度不仅由荧光素系链的长度调节，而且还由膜水合作用调节。在膜表面的空间水合屏障的粘附强度降低成比例的影响范围。这些结果提供了直接的证据表明，远程蛋白质与固定化配体的相互作用是由蛋白质和膜表面组合物控制，而短程，特异性结合是由蛋白质结构和膜界面性质调制。
The surface forces apparatus was used to identify the molecular forces that control the interactions of monoclonal 4-4-20 antifluorescyl IgG Fab' fragments with fluorescein-presenting supported planar bilayers. At long range, the electrostatic force between oriented Fab' and fluorescein monolayers was controlled by the composition of the protein exterior surrounding the antigen-combining site rather than by the overall protein charge. The measured positive electrostatic potential of the Fab' monolayer at pH > PIFab' was consistent with the structure of the exposed Fab' surface in which a ring of positive charge at the mouth of the antigen-combining site dominates the local electrostatic surface properties. Substantial differences in the electrostatic forces measured with denatured Fab' further demonstrated that the measured electrostatic surface properties and the consequent long-range interaction forces are controlled by the protein surface composition. At short range, the strength of the Fab'-mediated adhesion was modulated not only by the length of the fluorescein tether but also by membrane hydration. Steric hydration barriers at the membrane surface reduced the adhesion strength in proportion to their range of influence. These results provide direct evidence that long-range protein interactions with immobilized ligands are controlled by both the protein and the membrane surface compositions, while short-range, specific binding is modulated by both the protein structure and the membrane interfacial properties.