Helm C A, Knoll W, Israelachvili J N
Department of Chemical and Nuclear Engineering, University of California, Santa Barbara 93106.
Proc Natl Acad Sci U S A. 1991 Sep 15;88(18):8169-73. doi: 10.1073/pnas.88.18.8169.
One distinguishing feature of "life" is that the physical forces between biological molecules and membrane surfaces are often highly specific, in contrast to nonspecific interactions such as van der Waals, hydrophobic, and electrostatic (Coulombic) forces. We have used the surface-forces-apparatus technique to study the specific "lock and key" or "ligand-receptor" interaction between two model biomembrane surfaces in aqueous solution. The membranes were lipid bilayers supported on mica surfaces; one carrying streptavidin receptors, the other exposing biotin ligand groups. We found that, although no unusual or specific interaction occurs between two avidin or two biotin surfaces, an avidin and a biotin surface exhibit a very strong, very short-range (less than 1 nm) attraction and that the binding mechanism involves equally specific molecular rearrangements. The results also show that highly specific biological interactions such as are involved in immunological recognition and cell-cell contacts may be studied at the molecular level and in real time by the surface-forces-apparatus technique.
“生命”的一个显著特征是，生物分子与膜表面之间的物理力通常具有高度特异性，这与范德华力、疏水力和静电（库仑）力等非特异性相互作用形成对比。我们利用表面力装置技术研究了水溶液中两个模型生物膜表面之间特定的“锁钥”或“配体-受体”相互作用。这些膜是支撑在云母表面的脂质双层；一个带有链霉亲和素受体，另一个暴露生物素配体基团。我们发现，虽然两个抗生物素蛋白或两个生物素表面之间不会发生异常或特异性相互作用，但抗生物素蛋白和生物素表面表现出非常强、非常短程（小于1纳米）的吸引力，并且结合机制涉及同样特异性的分子重排。结果还表明，诸如免疫识别和细胞间接触中所涉及的高度特异性生物相互作用，可以通过表面力装置技术在分子水平上进行实时研究。
