Ludden Manon J W, Péter Mária, Reinhoudt David N, Huskens Jurriaan
Laboratory of Supramolecular Chemistry and Technology, MESA+Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
Small. 2006 Oct;2(10):1192-202. doi: 10.1002/smll.200600147.
Streptavidin (SAv) is attached to beta-cyclodextrin (beta-CD) self-assembled monolayers (SAMs) via orthogonal host-guest and SAv-biotin interactions. The orthogonal linkers consist of a biotin functionality for binding to SAv and adamantyl functionalities for host-guest interactions at beta-CD SAMs. SAv complexed to excess monovalent linker in solution and then attached to a beta-CD SAM could be removed by rinsing with a 10 mM beta-CD solution. When SAv was attached to the beta-CD SAM via the divalent linker, it was impossible to remove SAv from the surface by the same rinsing procedure. This is interpreted by assuming that two SAv binding pockets are oriented towards the beta-CD SAM resulting in (labile) divalent and (stable) tetravalent beta-CD-adamantyl interactions for the mono- and divalent linkers, respectively. This was confirmed by experiments at varying beta-CD concentrations. When the [linker]/[SAv] ratio is reduced, a clear trend in the divalent-linker case is seen: the less linker the more protein could be removed from the surface. It is proven that the orthogonality of the binding motifs and the stability of the divalent linker at the beta-CD SAM allows the stepwise assembly of the complex at the beta-CD SAM by first adsorbing the linker, followed by SAv. This stepwise assembly allows the controlled heterofunctionalization of surface-immobilized SAv.
链霉亲和素（SAv）通过正交的主客体相互作用和SAv-生物素相互作用连接到β-环糊精（β-CD）自组装单分子层（SAMs）上。正交连接体由用于与SAv结合的生物素官能团和用于在β-CD SAMs上进行主客体相互作用的金刚烷基官能团组成。在溶液中与过量单价连接体复合然后连接到β-CD SAM上的SAv，可以通过用10 mM β-CD溶液冲洗而去除。当SAv通过二价连接体连接到β-CD SAM上时，通过相同的冲洗程序无法从表面去除SAv。这可以通过假设两个SAv结合口袋朝向β-CD SAM来解释，分别导致单价和二价连接体的（不稳定）二价和（稳定）四价β-CD-金刚烷基相互作用。这在不同β-CD浓度下的实验中得到了证实。当[连接体]/[SAv]比例降低时，在二价连接体的情况下可以看到明显的趋势：连接体越少，从表面去除的蛋白质越多。事实证明，结合基序的正交性以及二价连接体在β-CD SAM上的稳定性允许通过首先吸附连接体，然后吸附SAv，在β-CD SAM上逐步组装复合物。这种逐步组装允许对表面固定的SAv进行可控的异功能化。
