Laboratoire Structure et Activité des Biomolécules Normales et Pathologiques, INSERM/UEVE U829, Université d'Evry val d'Essonne, Evry F-91025, France.
Langmuir. 2010 Feb 16;26(4):2618-23. doi: 10.1021/la902727b.
DNA processing by site-specific proteins on surface remains a challenging issue for nanobioscience applications and, in particular, for high-resolution imaging by atomic force microscopy (AFM). To obtain high-resolution conditions, mica, an atomically flat and negatively charged surface, is generally used. However, even though many specific DNA/protein interactions have already been observed by AFM, little is known about DNA accessibility to specific enzymes on mica. Here we measured the accessibility of adsorbed DNA to restriction endonucleases (EcoRI and EcoRV) using AFM. By increasing the concentration of divalent or multivalent salts, DNA adsorption on mica switches from weak to strong binding. Interestingly, while the accessibility of strongly bound DNA was inhibited, loosely adsorbed DNA was efficiently cleaved on mica. This result opens new perspective to study DNA/protein interaction by AFM or to modify specifically DNA on surface.
表面上的特定蛋白质对 DNA 的处理仍然是纳米生物技术应用的一个挑战，特别是对于原子力显微镜（AFM）的高分辨率成像。为了获得高分辨率的条件，通常使用原子级平整且带负电荷的云母。然而，尽管已经通过 AFM 观察到许多特定的 DNA/蛋白质相互作用，但对于特定酶在云母上对 DNA 的可及性知之甚少。在这里，我们使用 AFM 测量了吸附 DNA 对限制内切酶（EcoRI 和 EcoRV）的可及性。通过增加二价或多价盐的浓度，DNA 在云母上的吸附从弱结合转变为强结合。有趣的是，虽然强结合 DNA 的可及性受到抑制，但松散吸附的 DNA 在云母上被有效地切割。这一结果为通过 AFM 研究 DNA/蛋白质相互作用或在表面上特异性修饰 DNA 开辟了新的视角。
