Professur für Physikalische Chemie, Mess- und Sensortechnik, Technische Universität Dresden, 01062 Dresden, Germany.
J Phys Condens Matter. 2011 May 11;23(18):184119. doi: 10.1088/0953-8984/23/18/184119. Epub 2011 Apr 20.
A novel technique for analyzing the conformational fluctuations of a single, surface-tethered DNA molecule by fluorescence microscopy is reported. Attaching a nanometer-sized fluorescent quantum dot to the free end of a λ-phage DNA molecule allows us to study the fluctuations of a native DNA molecule without the mechanical properties being altered by fluorescent dye staining. We report on the investigation of single-tethered DNA in both the unperturbed and the shear flow induced stretched state. The dependence of the observed fractional extension and the magnitude of fluctuations on the shear rate can be qualitatively interpreted by Brochard's stem-and-flower model. The cyclic dynamics of a DNA molecule is directly observed in the shear flow experiment.
本文报道了一种通过荧光显微镜分析单个表面固定 DNA 分子构象波动的新方法。通过将纳米级荧光量子点附着在 λ噬菌体 DNA 分子的自由端，我们可以在不改变荧光染料染色后机械性能的情况下研究天然 DNA 分子的波动。我们报告了在未受干扰和剪切流诱导拉伸状态下的单链 DNA 的研究结果。观察到的分数延伸和波动幅度对剪切率的依赖性可以通过 Brochard 的茎花模型进行定性解释。在剪切流实验中直接观察到 DNA 分子的循环动力学。
