中国物理B ›› 2015, Vol. 24 ›› Issue (12): 128704-128704.doi: 10.1088/1674-1056/24/12/128704
• SPECIAL TOPIC—8th IUPAP International Conference on Biological Physics • 上一篇 下一篇
李伟a, Wong Wei-Juanb, Lim Ci-Jib, 车海鹏a, 李明a, 严洁b, 王鹏业a
Li Wei (李伟)a, Wong Wei-Juanb, Lim Ci-Jib, Ju Hai-Peng (车海鹏)a, Li Ming (李明)a, Yan Jie (严洁)b, Wang Peng-Ye (王鹏业)a
摘要: Toroid formation is an important mechanism underlying DNA condensation, which has been investigated extensively by single-molecule experiments in vitro. Here, the de-condensation dynamics of DNA condensates were studied using magnetic tweezers combined with Brownian dynamics simulations. The experimental results revealed a surprising non-monotonic dependence of the unfolding rate on the force applied under strong adhesion conditions, resembling the catch-bond behavior reported in the field of ligand-receptor interactions. Simulation results showed that the different unfolding pathways of DNA condensate under large forces derive from the force-dependent deformation of the DNA toroid, which explains the catch-bond behavior of DNA condensate in the magnetic tweezers experiments. These results challenge the universality of the regular toroidal DNA unwrapping mechanism and provide the most complete description to date of multivalent cation-dependent DNA unwrapping under tension.
中图分类号: (Dynamics of biomolecules)