Dynamics and stability of polymorphic human telomeric G-quadruplex under tension

• Main Authors: Efremov, Artem K., Phan, Anh Tuân, Yan, Jie, You, Huijuan, Zeng, Xiangjun, Xu, Yue, Lim, Ci Ji
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Physics::Geophysics and geomagnetism
• Online Access: https://hdl.handle.net/10356/104965; http://hdl.handle.net/10220/20391
• Institution: Nanyang Technological University

As critical DNA structures capping the human chromosome ends, the stability and structural polymorphism of human telomeric G-quadruplex (G4) have drawn increasing attention in recent years. This work characterizes the equilibrium transitions of single-molecule telomeric G4 at physiological K+ concentration. We report three folded states of telomeric G4 with markedly different lifetime and mechanical stability. Our results show that the kinetically favored folding pathway is through a short-lived intermediate state to a longer-lived state. By examining the force dependence of transition rates, the force-dependent transition free energy landscape for this pathway is determined. In addition, an ultra-long-lived form of telomeric G4 structure with a much stronger mechanical stability is identified.