Li Dawei, Peng Peiwen, Yang Zhaoqi, Lv Bei
The Southern Modern Forestry Collaborative Innovation Center, College of Biology and the Environment, Nanjing Forestry University 159 Longpan Road Nanjing 210037 China
School of Pharmaceutical Sciences, Jiangnan University Wuxi 214122 China.
RSC Adv. 2019 Aug 21;9(45):26248-26251. doi: 10.1039/c9ra06370f. eCollection 2019 Aug 19.
G-quadruplex is a secondary structure of nucleic acids that plays crucial roles in many significant biological processes. Potential G-quadruplex-forming sequences exist widely in various regions of the genome such as telomeres and gene promoters. In spite of the fact that G-quadruplex can be readily assembled from a single-stranded segment of DNA, its formation from duplex DNA is very difficult under physiological conditions because Watson-Crick interactions in guanine rich segments need to be weakened first. It is demonstrated in our studies that intrastrand G-quadruplex generated from a perfectly matched guanine-rich duplex in a circular DNA as a result of significant quadruplex stabilization and duplex destabilization created by the combined actions of negative DNA supercoiling and molecular crowding conditions.
G-四链体是核酸的二级结构,在许多重要的生物学过程中发挥着关键作用。潜在的G-四链体形成序列广泛存在于基因组的各个区域,如端粒和基因启动子。尽管G-四链体可以很容易地从单链DNA片段组装而成,但在生理条件下,从双链DNA形成G-四链体非常困难,因为富含鸟嘌呤的片段中的沃森-克里克相互作用需要首先被削弱。我们的研究表明,在环状DNA中,由于负超螺旋和分子拥挤条件的共同作用,导致完全匹配的富含鸟嘌呤的双链显著稳定四链体并使双链不稳定,从而产生链内G-四链体。