旁侧序列对端粒DNA G-quadruplex热稳定性和折叠与去折叠动力学的影响  

Effect of Flanking Sequence on the Thermal Stability and Folding Kinetics of Telomere G-Quadruplex

作　　者：汤明亮[1] 赵勇 谭铮[1] 刘思阳[1] 

机构地区：[1]武汉大学生命科学学院,湖北武汉430072

出　　处：《武汉大学学报（理学版）》2006年第4期449-452,共4页Journal of Wuhan University:Natural Science Edition

基　　金：国家自然科学基金资助项目(204160758)

摘　　要：从热力学和动力学两个方面研究了旁侧序列对人端粒核心序列G3(T2AG3)3在钠离子溶液中所形成的G-quadruplex结构的影响.紫外吸收熔解实验表明G3(T2AG3)3一侧或两侧加上6个胸腺嘧啶核苷酸序列(T6)会明显降低G-quadruplex的相变温度(Tm).在3′端加上T6时Tm降低约5℃,在5′端加上T6时Tm降低约10℃,两侧同时加上T6时Tm降低16℃.采用表面等离子体共振(surface plasmon resonance,SPR)测定G-quadru-plex折叠和去折叠动力学的结果表明旁侧序列的加入同时降低了折叠和去折叠的速率常数(kf,ku),使折叠平衡常数(KF)由9.01降至7.44.上述结果表明旁侧序列的存在降低了G-quadruplex结构的稳定性.The G-rich strand of human telomeric DNA can fold into a four-stranded structure called G-quadruplex. In this work,we studied the effect of flanking sequence on the thermal stability and the folding/unfolding kinetics of G-quadruplex formed by the core sequence G3 （T2 AG3 ）3 of human telomeric DNA. We show that the introduction of flanking sequence greatly reduced the thermal stability of G-quadruplex as exhibited by decreased melting temperature （Tm）. On the other hand, the presence of flanking sequence also decreased the folding and unfolding rate constants （kf, ku）, resulting in a slightly decreased folding equilibrium constant （KF）.

关 键 词：端粒DNA Cr-quadruplex 旁侧序列 动力学 热力学 

分 类 号：Q6-3[生物学—生物物理学]