钾离子浓度依赖的铅离子稳定G-四链体构型转化  

K^+ Concentration-Dependent Conformational Change of Pb^(2+)-Stabilized G-quadruplex

作　　者：于泽 李晓宏[1] 李运超[1] 叶明富[2] YU Ze;LI Xiaohong;LI Yunchao;YE Mingfu(College of Chemistry,Beijing Normal University,Beijing 100875,P.R.China;School of Chemistry and Chemical Engineering,Anhui University of Technology,Maanshan,243002,Anhui Province,P.R.China)

机构地区：[1]北京师范大学化学学院,北京100875 [2]安徽工业大学化学与化工学院,安徽马鞍山243002

出　　处：《物理化学学报》2018年第11期1293-1298,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(21673022)资助项目~~

摘　　要：已有研究普遍认为铅离子(Pb^(2+))诱导富G适体链形成的G-四链体(Pb^(2+)-G4)比钾离子(K^+)诱导富G适体链形成的G-四链体(K^+-G4)更为稳定,因而Pb^(2+)可以置换K^+-G4中的K^+,而且K^+的存在不影响Pb^(2+)-G4的稳定性。有趣的是本研究发现K^+(20μmol·L^(-1)–1 mmol·L^(-1))不仅可以诱导10μmol·L^(-1) Pb^(2+)稳定的T2TT(Pb^(2+)-T2TT,杂合G4结构)发生构型转换,甚至还可取代Pb^(2+)-T2TT中的Pb^(2+),形成K^+稳定的T2TT (K^+-T2TT,平行G4结构),最终转化形成的K^+-G4结构与单独K^+诱导富G适体链形成K^+-G4的构型基本一致。随后,进一步考察了另外7条富G适体链,发现这一转化过程具有一定的普适性。该研究结果为理解G4构型转化以及内嵌离子交换提供了新的视角,也为拓展G4在生化分析和生物领域的应用提供了新的理论基础。DNA can adopt a diverse range of structural conformations,including duplexes,triplexes,and quadruplexes.Among these structures,G-quadruplexes have attracted much more attention of researchers.For G-rich DNA sequences,they can fold into multiple G-quadruplex conformations,such as parallel,antiparallel,or hybrid,and the exact conformation is influenced by G-rich DNA sequence,strand concentration,and binding cations.Among the factors influencing the G-quadruplex conformation and stability,cations played a really important role.Numerous studies have reported cation-dependent stability and topological changes of G-quadruplexes;however,most of studies have focused on the effect of individual cation(such as charge,radii,or hydration,etc.),and only few have assessed the effect of competition between cations at different concentrations.Actually,most biological and aqueous systems contained multiple cations and each of the cations had very different concentrations.Thus,investigation of the competitions between different cations(at different concentrations)for binding with G-quadruplexes and their effects on polymorphism of G-quadruplex is critical,which would improve our understanding of the roles of G-quadruplexes and assist us in further exploring their potential applications in biochemical,biomedical,and environmental systems.Under this situation,we focused on K+-and Pb^2+-stabilized G-quadruplex,two major cations that are usually used to stabilize G-quadruplex.It has been shown that for a given G-quadruplex forming DNA sequence,Pb^2+-stabilized G-quadruplex was more stable than K+-stabilized G-quadruplex,and Pb^2+could substitute K+in K+-stabilized G-quadruplex.However,the concentrations of K+that allow such a substitution are not completely studied.Previous studies have used G-quadruplex-based fluorescent,colorimetric,and electrochemical sensors for detecting Pb^2+,and these methods show excellent selectivity for Pb^2+over K+.Although G-quadruplex-based Pb^2+sensors were developed,their applications in real samples co

关 键 词：铅离子 钾离子 G-四链体 核酸适体链 构型转化 

分 类 号：O641.3[理学—物理化学]