基于T-Hg^(2+)-T及G四聚体自身熄灭能力的“Turn on”型单标记DNA荧光探针用于碘离子的检测  

Single-labeled "Turn on" Fluorescent Oligonucleotide Probe for Iodide Detection Based on T-Hg^(2+)-T and Inherent Quenching Ability of G-quadruplex

作　　者：朱颖[1] 刘沛[1] 羊小海[1] 何磊良[1] 李清照[1] 王青[1] 王柯敏[1] 黄晋[1] 刘剑波[1] 

机构地区：[1]湖南大学化学生物传感与计量学国家重点实验室,化学化工学院,生物纳米与分子工程湖南省重点实验室,长沙410082

出　　处：《高等学校化学学报》2012年第12期2651-2656,共6页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:91027000;20805012);科技部国际合作重大项目(批准号:2010DFB30300);教育部"新世纪优秀人才支持计划"(批准号:NCET-09-0338)资助

摘　　要：利用G四聚体可以熄灭荧光的特性以及T-Hg2+-T的特殊结构,发展了一种简便的"Turn on"型碘离子检测新方法.设计了一条5'端标有荧光基团的富T序列,3'端采用能形成G四聚体的富G序列代替传统的熄灭基团.加入汞离子后,富T序列形成T-Hg2+-T机构发生折叠,G四聚体靠近荧光基团,发生光诱导电子转移,使荧光被熄灭.若加入碘离子,碘离子会与汞离子形成较稳定的配合物,汞离子从DNA上被竞争下来,探针的荧光得以恢复,且荧光强度与50～500 nmol/L的碘离子呈良好线性关系,检出限为30 nmol/L.本方法选择性好,10倍于碘离子浓度的其它常见阴离子干扰较小.检测自来水样中碘离子的回收率为92%～109%,相对标准偏差RSD<4%(n=4).A simple and ＂Turn on＂ type iodide anion assay method was developed, based on the inherent quenching ability of G-quadruplex and fidelity of the ＂thymine-Hg^2＋-thymine＂ binding motif. A T-rich sequence was labeled with 6-carboxyfluorescein （FAM） at its 5′-end, nearby the 3′-end was a G-rich sequence which could form G-quadruplex structure instead of traditional quenchers. Upon addition of Hg^2＋ , T-rich sequence folded into a hairpin structure which led the G-quadruplex near to the FAM, and the FAM was quenched by the G-quadruplex owning to photoinduced electron transfer between the dye and the G-quadruplex. After the addition of iodide, the fluorescence of FAM recovered considering that iodide could bind with Hg^2＋. The novel method for the determination of iodide was developed in linear range of 50-500 nmol/L, with the detection limit（3σ） of 30 nmol/L. This proposed method was highly selective and other anions have no interfering effects on the determination, which was successfully applied for analysis of real samples with the recovery from 92%-109% and the RSD〈4% （n=4）.

关 键 词：碘离子 荧光 DNA探针 G四聚体 

分 类 号：O657[理学—分析化学]