Engineering Bisquinolinium/Thiazole Orange Conjugates for Fluorescent Sensing of G-Quadruplex DNA
Engineering Bisquinolinium/Thiazole Orange Conjugates for Fluorescent Sensing of G-Quadruplex DNA
复制标题
DOI：
10.1002/anie.200805613
复制
发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Monchaud, David
中科院分区：
文献类型：
--
作者：
Yang, Peng;De Cian, Anne;Monchaud, David
尽管在过去的几十年里，G-四链DNA的体外存在已经被彻底研究，[1]它在体内的相关性仍然是一个有争议的问题。[2]所提供的证据的间接性导致了对G-四链DNA是否真的在细胞中形成的怀疑。[3]为了解决这个问题，必须开发检测细胞中G-四链结构的化学、生物物理和生化工具。最近，一项使用氚G-四链配体[~3H]-360A的染色体放射学研究给出了有趣的推动力；[4]然而，处理放射性探针需要特定的条件，因此不能扩展到常规应用。另一种方法依赖于荧光探针的概念，由于检测系统的快速发展，荧光探针在生物学中的应用越来越多。理想情况下，荧光检测需要一个探针，它的荧光在与给定的靶结合后显著增强；这项任务在G-四链DNA的情况下尤其复杂，因为大多数有机荧光团都被鸟嘌呤猝灭。[5]因此我们决定进一步研究这一具有挑战性的方法，特别是因为到目前为止报道的G-四链荧光配体很少。[6]吡哆二甲酰胺(PDC)双喹啉系列似乎是最有吸引力的G-四链配体之一，因为它具有高亲和力和选择性，以及它快速和方便的合成途径。[4，7]不幸的是，PDC衍生物只是弱荧光，因此不适用于G-四链检测。另一方面，噻唑橙(TO)是一种特殊的DNA探针，因为它的荧光在与DNA结合后大大增加(%500倍)，而它在溶液中游离时表现出非常低的量子产率。[8]有趣的是，TO已被证明与G-
Whereas the in vitro existence of G-quadruplex DNA has been thoroughly studied during the past decades,[1] its in vivo relevance is still a matter of controversy.[2] The indirect nature of the provided evidence has led to scepticism about whether G-quadruplex DNA actually forms in cells.[3] To address this issue, chemical, biophysical, and biochemical tools that will detect G-quadruplex structures in cells must be developed. Interesting impetus has been given recently by a chromosomal radiographic study using the tritiated G-quadruplex ligand [3H]-360A;[4] nevertheless, the handling of radioactive probes requires specific conditions and hence cannot be extended to routine applications. An alternative approach relies on the conception of fluorescent probes which are increasingly used in biology owing to the rapid evolution of detection systems. Ideally fluorescence detection requires a probe whose fluorescence is significantly enhanced upon binding to a given target; this task is particularly complicated in the case of G-quadruplex DNA since most organic fluorophores are quenched by guanines.[5] We thus decided to further investigate this challenging approach, particularly since very few examples of fluorescent G-quadruplex ligands have been reported to date.[6]The pyridodicarboxamide (PDC) bisquinolinium series appears as one of the most attractive G-quadruplex ligands because of its high affinity and selectivity, along with its rapid and convenient synthetic access.[4, 7] Unfortunately, PDC derivatives are only weakly fluorescent and therefore not usable for G-quadruplex detection. On the other hand, thiazole orange (TO) is an exceptional DNA probe, since its fluorescence is greatly increased (% 500-fold) upon binding to DNA, whereas it exhibits a very low quantum yield when free in solution.[8] Interestingly, TO has been shown to bind G-