Guanidinium-Modified Phthalocyanines as High-Affinity G-Quadruplex Fluorescent Probes and Transcriptional Regulators
Guanidinium-Modified Phthalocyanines as High-Affinity G-Quadruplex Fluorescent Probes and Transcriptional Regulators
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DOI：
10.1002/anie.200903685
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发表时间：
2009-01-01
影响因子：
16.6
通讯作者：
Luedtke, Nathan W.
中科院分区：
文献类型：
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作者：
Alzeer, Jawad;Vummidi, Balayeshwanth R.;Luedtke, Nathan W.
G-四链体结构是DNA折叠模体中最有趣和最具特征的结构之一。[1]能够在体外形成稳定的G-四链体的DNA序列在体内具有广泛的功能，包括调节端粒稳定性，[2]调节启动子，[3]和病毒整合和重组。[4]许多研究小组已经开发了G-四链体的小分子配体，因为它们通过破坏端粒和/或启动子活性来抑制癌症生长的潜力。[5]已经报道了具有有用的荧光性质的G-四链体配体的更有限的选择。[6]尽管有这样显著的进展，表现出真正高亲和力（Kd 2nm）和高特异性（对双链体DNA的亲和力低> 5000倍）的G-四链体配体仍然难以捉摸。[5，6]可能需要这种有效和选择性的结合，以有效地与可以结合富含G的DNA和RNA的细胞蛋白质竞争，其Kd值在中pm范围内。[7]我们感兴趣的是高亲和力的G-四链体配体具有双重功能：他们应该表现出“打开”光致发光和调控基因表达的能力。[3，6]这些正交读数可以协同使用，以探测体内G-四链体结构和功能之间的潜在关系。我们正在探索这一新的概念，通过设计，合成和评估的一个新的家庭的四氮杂卟啉衍生物，同时变化的金属中心和胍基团可以调节DNA的特异性，细胞的摄取，和生物物理性能的酞菁支架。结构选择性G-四链体配体通常与构成G-四链体DNA的堆叠的G-四链体具有广泛的形状和电荷互补性。[5]例如，含吡啶鎓和铵的四氮杂卟啉衍生物相对于广泛研究的但非选择性的配体5，10，15，20-四（N-甲基-4-吡啶基）卟啉（TMPyP 4）表现出增强的G-四链体特异性。[8，9]这些分子以适度的亲和力（Kd= 100-200 nm）与G-四链体DNA结合，但尚未报道有关其细胞摄取，发光或转录调控的信息。[8]We对具有胍鎓基团的阳离子酞菁感兴趣，因为含胍鎓分子的细胞摄取和RNA/DNA亲和性优于类似的含铵化合物。[10]因此，我们合成了一个小家族的胍基酞菁（GPcs）处理四氨基锌酞菁2与各种双酰亚胺在离子液体（吡啶/吡啶盐酸盐）在1208 ℃（方案1）。[11]在这些条件下，从起始材料和产物中除去锌，得到不含金属的GPcs 3-5（方案1）。这些反应揭示了一种合成无金属酞菁的新方法，[11]但我们
G-quadruplex structures are among the most interesting and best-characterized DNA folding motifs.[1] DNA sequences that can form stable G-quadruplexes in vitro have been implicated in a wide range of functions in vivo, including the regulation of telomere stability,[2] the regulation of promoters,[3] and viral integration and recombination.[4] Many groups have developed small-molecule ligands for G-quadruplexes because of their potential to inhibit cancer growth by disrupting telomere and/or promoter activities.[5] A much more limited selection of G-quadruplex ligands with useful fluorescence properties has been reported.[6] Despite such notable progress, G-quadruplex ligands exhibiting truly high affinity (Kd 2 nm) and high specificity (> 5000-fold lower affinity to duplex DNA) have remained elusive.[5, 6] Such potent and selective binding might be needed to effectively compete with cellular proteins that can bind G-rich DNA and RNA with Kd values in the mid-pm range.[7] We are interested in high-affinity G-quadruplex ligands with dual functions: they should exhibit both “turn on” photoluminescence and the ability to regulate gene expression.[3, 6] These orthogonal readouts might be used in concert to probe potential relationships between G-quadruplex structure and function in vivo. We are exploring this new concept through the design, synthesis, and evaluation of a new family of porphyrazine derivatives where simultaneous variation of the metal center and guanidinium group can modulate the DNA specificity, cellular uptake, and photophysical properties of the phthalocyanine scaffold. Structure-selective G-quadruplex ligands often have extensive shape and charge complementarity with the stacked G-tetrads that constitute G-quadruplex DNA.[5] For example, pyridinium-and ammonium-containing porphyrazine derivatives exhibit enhanced G-quadruplex specificity relative to the widely studied, yet nonselective ligand 5, 10, 15, 20-tetrakis (N-methyl-4-pyridyl) porphine (TMPyP4).[8, 9] These molecules bind to G-quadruplex DNA with modest affinities (Kd= 100–200 nm), but no information regarding their cellular uptake, luminescence, or transcriptional regulation has been reported.[8]We are interested in cationic phthalocyanines with guanidinium groups because the cellular uptake and RNA/DNA affinity of guanidinium-containing molecules are better than the analogous ammonium-containing compounds.[10] We therefore synthesized a small family of guanidiniophthalocyanines (GPcs) by treating tetraaminozinc phthalocyanine 2 with various carbodiimides in an ionic liquid (pyridine/pyridine hydrochloride) at 1208C (Scheme 1).[11] Under these conditions, zinc was removed from both the starting materials and products to furnish the metal-free GPcs 3–5 (Scheme 1). These reactions revealed a novel method for the synthesis of metal-free phthalocyanines,[11] but we were