Bagheri Zeinab, Ranjbar Bijan, Latifi Hamid, Zibaii Mohammad Ismail, Moghadam Tahereh Tohidi, Azizi Azade
Department of Biophysics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
Department of Biophysics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran; Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
Int J Biol Macromol. 2015 Jan;72:806-11. doi: 10.1016/j.ijbiomac.2014.09.016. Epub 2014 Sep 22.
G-quadruplexes are supramolecular structures of G-rich nucleic acid, formed by non-canonical base pairing in the presence of specific environmental inducers. These structures have been vastly considered in diagnostic and therapeutic applications. However, detailed information on structure, optical properties and thermal stability of G-quadruplex potent oligonucleotides is scarce. Herein, optical properties and thermodynamic stability of AS1411 quadruplex is reported for various concentrations of potassium and lead ions. Circular dichroism showed that AS1411 ss-DNA folds into parallel conformation in the presence of metal ions and molecular crowding condition. UV-vis spectroscopy indicated formation of quadruplex and fluorescent spectroscopy revealed intercalation of PicoGreen in its structure, with enhancement of emission intensity upon increment of metal ion concentration. This investigation also proposes high-throughput and reliable analysis of AS1411 quadruplex's thermal stability by real-time PCR technique, which can be further applied for other quadruplex structures.
G-四链体是富含鸟嘌呤的核酸的超分子结构，由特定环境诱导剂存在下的非经典碱基配对形成。这些结构在诊断和治疗应用中已被广泛研究。然而，关于G-四链体有效寡核苷酸的结构、光学性质和热稳定性的详细信息却很匮乏。在此，报道了不同浓度钾离子和铅离子存在下AS1411四链体的光学性质和热力学稳定性。圆二色性表明，在金属离子和分子拥挤条件下，AS1411单链DNA折叠成平行构象。紫外可见光谱表明形成了四链体，荧光光谱揭示了PicoGreen嵌入其结构中，随着金属离子浓度的增加发射强度增强。本研究还提出了通过实时PCR技术对AS1411四链体的热稳定性进行高通量和可靠分析，该技术可进一步应用于其他四链体结构。
