Cyanine dyes as intercalating agents: Kinetic and thermodynamic studies on the DNA/Cyan40 and DNA/CCyan2 systems
Cyanine dyes as intercalating agents: Kinetic and thermodynamic studies on the DNA/Cyan40 and DNA/CCyan2 systems
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DOI：
10.1529/biophysj.105.059790
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发表时间：
2005-07-01
影响因子：
3.4
通讯作者：
Yarmoluk, S
中科院分区：
文献类型：
--
作者：
Biver, T;De Biasi, A;Yarmoluk, S
花菁与核酸的相互作用伴随着它们的光学性质的强烈变化。因此，这些分子在生物学和医学中有许多应用。由于没有关于DNA/花青体系结合机理的详细资料，因此，对花青Cyan 40 [3-甲基-2-甲基-4-（3-甲基-2-甲基-4-氧代苯基）-2-氧代苯基]与DNA的结合的动力学和平衡进行了T-jump研究。（1，2，6-三甲基-4（1H）吡啶亚甲基）-苯并噻唑鎓离子]和CCyan 2 [3-甲基-2-[2-甲基-3-[（3-甲基-2（3 H）-苯并噻唑亚基）-1-丙烯基]-苯并噻唑鎓离子]与CT-DNA的反应在25 ℃、pH 7和各种离子强度下进行。染料吸收带的Bathochromic位移DNA添加后，聚合物熔点位移（Δ T = 8-10摄氏度），网站大小的测定（n = 2），和逐步动力学一致，表明研究的花青结合到CT-DNA主要通过嵌入。用poly（dA-dT）.poly（dA-dT）和poly（dG-dC）.poly（dG-dC）的测量显示CCyan 2对G-C碱基对的公平选择性。T-跳跃实验表明两个系统的动力学效应。结合过程中讨论的顺序D + S可逆箭头D，S可逆箭头DSI可逆箭头DSII，这导致首先快速形成的外部复合物D，S，然后部分嵌入的复合物DSI，这反过来又转化为DSII，更稳定的嵌入。吸收光谱表明，这两种染料倾向于自聚集; CCyan 2自聚集的动力学进行了研究，通过T-跳跃弛豫和结果解释的二聚体形成。
The interaction of cyanines with nucleic acids is accompanied by intense changes of their optical properties. Consequently these molecules find numerous applications in biology and medicine. Since no detailed information on the binding mechanism of DNA/cyanine systems is available, a T-jump investigation of the kinetics and equilibria of binding of the cyanines Cyan40 [3-methyl-2-(1,2,6-trimethyl-4(1H)pyridinylidenmethyl)-benzothiazolium ion] and CCyan2 [3-methyl-2-[2-methyl-3-(3-methyl-2(3H)-benzothiazolylidene)-1-propenyl]-benzothiazolium ion] with CT-DNA is performed at 25 degrees C, pH 7 and various ionic strengths. Bathochromic shifts of the dye absorption band upon DNA addition, polymer melting point displacement (Delta T = 8-10 degrees C), site size determination (n = 2), and stepwise kinetics concur in suggesting that the investigated cyanines bind to CT-DNA primary by intercalation. Measurements with poly(dA-dT).poly(dA-dT) and poly(dG-dC).poly(dG-dC) reveal fair selectivity of CCyan2 toward G-C basepairs. T-jump experiments show two kinetic effects for both systems. The binding process is discussed in terms of the sequence D + S reversible arrow D,S reversible arrow DSI reversible arrow DSII, which leads first to fast formation of an external complex D, S and then to a partially intercalated complex DSI which, in turn, converts to DSII, a more stable intercalate. Absorption spectra reveal that both dyes tend to self-aggregate; the kinetics of CCyan2 self-aggregation is studied by T-jump relaxation and the results are interpreted in terms of dimer formation.