Durand M, Thuong N T, Maurizot J C
Centre de Biophysique Moléculaire, Orléans, France.
Biochimie. 1994;76(2):181-6. doi: 10.1016/0300-9084(94)90011-6.
The interaction of Hoechst 33258 molecule, a minor groove binding drug, with T-A-T triple helix and A-T double helix was studied using circular dichroism spectroscopy and thermal denaturation. The triple helix consisted of an oligonucleotide (dA)12-x-(dT)12-x-(dT)12, where x is a hexa-ethylene glycol chain bridged between the 3' phosphate of one strand and the 5' phosphate of the following strand. This oligonucleotide is able to fold back on itself to form a very stable triplex. Circular dichroism spectroscopy demonstrates that Hoechst 33258 can bind to the triple helical structure. Spectral analysis shows that the bound drug exhibits a conformation and an environment slightly different in double-stranded and in triple-stranded structure. The affinity to the triple stranded structure is found smaller than to the double stranded one. Thermal denaturation experiments demonstrate that Hoechst 33258 destabilizes the triplex whereas it stabilizes the duplex.
使用圆二色光谱法和热变性研究了小沟结合药物Hoechst 33258分子与T-A-T三链螺旋和A-T双链螺旋的相互作用。三链螺旋由寡核苷酸（dA）12-x-（dT）12-x-（dT）12组成，其中x是一条链的3'磷酸与下一条链的5'磷酸之间桥接的六乙二醇链。这种寡核苷酸能够自身折叠形成非常稳定的三链体。圆二色光谱法表明Hoechst 33258可以与三链螺旋结构结合。光谱分析表明，结合的药物在双链和三链结构中表现出略有不同的构象和环境。发现其对三链结构的亲和力小于对双链结构的亲和力。热变性实验表明，Hoechst 33258使三链体不稳定，而使双链体稳定。
