Durand M, Thuong N T, Maurizot J C
Centre de Biophysique Moléculaire Université d'Orléans, France.
J Biomol Struct Dyn. 1994 Jun;11(6):1191-202. doi: 10.1080/07391102.1994.10508063.
The interaction of berenil 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 was made by an oligonucleotide (dA)12-X-(dT)12-X-(dT)12, where x is a hexaethylene 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 berenil can bind to the triple helical structure. Spectral analysis shows that in the same ionic strength the drug bound to a double-stranded structure exhibits a conformation and an environment close to those observed in triple-stranded structure. The influence of the ionic strength on the interaction between the berenil molecule and the 36-mer is clearly demonstrated. We showed that when no NaCl salt is added in the buffer the triplex form of (dA)12-X-(dT)12-X-(dT)12 is stabilized by berenil whereas it is destabilized slightly by the dye when NaCl concentration is 1 M.
使用圆二色光谱法和热变性研究了小沟结合药物贝尼尔分子与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构成，其中x是一条六甘醇链，连接在一条链的3'磷酸基团和下一条链的5'磷酸基团之间。这种寡核苷酸能够自身回折形成非常稳定的三链体。圆二色光谱法表明贝尼尔可以与三链螺旋结构结合。光谱分析表明，在相同离子强度下，与双链结构结合的药物呈现出与三链结构中观察到的构象和环境相近的状态。离子强度对贝尼尔分子与36聚体之间相互作用的影响得到了明确证明。我们发现，当缓冲液中不添加氯化钠盐时，（dA）12-X-（dT）12-X-（dT）12的三链体形式会被贝尼尔稳定，而当氯化钠浓度为1 M时，该染料会使其略微不稳定。
