Jahnz-Wechmann Zofia, Lisowiec-Wachnicka Jolanta, Framski Grzegorz, Kosman Joanna, Boryski Jerzy, Pasternak Anna
Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland.
Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89 b, 61-614 Poznań, Poland.
Bioorg Chem. 2017 Apr;71:294-298. doi: 10.1016/j.bioorg.2017.02.014. Epub 2017 Mar 2.
Herein, we present comprehensive physicochemical and structural analysis of various DNA hairpins modified with pyrrolo-2'-deoxycytidine (Py-dC) derivatives. The introduction of modified Py-dC in most cases causes minor decrease of hairpin thermodynamic stability. The energetically unfavorable effect is more pronounced when modified residue is present within hairpin loop. Our studies indicate that thermodynamic effects induced by all Py-dC derivatives are net results of increased stacking interactions caused by larger surface of pyrrolo-2'-deoxycytidine aromatic ring and unfavorable effect implied by the presence of additional side chains. The CD spectra of all modified hairpins are similar to unmodified hairpin indicating that the presence of Py-dC derivatives does not disrupt the secondary structure of DNA. Interestingly, the presence of various side chains can increase fluorescent discrimination of paired and unpaired regions of DNA. The fluorescence observed for hairpins modified within loop is significantly quenched when Py-dC derivative is present in the stem region.
在此，我们展示了对用吡咯并-2'-脱氧胞苷（Py-dC）衍生物修饰的各种DNA发夹进行的全面物理化学和结构分析。在大多数情况下，修饰的Py-dC的引入会导致发夹热力学稳定性略有下降。当修饰残基存在于发夹环内时，能量上不利的影响更为明显。我们的研究表明，所有Py-dC衍生物诱导的热力学效应是由吡咯并-2'-脱氧胞苷芳香环较大表面引起的堆积相互作用增加以及额外侧链的存在所暗示的不利影响的净结果。所有修饰发夹的圆二色光谱与未修饰发夹相似，表明Py-dC衍生物的存在不会破坏DNA的二级结构。有趣的是，各种侧链的存在可以增加对DNA配对和未配对区域的荧光区分。当Py-dC衍生物存在于茎区域时，在环内修饰的发夹所观察到的荧光会显著淬灭。
