Totsingan Filbert, Tedeschi Tullia, Sforza Stefano, Corradini Roberto, Marchelli Rosangela
Dipartimento di Chimica Organica e Industriale Università di Parma, 43100 Parma, Italy.
Chirality. 2009 Jan;21(1):245-53. doi: 10.1002/chir.20659.
A chiral peptide nucleic acid (PNA) beacon containing a C-5 modified monomer based on L-lysine was synthesized. The terminal amino group of the lysine side chain was linked to a spacer for future applications on surfaces. The PNA beacon bears a carboxyfluorescein fluorophore and a dabcyl quencher at opposite ends. The DNA binding properties were compared with those of a homologous PNA beacon containing only achiral monomers. Both beacons underwent a fluorescence increase in the presence of complementary DNA, with higher efficiency and higher selectivity (evaluated using single mismatched DNA sequences) observed for the chiral monomer containing PNA. Ion exchange (IE) HPLC with fluorimetric detection was used in combination with the beacon for the selective detection of complementary DNA. A fluorescent peak corresponding to the PNA beacon:DNA duplex was observed at a very low detection limit (1 nM). The discriminating capacity of the chiral PNA beacon for a single mismatch was found to be superior to those observed with the unmodified one, thus confirming the potency of chirality for increasing the affinity and specificity of DNA recognition.
合成了一种基于L-赖氨酸的含有C-5修饰单体的手性肽核酸（PNA）信标。赖氨酸侧链的末端氨基与一个间隔臂相连，以便将来用于表面应用。该PNA信标在相对的两端分别带有一个羧基荧光素荧光团和一个二甲基氨基偶氮苯猝灭剂。将其DNA结合特性与仅含有非手性单体的同源PNA信标进行了比较。在互补DNA存在的情况下，两种信标都发生了荧光增强，其中含有手性单体的PNA表现出更高的效率和更高的选择性（使用单错配DNA序列评估）。离子交换（IE）高效液相色谱结合荧光检测与信标联用，用于选择性检测互补DNA。在非常低的检测限（1 nM）下观察到了与PNA信标：DNA双链体相对应的荧光峰。发现手性PNA信标对单错配的区分能力优于未修饰的信标，从而证实了手性对于提高DNA识别亲和力和特异性的作用。
