Triple helix stabilization by covalently linked DNA–bisbenzimidazole conjugate synthesized by maleimide–thiol coupling chemistry

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• 作者：Akash K. Jain ; Satish Kumar Awasthi and Vibha Tandon
• 关键词：Triple helix ; Heterobifunctional ; Crosslinking reagent ; Maleimide conjugate ; Induced CD signal ; Minor groove binders
• 刊名：Bioorganic and Medicinal Chemistry
• 出版年：2006
• 出版时间：15 September 2006
• 年：2006
• 卷：14
• 期：18
• 页码：6444-6452
• 全文大小：801 K

文摘

Tethering of BBZPNH₂, an analogue of the Hoechst 33258, with a 14 nucleotide long DNA sequence with the help of succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), a heterobifunctional crosslinking reagent, using DMF/ water as solvent yields a conjugate which effectively stabilizes the triple helix. The above conjugate was hybridized with 26 bp long double stranded (ds) DNA having 14 bp long polypurine–polypyrimidine stretch to form a pyrimidine motif triple helix. The above conjugate increases the thermal stability of both the transitions, that is, triple helix to double helix by 12 °C and double helix to single strand transition by 16 °C for the triple helix formed with conjugated TFO over the triple helix made from non-conjugated TFO. Fluorescence and circular dichroism spectra recorded at different temperatures confirm the presence of minor groove binding bisbenzimidazole in the AT-rich minor groove of dsDNA even after the major groove bound TFO separates out.