Laboratory of Bioanalytical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań, Poland.
Molecules. 2018 Jun 9;23(6):1400. doi: 10.3390/molecules23061400.
Two conjugation methods using different linkers were applied for the investigation of the spectral characteristics and activity of G-quadruplex (G4)⁻hemin conjugates. For this purpose, two G-quadruplex-forming DNA sequences were selected, and then conjugated to a hemin molecule via either amine coupling or a click reaction. The products obtained via these two methods differed in their chemistry and the length of the linker between the DNA and hemin molecules. Spectral characteristics revealed that both methods produced conjugates that were more thermally stable than G4/hemin complexes. Despite similar spectral characteristics, the conjugates obtained via these two methods differed in their DNAzyme activity. G4⁻hemin conjugates obtained through amine coupling exhibited higher activity than conjugates obtained through a click reaction. This was potentially due to the length and chemistry of the linker, which was 30 atoms long following the click reaction, but only six atoms long following amine coupling. A longer connector favors higher flexibility, and hence, reduces the binding of hemin with G4. The aromatic groups present in the linker obtained through the click reaction can also disturb the G4⁻hemin interaction. However, the conjugation of G4 DNA to hemin via the click reaction was connected to a higher yield, and did not require any sophisticated synthesis equipment.
两种连接子的连接方法被应用于研究 G-四链体（G4）-血红素缀合物的光谱特性和活性。为此，选择了两条能形成 G-四链体的 DNA 序列，然后通过胺偶联或点击反应将血红素分子与 G4 连接。这两种方法得到的产物在化学性质和 DNA 与血红素分子之间的连接子长度上有所不同。光谱特性表明，这两种方法都产生了比 G4/血红素复合物更热稳定的缀合物。尽管光谱特性相似，但这两种方法得到的 DNAzyme 活性不同。通过胺偶联得到的 G4-血红素缀合物比通过点击反应得到的缀合物具有更高的活性。这可能是由于连接子的长度和化学性质不同，点击反应后的连接子长 30 个原子，而胺偶联后的连接子只有 6 个原子。更长的连接器有利于更高的灵活性，从而减少血红素与 G4 的结合。点击反应得到的连接子中的芳基基团也可以干扰 G4-血红素相互作用。然而，G4 DNA 通过点击反应与血红素的缀合与更高的产率相关，并且不需要任何复杂的合成设备。
