Oxazole-type fluorophores show an increase of fluorescence intensity upon interaction with nucleic acids, and therefore can be used as tools for nucleic acid-sensing and fluorescence imaging. Here, we developed a novel stilbene-type fluorophore, MO-VN (1), consisting of a mono oxazole bearing a vinyl naphthalene moiety. This compound (1) was embedded in a trioxazole 2 and a cyclic hexaoxazole 3a. The fluorescence properties of 1, 2, and 3a were evaluated in the presence of various nucleic acid sequences. Compound 3 showed significant fluorescent enhancement upon interacting with G-quadruplex (G4) structure, which plays critical roles in various biological phenomena. Further structural development focusing on the vinyl naphthalene moiety of 3a afforded a turn-on type G4 ligand 3e that shows G4-specific fluorescence. Measurement of the fluorescence of 3e during titration of a telomeric DNA, telo24, with its C-rich complementary sequence, which unwinds the G4 structure, allowed us to monitor the dynamics of G4.

中文翻译：

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乙烯基萘六恶唑作为荧光开启型 G-四链体配体

恶唑型荧光团在与核酸相互作用时显示荧光强度增加，因此可用作核酸传感和荧光成像的工具。在这里，我们开发了一种新型二苯乙烯型荧光团 MO-VN ( 1 )，它由带有乙烯基萘部分的单恶唑组成。该化合物( 1 )包埋在三恶唑2和环状六恶唑3a中。在各种核酸序列存在下评估1、2和3a的荧光特性。化合物3在与 G-四链体 (G4) 结构相互作用时显示出显着的荧光增强，该结构在各种生物现象中起关键作用。进一步关注3a的乙烯基萘部分的结构开发提供了显示 G4 特异性荧光的开启型 G4 配体3e 。在滴定端粒 DNA telo24 的过程中测量3e的荧光，其富含 C 的互补序列展开 G4 结构，使我们能够监测 G4 的动态。