Morihiro K, Hasegawa O, Mori S, Tsunoda S, Obika S
National Institute of Biomedical Innovation (NIBIO), 7-6-8 Saito-Asagi, Ibaraki, Osaka 567-0085, Japan.
Org Biomol Chem. 2015 May 14;13(18):5209-14. doi: 10.1039/c5ob00477b.
Oligonucleotides (ONs) modified with a locked nucleic acid (LNA) are widely used in the fields of therapeutics, diagnosis, and nanotechnology. There have been significant efforts towards developing LNA analogues bearing modified bridges to improve their hybridization ability, nuclease resistance, and pharmacokinetic profiles. Moreover, nucleobase modifications of LNA are useful strategies for the functionalization of ONs. Modifications of the C5-position of pyrimidine nucleobases are particularly interesting because they enable predictable positioning of functional groups in the major groove of the duplex. Here we report the synthesis of C5-azobenzene-functionalized LNA uridine (LNA-U(Az)) and properties of LNA-U(Az)-modified ONs, including isomerization properties, hybridization ability, and enzyme stability. LNA-U(Az) in ON is photo-isomerized effectively and reversibly by irradiation at 365 nm (trans to cis) and 450 nm (cis to trans). LNA-U(Az)-modified ONs show RNA-selective hybridization ability despite the large hydrophobic azobenzene moiety extending into the major groove of the duplex. The enzymatic stability of LNA-U(Az)-modified ONs is higher than that of natural and LNA-modified ONs with or without photo-irradiation. Our results indicate that LNA-U(Az) holds promise for RNA targeting and photo-switchable technologies.
用锁核酸（LNA）修饰的寡核苷酸（ONs）在治疗、诊断和纳米技术领域得到了广泛应用。人们在开发带有修饰桥的LNA类似物方面付出了巨大努力，以提高其杂交能力、核酸酶抗性和药代动力学特征。此外，LNA的核碱基修饰是寡核苷酸功能化的有用策略。嘧啶核碱基C5位的修饰尤其有趣，因为它们能够在双链体的大沟中可预测地定位官能团。在此，我们报告了C5 - 偶氮苯功能化的LNA尿苷（LNA-U(Az)）的合成以及LNA-U(Az)修饰的寡核苷酸的性质，包括异构化性质、杂交能力和酶稳定性。寡核苷酸中的LNA-U(Az)在365 nm（反式到顺式）和450 nm（顺式到反式）照射下能有效且可逆地进行光异构化。尽管大的疏水性偶氮苯部分延伸到双链体的大沟中，LNA-U(Az)修饰的寡核苷酸仍表现出对RNA的选择性杂交能力。LNA-U(Az)修饰的寡核苷酸在有无光照射的情况下，其酶稳定性均高于天然和LNA修饰的寡核苷酸。我们的结果表明，LNA-U(Az)在RNA靶向和光开关技术方面具有应用前景。
