Kawasaki A M, Casper M D, Freier S M, Lesnik E A, Zounes M C, Cummins L L, Gonzalez C, Cook P D
ISIS Pharmaceuticals, Carlsbad, California 92008.
J Med Chem. 1993 Apr 2;36(7):831-41. doi: 10.1021/jm00059a007.
"Uniformly" modified phosphodiester or phosphorothioate oligonucleotides incorporating 2'-deoxy-2'-fluoroadenosine, -guanosine, -uridine, and -cytidine, reported herein for the first time, when hybridized with RNA afforded consistent additive enhancement of duplex stability without compromising base-pair specificity. CD spectra of the 2'-deoxy-2'-fluoro-modified oligonucleotides hybridized with RNA indicated that the duplex adopts a fully A-form conformation. The 2'-deoxy-2'-fluoro-modified oligonucleotides in phosphodiester form were not resistant to nucleases; however, the modified phosphorothioate oligonucleotides were highly nuclease resistant and retained exceptional binding affinity to the RNA targets. The stabilizing effects of the 2'-deoxy-2'-fluoro modifications on RNA-DNA duplexes were shown to be superior to those of the 2'-O-methylribo substitutions. RNA hybrid duplexes with uniformly 2'-deoxy-2'-fluoro-modified oligonucleotides did not support HeLa RNase H activity; however, incorporation of the modifications into "chimeric" oligonucleotides has been shown to activate mammalian RNase H. "Uniformly" modified 2'-deoxy-2'-fluoro phosphorothioate oligonucleotides afforded antisense molecules with (1) high binding affinity and selectivity for the RNA target and (2) stability toward nucleases.
本文首次报道了“均匀”修饰的磷酸二酯或硫代磷酸酯寡核苷酸，其包含2'-脱氧-2'-氟腺苷、-鸟苷、-尿苷和-胞苷，当与RNA杂交时，能在不影响碱基对特异性的情况下，持续增强双链稳定性。与RNA杂交的2'-脱氧-2'-氟修饰寡核苷酸的圆二色谱表明，双链体呈现完全的A构象。磷酸二酯形式的2'-脱氧-2'-氟修饰寡核苷酸对核酸酶不具有抗性；然而，修饰的硫代磷酸酯寡核苷酸对核酸酶具有高度抗性，并对RNA靶标保持优异的结合亲和力。2'-脱氧-2'-氟修饰对RNA-DNA双链体的稳定作用优于2'-O-甲基核糖取代。与均匀2'-脱氧-2'-氟修饰寡核苷酸形成的RNA杂交双链体不支持HeLa RNase H活性；然而，已证明将这些修饰掺入“嵌合”寡核苷酸可激活哺乳动物RNase H。“均匀”修饰的2'-脱氧-2'-氟硫代磷酸酯寡核苷酸为反义分子提供了：（1）对RNA靶标的高结合亲和力和选择性，以及（2）对核酸酶的稳定性。
