identified very recently in bacterial tRNAs. Our study on the synthesis of geS2Ura-containing oligonucleotides (geS2U-RNA and geS2dU-DNA) revealed fast substitution of S-geranyl moiety by methylamine (frequently used in oligonucleotide deprotection procedures) or n-butylamine, providing the corresponding N2-alkyl isocytosine (R2isoCyt) derivatives. To retain the S-geranyl moiety in the DNA or RNA chains
S-甘
氨酰化2-
硫尿苷(geS2Us)是细菌tRNA中最近发现的独特的疏
水修饰核苷。我们对包含geS2Ura的寡核苷酸(geS2U-RNA和geS2dU-DNA)的合成研究表明,S-香叶基部分被
甲胺(经常用于寡核苷酸脱保护步骤)或
正丁胺快速取代,从而提供了相应的N2-烷基异
胞嘧啶( R2isoCyt)衍
生物。为了将S-香叶基部分保留在DNA或RNA链中,应使用具有8 M
乙醇氨的最佳脱保护方案。带有R2isoCyt杂环的低聚物(R2isoC-RNA和R2isodC-DNA)的疏
水性低于相应的S2U和geS2U修饰的低聚物,而与先前报道的数据相反,geS2dU-DNA和geS2U-RNA的亲脂性明显高于亲本S2Ura寡核苷酸。热力学研究表明:(a)geS2Ura和R2isoCyt修饰的寡聚体均显示出与DNA和RNA模板相似的杂交特性,(b)R2isoCyt核碱基优先与
鸟嘌呤而非DNA / DNA和RNA