Modified oligonucleotides containing both A-form conformation geometry and B-from conformation geometry nucleotides are disclosed. The B-form geometry allows the oligonucleotide to serve as substrates for RNase H when bound to a target nucleic acid strand. The A-form geometry imparts properties to the oligonucleotide that modulate binding affinity and nuclease resistance. By utilizing C2′ endo sugars or O4′ endo sugars, the B-form characteristics are imparted to a portion of the oligonucleotide. The A-form characteristics are imparted via use of either 2′-O-modified nucleotides that have 3′ endo geometries or use of end caps having particular nuclease stability or by use of both of these in conjunction with each other.
本发明揭示了含有A形构象几何和B形构象几何核苷酸的修饰寡核苷酸。B形构象几何使寡核苷酸在结合到目标核酸链时作为RNase H的底物。A形构象几何赋予寡核苷酸特定的性质,调节其结合亲和力和
核酸酶抗性。通过利用C2′内糖或O4′内糖,将B形特性赋予寡核苷酸的一部分。通过使用具有3′内糖几何的2′-O修饰核苷酸或具有特定
核酸酶稳定性的末端帽,或同时使用这两种方法来赋予A形特性。