α-DNA II. Synthesis of unnatural α-anomeric oligodeoxyribonucleotides containing the four usual bases and study of their substrate activities for nucleases
α-DNA II. Synthesis of unnatural α-anomeric oligodeoxyribonucleotides containing the four usual bases and study of their substrate activities for nucleases
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α-DNA II. 含有四种常用碱基的非天然 α-异头寡脱氧核糖核苷酸的合成及其核酸酶底物活性的研究
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发表时间：
1987
期刊：
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通讯作者：
C. Paoletti
中科院分区：
文献类型：
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作者：
F. Morvan;B. Rayner;J. Imbach;S. Thenet;J. Bertrand;J. Paoletti;C. Malvy;C. Paoletti
本文首次描述了含有四种常用碱基的α-寡核苷酸的合成。通过改进的磷酸三酯方法在溶液中获得了仅由 α-异头核苷酸单元组成的两种非天然六脱氧核糖核苷酸：α-[d(CpApTpGpCpG)] 和 α-[d(CpGpCpApTpG)]。起始材料是四个碱基保护的α-脱氧核糖核苷3a-d。嘧啶α-脱氧核苷3a和3b是通过自身异构化反应然后选择性去保护糖羟基来制备的，而两种嘌呤α-脱氧核苷3c和3d是通过糖基化反应制备的。在鸟嘌呤α-核苷衍生物的情况下，在O6位上引入补充碱基保护基团：N,N-二苯基氨基甲酰基，以避免寡核苷酸组装过程中的副反应。测试了六脱氧核苷酸 α-[d(CpApTpGpCpG)] 作为所选核酸内切酶和核酸外切酶的底物。在天然相应的β-六聚体被核酸酶S1和小牛脾磷酸二酯酶完全降解的条件下，α-寡核苷酸几乎保持完整。
This paper describes for the first time the synthesis of alpha-oligonucleotides containing the four usual bases. Two unnatural hexadeoxyribonucleotides: alpha-[d(CpApTpGpCpG)] and alpha-[d(CpGpCpApTpG)], consisting only of alpha-anomeric nucleotide units, were obtained by an improved phosphotriester method, in solution. Starting material was the four base-protected alpha-deoxyribonucleosides 3a-d. Pyrimidine alpha-deoxynucleosides 3a and 3b were prepared by self-anomerization reactions followed by selective deprotection of sugar hydroxyles, while the two purine alpha-deoxynucleosides 3c and 3d were prepared by glycosylation reactions. In the case of guanine alpha-nucleoside derivative a supplementary base-protecting group: N,N-diphenylcarbamoyl was introduced on O6-position in order to avoid side-reactions during oligonucleotide assembling. The hexadeoxynucleotide alpha-[d(CpApTpGpCpG)] was tested as substrate of selected endo- and exonucleases. In conditions where the natural corresponding beta-hexamer was completely degradated by nuclease S1 and calf spleen phosphodiesterase, the alpha-oligonucleotide remained almost intact.