24小时热门版块排行榜

返回列表

当前主题已经存档。

superdujb

金虫 (初入文坛)

应助: 0 (幼儿园)
金币: 556
散金: 90
帖子: 39
在线: 59.6小时
虫号: 752393
注册: 2009-04-19
专业: 波谱分析与成像分析

[交流] 【求助】+【有效期到9月2日】【翻译段落】

Oligonucleotides incorporating 7-(octa-1,7-diynyl) derivatives of 8-aza-7-deaza-2'-deoxyguanosine (2d)
were prepared by solid-phase synthesis. The side chain of 2d was introduced by the Sonogashira cross
coupling reaction and phosphoramidites (3a, 3b) were synthesized. Duplexes containing 2d are more
stabilized compared to those incorporating the non-functionalized 8-aza-7-deaza-2'-deoxyguanosine
(2a) demonstrating that these side chains have steric freedom in duplex DNA. Nucleoside 2d as well as
2d-containing oligonucleotides were conjugated to the non-ﬂuorescent 3-azido-7-hydroxycoumarin 15
by the Huisgen-Meldal-Sharpless ‘click’ reaction. Pyrazolo[3,4-d]pyrimidine nucleoside conjugate 16
shows a much higher ﬂuorescence intensity than that of the corresponding pyrrolo[2,3-d]pyrimidine
derivative 17. The quenching in the dye conjugate 17 was found to be stronger on the stage of
monomeric conjugates than in single-stranded or duplex DNA. Nucleobase-dye contact complexes are
suggested which are more favourable in the monomeric state than in the DNA chain when the
nucleobase is part of the stack. The side chains with the bulky dye conjugates are well accommodated in
DNA duplexes thereby forming hybrids which are slightly more stable than canonical DNA.

回复此楼