Biomimetic modeling of the abstraction of H3′ by ribonucleotide reductases. 1,5-Hydrogen atom transfer of H3 to aminyl and oxyl, but not thiyl, free radicals in homoribofuranose derivatives
作者:Zhiqiang Guo、Mirna C Samano、Jan W Krzykawski、Stanislaw F Wnuk、Gregory J Ewing、Morris J Robins
DOI:10.1016/s0040-4020(99)00238-0
日期:1999.4
resulted in abstraction of H3 by a [1,5]-hydrogen atom shift. Transfer of 2H from the stannane to •C3 effected incorporation of deuterium at C3. Analogous treatment of 6-azido-6-deoxy-D-ribo-hexofuranose derivatives gave C3-deuterated aminosugars. In contrast, no deuterium incorporation was detected upon parallel treatment of 6-thio-D-ribo-hexofuranose derivatives. Abstraction of H3′ by a thiyl radical
用Bu 3 SnD / AIBN /苯/Δ从高纯呋喃核糖(5-脱氧-D-核糖-六呋喃糖)6- O-硝基酯生成6-氧自由基导致H3被[1,5]-氢原子夺取转移。的转移2从锡烷向•C3 H在C3实现氘的掺入。对6-叠氮基-6-脱氧-D-核糖-六呋喃糖衍生物的类似处理得到C3-氘代的氨基糖。相反,在平行处理6-硫代-D-核糖时未检测到氘掺入-六呋喃糖衍生物。巯基(•SCys)提取H3'是假定的第一步,反应是核糖核苷酸还原酶用于将核糖核苷酸转化为2'-脱氧核苷酸的反应。讨论了有关酶反应级联反应的结果,该级联反应将H3'的提取与C2'中不可逆的水损失耦合在一起。