The (α-4) Photoconjugates of 5-Methylcytosine, 1,5-Dimethylcytosine, 1-Methylthymine and Thymidine
作者:Martin D. Shetlar、Janet Chung
DOI:10.1111/j.1751-1097.2011.01070.x
日期:2012.3
characteristic "double humped" profile, similar to that expected from overlaying the spectrum of parent nucleobase with that of a 2'-pyrimidone moiety. Preliminary results suggest that thymine and 5-methyl-2'-deoxycytidine (5-MedCyd) form analogous photoproducts. A variety of other previously unreported photoproducts are described as well for the 5-MeC, 1,5-diMeC and 5-MedCyd systems.
DNA中所含的嘧啶核碱基经历了多种光诱导反应,其中两个部分连接形成了产物(例如环丁烷二聚体和[6-4]加合物的形成)。在本文中,我们描述了一种新型的光结合反应,该反应已显示出会发生在5-甲基胞嘧啶(5-MeC),1,5-二甲基胞嘧啶(1,5-diMeC),1-甲基胸腺嘧啶和胸腺嘧啶核苷中;在该反应中,一个核碱基(或核苷)的5-甲基与第二部分的4-位连接。例如,5-MeC形成α-4'-(5'-甲基嘧啶-2'-一)-5-甲基胞嘧啶。母体化合物在-78.5摄氏度的冷冻水溶液中辐照后会产生各种(α-4)缀合物。这些化合物的UV光谱显示出特征性的“双峰”形,类似于通过将母体核碱基的光谱与2'-嘧啶酮部分的光谱重叠所预期的结果。初步结果表明,胸腺嘧啶和5-甲基-2'-脱氧胞苷(5-MedCyd)形成类似的光产物。对于5-MeC,1,5-diMeC和5-MedCyd系统,还描述了各种其他以前未报告的照片产品。