Marked Differences in Base Selectivity between DNA and the Free Nucleotides upon Adduct Formation from Bay- and Fjord-Region Diol Epoxides
作者:SreenivasaRao Vepachedu、Naiqi Ya、Haruhiko Yagi、Jane M. Sayer、Donald M. Jerina
DOI:10.1021/tx000073w
日期:2000.9.1
85% dA adducts on reaction with DNA. With the BaP DEs, 60-77% of the exocyclic amino group adducts formed upon competitive reaction with the free nucleotides are derived from dGMP. The observed dG selectivity of these BaP DEs is much smaller with the nucleotide mixture than it is with DNA, leading to the conclusion that DNA structure has a much larger modifying effect on the base selectivity of the
由3,4-二羟基-1,2-环氧-1,2,3,4-四氢苯并[c]菲和7,8-二羟基-9,10-的四个旋光异构体中的每一个形成的加合物的分布将环氧,7,8,9,10-四氢苯并[a]((BcPh和BaP二醇环氧化物)与脱氧腺苷和脱氧鸟苷5'-单磷酸酯的等摩尔混合物反应,与这些二醇环氧化物(DEs)的已知加合物分布进行了比较在体外与小牛胸腺DNA反应后。在dAMP和dGMP的等摩尔混合物(总计100 mM)的存在下,BaP(约40-60%)和BcPh(约30-40%)相对于四醇的所有类型加合物形成效率相当)二醇环氧化合物。这与DNA观察到的四醇和加合物之间的分配不同,其中BcPh DE形成的加合物比BaP DE更有效。对于其中苯甲基羟基和环氧基是反式(DE-2)的DE非对映异构体,dAMP / dGMP混合物中游离核苷酸的环外氨基优先反式与顺式开环。从质上讲,这类似于这些异构体与DNA反应时形成顺