Kim Hye-Young H, Wilkinson Amanda S, Harris Constance M, Harris Thomas M, Stone Michael P
Department of Chemistry, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37235, USA.
Biochemistry. 2003 Mar 4;42(8):2328-38. doi: 10.1021/bi020462k.
The conformation of the trans-anti-(1S,2R,3S,4R)-N(2)-[1-(1,2,3,4-tetrahydro-2,3,4-trihydroxybenz[a]anthracenyl)]-2'-deoxyguanosyl adduct in d(G(1)G(2)C(3)A(4)G(5)X(6)T(7)G(8)G(9)T(10)G(11)).d(C(12)A(13)C(14)C(15)A(16)C(17)C(18)T(19)G(20)C(21)C(22)), bearing codon 12 of the human N-ras protooncogene (underlined), was determined. This adduct had S stereochemistry at the benzylic carbon. Its occurrence in DNA is a consequence of trans opening by the deoxyguanosine amino group of (1R,2S,3S,4R)-1,2-epoxy-1,2,3,4-tetrahydrobenz[a]anthracenyl-3,4-diol. The resonance frequencies, relative to the unmodified DNA, of the X(6) H1' and H6 protons were shifted downfield, whereas those of the C(18) and T(19) H1', H2', H2' ', and H3' deoxyribose protons were shifted upfield. The imino and amino resonances exhibited the expected sequential connectivities, suggesting no interruption of Watson-Crick pairing. A total of 426 interproton distances, including nine uniquely assigned BA-DNA distances, were used in the restrained molecular dynamics calculations. The refined structure showed that the benz[a]anthracene moiety bound in the minor groove, in the 5'-direction from the modified site. This was similar to the (+)-trans-anti-benzo[a]pyrene-N(2)-dG adduct having S stereochemistry at the benzylic carbon [Cosman, M., De Los Santos, C., Fiala, R., Hingerty, B. E., Singh, S. B., Ibanez, V., Margulis, L. A., Live, D., Geacintov, N. E., Broyde, S., and Patel, D. J. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 1914-1918]. It differed from the (-)-trans-anti-benzo[c]phenanthrene-N(2)-dG adduct having S stereochemistry at the benzylic carbon, which intercalated in the 5'-direction [Lin, C. H., Huang, X., Kolbanovskii, A., Hingerty, B. E., Amin, S., Broyde, S., Geacintov, N. E., and Patel, D. J. (2001) J. Mol. Biol. 306, 1059-1080]. The results provided insight into how PAH molecular topology modulates adduct structure in duplex DNA.
测定了携带人N-ras原癌基因第12位密码子（下划线部分）的d(G(1)G(2)C(3)A(4)G(5)X(6)T(7)G(8)G(9)T(10)G(11)).d(C(12)A(13)C(14)C(15)A(16)C(17)C(18)T(19)G(20)C(21)C(22))中反式-反式-(1S,2R,3S,4R)-N(2)-[1-(1,2,3,4-四氢-2,3,4-三羟基苯并[a]蒽基)]-2'-脱氧鸟苷加合物的构象。该加合物在苄基碳处具有S构型。其在DNA中的出现是(1R,2S,3S,4R)-1,2-环氧-1,2,3,4-四氢苯并[a]蒽基-3,4-二醇的脱氧鸟苷氨基进行反式开环的结果。相对于未修饰的DNA，X(6) H1'和H6质子的共振频率向低场移动，而C(18)和T(19)的H1'、H2'、H2''和H3'脱氧核糖质子的共振频率向高场移动。亚氨基和氨基共振显示出预期的序列连接性，表明沃森-克里克配对没有中断。在受限分子动力学计算中使用了总共426个质子间距离，包括9个唯一指定的BA-DNA距离。优化后的结构表明，苯并[a]蒽部分结合在小沟中，从修饰位点沿5'方向。这与在苄基碳处具有S构型的(+)-反式-反式-苯并[a]芘-N(2)-dG加合物相似[科斯曼，M.，德洛斯桑托斯，C.，菲亚拉，R.，欣格蒂，B.E.，辛格，S.B.，伊瓦涅斯，V.，马古利斯，L.A.，利夫，D.，贾辛托夫，N.E.，布罗伊德，S.，和帕特尔，D.J.（1992年）美国国家科学院院刊89，1914 - 1918]。它与在苄基碳处具有S构型的(-)-反式-反式-苯并[c]菲-N(2)-dG加合物不同，后者沿5'方向嵌入[林，C.H.，黄，X.，科尔巴诺夫斯基，A.，欣格蒂，B.E.，阿明，S.，布罗伊德，S.，贾辛托夫，N.E.，和帕特尔，D.J.（2001年）分子生物学杂志306，1059 - 1080]。这些结果为多环芳烃分子拓扑结构如何调节双链DNA中的加合物结构提供了见解。
