The 5'-GNC Site for DNA Interstrand Cross-Linking Is Conserved for Diepoxybutane Stereoisomers

详细信息    查看全文

• 作者：Julie T. Millard ; Trevor C. Hanly ; Kris Murphy ; and Natalia Tretyakova
• 刊名：Chemical Research in Toxicology
• 出版年：2006
• 出版时间：January 2006
• 年：2006
• 卷：19
• 期：1
• 页码：16 - 19
• 全文大小：105K
• 年卷期：v.19,no.1(January 2006)
• ISSN：1520-5010

文摘

The bifunctional alkylating agent 1,2,3,4-diepoxybutane forms interstrand DNA-DNA cross-linksbetween the N7 positions of deoxyguanosine residues on opposite strands of the duplex. For racemicdiepoxybutane, these cross-links predominate within 5'-GNC/3'CNG sequences, where N is any nucleotide.We used denaturing polyacrylamide gel electrophoresis (dPAGE) to examine the role of stereochemistryin the cross-linking reaction, subjecting a restriction fragment to cross-linking with S,S-DEB, R,R-DEB,or meso-DEB. DNA cross-links generated by each isomer were isolated by dPAGE, and the sites ofcross-linking were identified by sequencing gel analysis of DNA fragments generated by hot piperidinecleavage. We found that the 5'-GNC consensus sequence of racemic DEB is conserved, but the efficienciesof cross-linking vary, with S,S- > R,R- > meso-DEB. These results help explain the observed differencesbetween the biological activities of DEB stereoisomers.