DNA Sequence Specificity of Mitomycin Cross-Linking

Sally P. Teng, Sarah A. Woodson, Donald M. Crothers

Research output: Contribution to journalArticlepeer-review

Abstract

Using a gel electrophoresis assay, we show that the target DNA sequence cross-linked by A-methylmitomycin A, its aziridinomitosene, and mitomycin C is CpG, in strong preference over GpC. The yield per CpG site increases as the number of successive CpG sequences increases. Molecular modeling reveals no systematic difference between the energies of mitomycin cross-links at CpG in comparison with GpC. However, the distance between guanine amino groups in CpG sequences is nearly the same as the distance in the cross-linked adduct, whereas the amino group separation at GpC sites is substantially larger in the starting DNA than in the adduct. We suggest that the favorable placement of the second reaction center in CpG greatly accelerates the second step in the cross-linking reaction. As shown by a competition assay, mitomycins bind A•T and G•C sequences noncovalently equally well, even though the only sequence that yields appreciable cross-linking is CpG. N-Methylmitomycin A and its aziridinomitosene are found to be better cross-linking agents than is mitomycin C.

Original languageEnglish (US)
Pages (from-to)3901-3907
Number of pages7
JournalBiochemistry
Volume28
Issue number9
DOIs
StatePublished - May 1989

ASJC Scopus subject areas

  • Biochemistry

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