摘要：Dihydropyrazine (DHP), which induces mutagenesis in E. coli , was investigated. From analyzing mutations in the chromosomal rpoB gene, the mutation spectrum in uvrB strain revealed the different behavior on exposure to two DHP derivatives 3-hydro-2,2,5,6-tetramethylpyrazine (HTMP), and 2,3-dihydro-5,6-dimethylpyrazine (DHDMP). A higher level of DHP-induced mutation was observed, with base substitutions at G : C pairs predominant. HTMP and DHDMP increased the frequency of G : C to T : A transversions. HTMP increased the frequency of G : C to A : T transitions, than did DHDMP. These findings suggest that DHPs prefer to attack the G : C pair and that different DHP derivatives may prefer distinct mutagenic base pairs; and further, that nucleotide excision repair may be involved in the repair of DHP-induced mutations.
