Two structurally related diaziridinylbenzoquinones preferentially cross-link DNA at different sites upon reduction with DT-diaphorase.
The nucleotide sequence preferences for the formation of interstrand cross-links induced in DNA by 2,5-diaziridinyl-1,4-benzoquinone (DZQ) and 3,6-dimethyl-2,5-diaziridinyl-1,4-benzoquinone (MeDZQ) were studied using synthetic duplex oligonucleotides and denaturing polyacrylamide gel electrophoresis (PAGE). Reaction of these bifunctional alkylating agents with a DNA duplex containing several potential cross-linking sites resulted in the formation of cross-linked DNAs with different electrophoretic mobilities. Analysis of the principal cross-linked products by piperidine fragmentation revealed that the preferential site of cross-linking was altered from a 5'-GNC to a 5'-GC sequence upon reduction of DZQ to the hydroquinone form by the enzyme DT-diaphorase. In contrast, the reduced form of MeDZQ was found to preferentially cross-link at 5'-GNC sites within the same sequence. These preferences were confirmed in duplex oligonucleotides containing single potential cross-linking sites. Additional minor cross-linked products were characterized and revealed that DZQ and MeDZQ are both capable of cross-linking across four base pairs in a 5'-GNNC sequence.
Berardini
M D
MD
Department of Oncology, University College & Middlesex School of Medicine, London, U.K.
Souhami
R L
RL
Lee
C S
CS
Gibson
N W
NW
Butler
J
J
Hartley
J A
JA
D000478:Alkylation; D001388:Aziridines / Q000737:chemistry*; D001483:Base Sequence; D016227:Benzoquinones / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry*; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry; D008969:Molecular Sequence Data; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D010084:Oxidation-Reduction
D001388:Aziridines; D016227:Benzoquinones; D003432:Cross-Linking Reagents; D009838:Oligodeoxyribonucleotides; C073715:2,5-dimethyl-3,6-diaziridinyl-1,4-benzoquinone; D006147:Guanine; D004247:DNA; D016660:NAD(P)H Dehydrogenase (Quinone); C029108:diaziquone