THE COVALENT BINDING OF ENANTIOMERIC BENZO [A] PYRENE DIOL EPOXIDES TO DOUBLE STRANDED DNA IS STEREOSELECTIVE
Reaction of optically pure (+) and (-) 7{beta},8{alpha}-dihydroxy-9{alpha},10{alpha}-epoxy-7,8,9.10-tetrahydrobenzo[a]pyrene with DNA in vitro yielded diastereomeric covalent adducts with the exocyclic amino groups of deoxyguanosine and deoxyadenosine. The ratio of two deoxyguanosine diastereomers derived by reacting the (+) and (-) hydrocarbons with native calf thymus and double stranded 0X174 DNA was 20:1 while reaction of the enantiomers with heat denatured calf thymus and single stranded 0X174 DNA resulted in a ratio near 1:1. In contrast, deoxyaadenosine diastereomer pairs were approximately 1:1 in all cases studied. The (+) and (-) enantiomers of the benzo[a]pyrene diol epoxide, therefore, interact asymmetrically with the guanine binding sites of double stranded but not single stranded polydeoxynucleotides. In contrast, reaction of the enantiomers with adenine is not stereoselective.
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Physics Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 1014059
- Report Number(s):
- LBL-7956
- Journal Information:
- Science, Journal Name: Science
- Country of Publication:
- United States
- Language:
- English
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