RNA polymerases react differently at d(ApG) and d(GpG) adducts in DNA modified by cis-diamminedichloroplatinum(II)
- Centre National de la Recherche Scientifique, Marseille (France)
- Centre National de la Recherche Scientifique, Orleans (France)
Two duplexes (20-mers) were constructed containing either a single cis-(Pt(NH{sub 3}){sub 2}(d(GpG))) or cis-(Pt(NH{sub 3}){sub 2}(d(ApG))) intrastrand cross-link, the major DNA adducts of the antitumor drug cis-diamminedichloroplatinum(II). These synthetic duplexes were multimerized and the resultant polymers used as templates in single-step addition reactions of condensation of a single nucleoside triphosphate substrate to a dinucleotide primer (abortive elongation reaction) catalyzed by prokaryotic or eukaryotic RNA polymerases. Primer-substrate combinations were selected so as to direct trinucleotide product formation within the platinated bases of the templates. Transcription experiments established that cis-DDP-DNA adducts formed at d(ApG) or d(GpG) sites are not an absolute block to formation of a single phosphodiester bond by either Escherichia coli RNA polymerase or wheat germ RNA polymerase II. Furthermore, the kinetic data indicate that single-step addition reactions are much more impeded at the platinated d(GpG) than at the platinated d(ApG) site and that the mechanisms of inhibition of RNA polymerase activity are different at the two platinated sites. In particular, binding affinity between E. coli RNA polymerase and the d(GpG)-containing platinated template is lowered, as the apparent K{sub m} of enzyme for the platinated polymer is increased by a factor of 4-5. These results are discussed in reaction to the distortions induced in DNA by the two adducts.
- OSTI ID:
- 5598860
- Journal Information:
- Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 31:7; ISSN 0006-2960; ISSN BICHA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Transcription by eucaryotic and procaryotic RNA polymerases of DNA modified at a d(GG) or a d(AG) site by the antitumor drug cis-diamminedichloroplatinum (II)
DNA unwinding produced by site-specific intrastrand cross-links of the antitumor drug cis-diamminedichloroplatinum(II)
Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADDUCTS
BACTERIA
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
DNA ADDUCTS
ENZYMES
ESCHERICHIA COLI
KINETICS
MICROORGANISMS
MOLECULAR BIOLOGY
NUCLEIC ACIDS
NUCLEOTIDYLTRANSFERASES
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PLATINUM COMPOUNDS
POLYMERASES
PROTEINS
REACTION KINETICS
RNA POLYMERASES
TRANSCRIPTION
TRANSFERASES
TRANSITION ELEMENT COMPOUNDS