DNA interstrand cross-links of trans-diamminedichloroplatinum(II) are preferentially formed between guanine and complementary cytosine residues.
basic_science · Level V
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- Record sourced from PubMed, PMID 8506383.
- Also identified by PMC identifier 46713.
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Abstract
Bases in the opposite strands of DNA cross-linked by clinically ineffective trans-diamminedichloroplatinum(II) (trans-[Pt(NH3)2Cl2]) have been identified by means of three experimental approaches. These include HPLC analysis of enzymatic digests of synthetic oligonucleotide duplexes containing the interstrand cross-link, footprinting experiments on the interstrand cross-linked oligonucleotide duplexes, and termination of the duplex transcription on trans-[Pt(NH3)2Cl2]-treated fragments of plasmid DNA. The results reveal that deoxyguanine and complementary deoxycytosine residues are preferential binding sites of trans-[Pt(NH3)2Cl2] in the interstrand adducts. The interstrand cross-linking reaction was studied by means of gel electrophoresis for the cis and trans isomers. The rate of formation of interstrand cross-links was lower for the trans isomer; however, trans-[Pt(NH3)2Cl2] formed about twice the amount of interstrand cross-links as compared with the cis isomer after 48 hr. The present results are suggested to be relevant to differences in clinical activity of the two platinum(II) isomers.
Medical subject headings
- Cisplatin
- Cross-Linking Reagents
- Cytosine
- DNA
- Guanine
- Oligodeoxyribonucleotides