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DNA sequence recognition by the antitumor drug ditercalinium
Stephen D G Crow1, Christian Bailly, Christiane Garbay-Jaureguiberry
1Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK.
Biochemistry
|July 3, 2002
Summary
The antitumor drug ditercalinium selectively binds to GC-rich DNA sequences. Guanine's N(7) atom is crucial for this recognition, but its hydrogen-bonding ability alone doesn't explain the selectivity.
Area of Science:
- Medicinal Chemistry
- Molecular Biology
- Drug Discovery
Background:
- Ditercalinium is an antitumor drug that binds noncovalently to DNA via major groove bisintercalation.
- Previous studies focused on short DNA fragments, leaving sequence preferences in longer DNA superficially explored.
Purpose of the Study:
- To investigate the sequence preferences of ditercalinium binding to DNA.
- To identify molecular determinants governing ditercalinium's DNA-binding selectivity.
Main Methods:
- Utilized DNase I footprinting assays on various DNA substrates.
- Employed DNA fragments with natural sequences and unconventional bases (e.g., 7-deazaguanine, N(7)-cyanoboranoguanine).
Main Results:
- Ditercalinium exhibits selective binding to GC-rich DNA sequences.
- The N(7) atom of guanine is essential for sequence-selective binding, while the 2-amino group of purines and 5-methyl group of pyrimidines are not.
- Loss of guanine N(7) significantly reduces ditercalinium's sequence-selective binding.
Conclusions:
- Guanine's N(7) atom plays a critical role in ditercalinium's major groove DNA recognition.
- The hydrogen bond accepting capacity of N(7) is insufficient to fully explain the GC-selective binding.
- Further investigation is needed to understand the precise molecular interactions driving ditercalinium-DNA association.