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Base specific complex formation of norfloxacin with DNA
1Department of Chemistry, College of Sciences, Yeungnam University, Kyoungsan City, South Korea.
Biophysical Chemistry
|October 21, 1998
Summary
Norfloxacin preferentially binds to guanine-cytosine bases in DNA, interacting with purines more than pyrimidines. Spectroscopic analysis indicates a perpendicular binding orientation, ruling out groove or surface binding.
Area of Science:
- Molecular Biology
- Biochemistry
- Drug Interactions
Background:
- Norfloxacin is a fluoroquinolone antibiotic with known DNA gyrase inhibitory activity.
- Understanding the specific interactions between antibiotics and DNA is crucial for developing effective antimicrobial therapies.
Purpose of the Study:
- To elucidate the base specificity and binding mode of norfloxacin with DNA.
- To investigate the interaction of norfloxacin with different DNA base compositions.
Main Methods:
- Binding constants were determined using the Stern-Volmer and Benesi-Hildebrand methods with synthetic polynucleotides.
- Circular dichroism (CD) and linear dichroism (LD) were employed to study the binding mode.
Main Results:
- Norfloxacin exhibited the highest binding affinity for GC-rich polynucleotides (poly[d(G-C)2] and poly(dG).poly(dC)).
- Norfloxacin demonstrated a greater affinity for purine bases compared to pyrimidine bases.
- CD and LD spectra indicated a perpendicular orientation of norfloxacin relative to the DNA helix axis, excluding groove or surface binding.
Conclusions:
- Norfloxacin displays a preference for guanine-cytosine rich regions in DNA.
- The binding mode is characterized by a perpendicular orientation of the drug molecule to the DNA helix, suggesting intercalation or a related mechanism.