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Updated: Jan 20, 2026
09:33
Formation of Covalent DNA Adducts by Enzymatically Activated Carcinogens and Drugs In Vitro and Their Determination by 32P-postlabeling
Published on: March 20, 2018
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Molecular Structure of Binary Chromium(III)-DNA Adducts
Silas Brown1, Molly M Lockart1, C Sumner Thomas1
1The University of Alabama, Department of Chemistry and Biochemistry, Box 870336, 250 Hackberry Lane, Tuscaloosa, AL, 43587-0336, USA.
Chembiochem : a European Journal of Chemical Biology
|September 1, 2019
Summary
Chromium(III) binds to DNA exclusively at guanine N7 positions. This study clarifies the molecular interactions of chromium(III) with DNA, crucial for understanding chromium carcinogenicity.
Area of Science:
- Environmental Toxicology
- Molecular Biology
- Biochemistry
Background:
- Chromium(VI) is a known carcinogen and mutagen.
- Its genotoxic effects are hypothesized to stem from its reduction product, chromium(III), binding to DNA.
- The precise molecular interactions of chromium(III) with DNA remain poorly understood.
Purpose of the Study:
- To elucidate the molecular-level binding site of chromium(III) on DNA.
- To investigate the interaction specificity of chromium(III) with DNA bases and backbone.
Main Methods:
- Analysis of oligonucleotide duplex DNA using Nuclear Magnetic Resonance (NMR) spectroscopy.
- Electron Paramagnetic Resonance (EPR) spectroscopy to study chromium interactions.
- Infrared (IR) spectroscopy to probe molecular binding.
Main Results:
- Chromium(III) metal centers exclusively interact with the N7 position of guanine residues.
- No evidence was found for chromium interactions with other DNA bases (adenine, cytosine, thymine).
- No interactions with the DNA backbone phosphates or formation of intra-strand crosslinks between guanine residues were observed.
Conclusions:
- The binding of chromium(III) to DNA is specific to the guanine N7 position.
- This finding provides a molecular basis for understanding the mechanisms of chromium-induced DNA damage and mutagenicity.
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