Related Experiment Videos
Oxidative charge transport through DNA in nucleosome core particles
Megan E Núñez1, Katherine T Noyes, Jacqueline K Barton
1Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
Chemistry & Biology
|May 2, 2002
Summary
DNA charge transport occurs even within nucleosomes, the protein-DNA packaging units. Histone proteins do not prevent this oxidative damage, indicating DNA is vulnerable to charge transfer within cells.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Eukaryotic DNA is organized into nucleosomes, with DNA wrapped around histone proteins.
- Nucleosome structure generally protects DNA from external damaging agents.
- Understanding DNA charge transport is crucial for comprehending DNA stability and repair.
Purpose of the Study:
- To investigate DNA charge transport within nucleosome assemblies.
- To determine if histone proteins affect DNA oxidative damage via charge transport.
- To explore the vulnerability of packaged DNA to charge transfer.
Main Methods:
- Utilized photoexcited rhodium intercalators to probe DNA charge transport.
- Examined oxidation of guanine bases (5'-GG-3') as a signature of charge transport.
- Employed rhodium intercalators tethered to DNA termini to assess long-range transport.
Main Results:
- Histone proteins inhibited rhodium complex intercalation but not 5'-GG-3' oxidation.
- Guanine bases within nucleosomes were oxidized from a distance of 24 bp.
- Histone binding did not alter the pattern or extent of DNA oxidation.
Conclusions:
- Nucleosome packaging does not prevent DNA charge transport.
- DNA within nucleosomes is susceptible to charge transfer damage.
- Histone proteins do not shield DNA from oxidative damage mediated by charge transport.