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Characterization of a human DNA damage binding protein implicated in xeroderma pigmentosum E
1Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720.
The Journal of Biological Chemistry
|October 5, 1993
Summary
Researchers purified a human DNA damage binding protein involved in xeroderma pigmentosum E. This abundant heterodimeric protein recognizes cyclobutane pyrimidine dimers and (6-4) photoproducts in damaged DNA.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Xeroderma pigmentosum E is a DNA excision repair disorder.
- A human DNA damage binding protein is implicated in this disorder.
- Understanding DNA repair mechanisms is crucial for human health.
Purpose of the Study:
- To purify and characterize the human DNA damage binding protein.
- To elucidate the subunit composition and DNA binding properties of the protein.
- To determine the types of DNA lesions recognized by the protein.
Main Methods:
- Purification of the protein from HeLa cells using chromatography.
- Estimation of native molecular weight via gel filtration and glycerol gradient sedimentation.
- Analysis of polypeptide subunits and their association with DNA damage binding activity.
Main Results:
- A heterodimeric protein composed of 124 kDa and 41 kDa subunits was purified.
- The protein exhibits high affinity for damaged DNA, with binding resistant to high salt concentrations.
- The purified protein recognizes both cyclobutane pyrimidine dimers and pyrimidine-pyrimidone (6-4) photoproducts.
Conclusions:
- The purified protein, p124/p41, is a key component in DNA damage recognition.
- Its ability to bind multiple types of DNA lesions suggests a significant role in DNA repair pathways.
- Further studies on this protein may offer insights into xeroderma pigmentosum E and therapeutic strategies.