Binding of beryllium to nuclear acidic proteins
Chemico-Biological Interactions
|July 1, 1979
Summary
Beryllium (Be) binds to rat liver nuclei and nucleoli. This toxic metal strongly associates with specific non-histone proteins and DNA-bound fractions in chromatin, not histones.
Area of Science:
- Biochemistry
- Toxicology
- Cell Biology
Background:
- Beryllium (Be) is a toxic metal with known biological effects.
- Understanding its interaction with cellular components is crucial for toxicology and cell biology.
- Previous studies on Be binding to cellular components require reassessment.
Purpose of the Study:
- To reassess the in vitro binding of beryllium to rat liver nuclei and nucleoli.
- To investigate the specific binding sites of beryllium within rat liver chromatin fractions.
- To explore the relationship between beryllium binding and protein phosphorylation.
Main Methods:
- In vitro binding assays using rat liver nuclei and nucleoli.
- Chromatographic fractionation of rat liver chromatin on a hydroxyapatite column.
- Analysis of beryllium binding to different protein and DNA fractions.
Main Results:
- Beryllium exhibits significant binding to rat liver nuclei (KAss = 2.0 X 10(6) M) and nucleoli (KAss ≈ 4 X 10(6) M).
- Beryllium does not bind to histones or to non-histone proteins eluted by 0.05 M sodium phosphate.
- Strong beryllium binding occurs with non-histone proteins (KAss = 1.1 X 10(6) M) and DNA-containing fractions eluted by 0.2 M sodium phosphate, with evidence suggesting binding is not to DNA itself.
- Beryllium-binding protein fractions are also highly phosphorylated.
Conclusions:
- Beryllium preferentially binds to specific non-histone proteins and DNA-associated fractions within rat liver chromatin.
- The observed binding patterns suggest a potential role for these fractions in beryllium toxicity.
- Further research is warranted to elucidate the functional implications of beryllium's interaction with phosphorylated proteins in chromatin.
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