DNA unwinding component of the nonhistone chromatin proteins
A subclass of nonhistone chromatin proteins from rat liver, previously shown to exhibit high affinity for DNA, has been fractionated by single-stranded DNA-agarose affinity chromatography. The protein fraction that bound to DNA-agarose in 0.19 M NaCl-buffer and was eluted with 2 M NaCl-buffer is enriched for a protein component of approximately 20,000 daltons and exhibits preferential binding to denatured DNA. This nonhistone protein fraction specific for single strands binds to DNA in a non-species-specific manner, and causes helix-coil transition of synthetic poly(d(A-T).d(A-T)) at 25/sup 0/, as indicated by the increase in absorbance of ultraviolet light at 260 nm. The observed hyperchromicity does not result from any nuclease activity in the protein fraction, because addition of Mg/sup +2/ results in partial hypochromic shift, and the protein/DNA complex is retained by nitrocellulose filters.
- Research Organization:
- Univ. of Georgia, Athens, GA (United States)
- DOE Contract Number:
- E(38-1)-644
- OSTI ID:
- 7327990
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 73:12
- Country of Publication:
- United States
- Language:
- English
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