Conformational study of the binding of a high mobility group protein with chromatin
The nature of the binding of a high mobility group protein (HMG 17) to native and H1-H5-depleted chicken erythrocyte chromatin was studied, as a function of ionic strength, using circular dichroism and thermal denaturation techniques. The circular dichroism properties of the HMG 17-reconstituted whole chromatin and H1-H5-depleted chromatin structure occurred upon HMG 17 binding at low ionic strength. Thermal denaturation profiles confirmed this change in the structure of chromatin induced by HMG 17. Thermal denaturation profiles were resolved into three-component transitions. These results indicate that the binding sites of HMG 17 are situated in the linker regions immediately adjacent to the core. The nature of the interaction of HMG 17 at higher ionic strength with whole chromatin and H1-H5-depleted chromatin was found to be different. These observations suggest that HMG 17 does not loosen chromatin structure but produces an overall stabilization and condensation of structure. The implications of these results to the currently accepted models of transcriptionally active chromatin are discussed.
- Research Organization:
- Brandeis Univ., Waltham, MA
- DOE Contract Number:
- AC02-78EV04962
- OSTI ID:
- 5128181
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 257:19
- Country of Publication:
- United States
- Language:
- English
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