Publication details

Differential Salt-Induced Dissociation of the p53 Protein Complexes with Circular and Linear Plasmid DNA Substrates Suggest Involvement of a Sliding Mechanism

Authors

ŠEBEST Peter BRÁZDOVÁ Marie FOJTA Miroslav PIVOŇKOVÁ Hana

Year of publication 2015
Type Article in Periodical
Magazine / Source International Journal of Molecular Sciences
MU Faculty or unit

Central European Institute of Technology

Citation
Web http://www.mdpi.com/1422-0067/16/2/3163/htm
Doi http://dx.doi.org/10.3390/ijms16023163
Field Biochemistry
Keywords TUMOR-SUPPRESSOR P53; CISPLATIN-DAMAGED DNA; SUPERCOILED DNA; MERCURY-ELECTRODE; BINDING; CONFORMATION; SPECIFICITY; KINETICS; DOMAINS; SEARCH
Attached files
Description A study of the effects of salt conditions on the association and dissociation of wild type p53 with different ~3 kbp long plasmid DNA substrates (supercoiled, relaxed circular and linear, containing or lacking a specific p53 binding site, p53CON) using immunoprecipitation at magnetic beads is presented. Salt concentrations above 200 mM strongly affected association of the p53 protein to any plasmid DNA substrate. Strikingly different behavior was observed when dissociation of pre-formed p53-DNA complexes in increased salt concentrations was studied. While contribution from the p53CON to the stability of the p53-DNA complexes was detected between 100 and 170 mM KCl, p53 complexes with circular DNAs (but not linear) exhibited considerable resistance towards salt treatment for KCl concentrations as high as 2 M provided that the p53 basic C-terminal DNA binding site (CTDBS) was available for DNA binding. On the contrary, when the CTDBS was blocked by antibody used for immunoprecipitation, all p53-DNA complexes were completely dissociated from the p53 protein in KCl concentrations >= 200 mM under the same conditions. These observations suggest: (a) different ways for association and dissociation of the p53-DNA complexes in the presence of the CTDBS; and (b) a critical role for a sliding mechanism, mediated by the C-terminal domain, in the dissociation process.
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