p53 stimulates human topoisomerase I activity by modulating its DNA binding
Related Experiment Video
Updated: Aug 30, 2026

Yeast As a Chassis for Developing Functional Assays to Study Human P53
Published on: August 4, 2019
1Institute of Molecular Biotechnology, Department of Biochemistry, Beutenbergstrasse 11, D-07745 Jena, Germany. kent@imb-jena.de
Abstract:
The tumor suppressor protein p53 and the human DNA topoisomerase I (htopoI) interact with each other, which leads to a stimulation of the catalytic activity of htopoI. Moreover, p53 stimulates the topoisomerase I-induced recombination repair (TIRR) reaction. However, little was known about how p53 stimulates this topoisomerase I activity. Here we demonstrate that monomeric p53 is sufficient for the stimulation of the topoisomerase I-catalyzed relaxation activity, but the tetrameric form of p53 is required for the stimulation of TIRR. We also show that p53 stimulates topoisomerase I activity by increasing the dissociation of htopoI from DNA. Since htopoI forms a closed ring structure around the DNA, our results suggest that p53 induces a conformational change within htopoI that results in an opening of the clamp, and thereby releases htopoI from DNA.
Related Concept Videos
Abnormal Proliferation
DNA Topoisomerases
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
DNA Damage can Stall the Cell Cycle
DNA Damage Can Stall the Cell Cycle
Negative Regulator Molecules
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein.

