A Novel Secondary DNA Binding Site in Human Topoisomerase I Unravelled by using a 2D DNA Origami Platform

Citations Over TimeTop 13% of 2010 papers

Abstract

The biologically and clinically important nuclear enzyme human topoisomerase I relaxes both positively and negatively supercoiled DNA and binds consequently DNA with supercoils of positive or negative sign with a strong preference over relaxed DNA. One scheme to explain this preference relies on the existence of a secondary DNA binding site in the enzyme facilitating binding to DNA nodes characteristic for plectonemic DNA. Here we demonstrate the ability of human topoisomerase I to induce formation of DNA synapses at protein containing nodes or filaments using atomic force microscopy imaging. By means of a two-dimensional (2D) DNA origami platform, we monitor the interactions between a single human topoisomerase I covalently bound to one DNA fragment and a second DNA fragment protruding from the DNA origami. This novel single molecule origami-based detection scheme provides direct evidence for the existence of a secondary DNA interaction site in human topoisomerase I and lends further credence to the theory of two distinct DNA interaction sites in human topoisomerase I, possibly facilitating binding to DNA nodes characteristic for plectonemic supercoils.

Related Papers

• → The GyrA-box determines the geometry of DNA bound to gyrase and couples DNA binding to the nucleotide cycle(2012)35 cited
• → Changes in Superhelicity Are Introduced into Closed Circular DNA by Binding of High Mobility Group Protein I/Y(1995)94 cited
• → A Role of Basic Residues and the Putative Intercalating Phenylalanine of the HMG-1 Box B in DNA Supercoiling and Binding to Four-way DNA Junctions(2000)46 cited
• → Plasmid DNA Supercoiling by DNA Gyrase(2003)4 cited
• → Protein-induced DNA linking number change by sequence-specific DNA binding proteins and its biological effects(2016)3 cited