Supercoil-Accelerated DNA Threading Intercalation

Journal article, 2009

The effect of DNA supercoiling on a sterically very demanding threading intercalation process is here investigated. We find that the threading rate of a dimeric ruthenium complex into a negatively supercoiled plasmid at low binding density is two orders of magnitude higher than into the cleaved linear form. Further saturation is however, in comparison to the linear DNA, kinetically hampered. We also observe that threading kinetics correlates with the inhibition of luciferase expression from the plasmid construct. The results show how the target torsional strain can function as control of DNA threading kinetics and gene expression efficiency.