Threading intercalators bind DNA with high affinities. Here, we describe single-molecule studies on a cell-permeant luminescent dinuclear ruthenium(II) complex that has been previously shown to thread only into short, unstable duplex structures. Using optical tweezers and confocal microscopy, show this threads locks force-extended in two-step mechanism. Detailed kinetic reveal an individual ste...

Platinum-based anticancer drugs act therapeutically by forming DNA adducts, but suffer from severe toxicity and resistance problems, which have not been overcome in spite of decades of research. And yet defined chromatin targets have generally not been considered in the drug development process. Here we designed novel platinum-intercalator species to target a highly deformed DNA site near the n...

Bis(chlorotetrylene)s of Si, Ge, and Sn have been synthetically realized starting from the backbone-bridged bis(amidine) 1. Double deprotonation 1 subsequent reaction with trichlorosilane affords bis(dichorosilane) 2, which is converted to respective bis(chlorosilylene) 3 by dehydrochlorination using lithium bis(trimethylsilyl)amide. The related bis(chlorogermylene) 4 bis(chlorostannylene) 5 ar...

Exonuclease III has been shown previously to reveal the binding sites of the antitumor drug cis-diamminedichloroplatinum(II) on DNA. Pretreatment of the same DNA with the intercalator ethidium bromide causes new platinum binding sites to be detected by the exonuclease III method. In particular, a 5'd(G6-D-G2)3' sequence in a 165-base-pair restriction fragment of plasmid pBR322 becomes a preferr...

DNA stretching in the nucleosome core can cause dramatic structural distortions, which may influence compaction and factor recognition in chromatin. We find that the base pair unstacking arising from stretching-induced extreme minor groove kinking near the nucleosome centre creates a hot spot for intercalation and alkylation by a novel anticancer compound. This may have far reaching implication...