The strong binding of luzopeptin to DNA

The effect of luzopeptin on the mobility of DNA in polyacrylamide gels has been determined. Experiments on a mixture of DNA fragments of various lengths have shown that the drug does not form intermolecular cross-links. Gel analysis of complexes of the drug with short DNA fragments (15-35 base pairs) reveals a ladder of discrete bands in which each band appears to correspond to the addition of a further drug molecule. The results suggest that luzopeptin binds very strongly to DNA, occupying about four base pairs and displays little or no sequence selectivity. Luzopeptin renders certain adenine residues hyperreactive to diethylpyrocarbonate, these occur in different positions to those affected by echinomycin.