DNA sequence preferences for an intercalating porphyin compound revealed by footprinting

Abstract
The DNA sequence preferences of the compound peso -tetra- (4-N-methyl (pyrldyl) porphyrin and Its nickel complex have been Investigated by means of footprinting experiments on several DNA fragments, using DNAase I and nrlcrococcal nuclease as footprinting agents. A complex pattern of both AT and GC-protected sites was found. Ligand-Induced long-range conformational changes were Inferred 1n several Instances to be related to the observed large-scale blockages of enzymatic cutting.