Ultraviolet-Laser Footprinting

A large number of processes within the cell, in particular the regulation of gene expression, rely on the binding of proteins to specific sites on the DNA. A primary ingredient to understanding these processes is the characterization of the protein-DNA interaction (1 ). Such a characterization consists in determining the position of the binding site on the DNA and measuring the affinity of the protein for this recognition site. A wide variety of footprinting techniques can accomplish this task (2 ,3 ).