Nonspecific endonucleases involved in DNA repair can scan DNA for target sequences or damage. Such a nuclease diffuses along DNA until it encounters a target, upon which the residues of its active site interact with the chemical groups of the DNA. In the case of endonucleases such as EcoRV, BamHI, and PvuII, this nonspecific binding involves electrostatic interactions between minimal surface area of the protein and the DNA. This weak association leaves the overall shape of the DNA undeformed, remaining in B-form.