Cleavage and circularization of single-stranded DNA: a novel enzymatic activity ofφX174 A*protein

Abstract
Purified ØX gene A* protein cleaves ØX single stranded DNA. The cleavage appears to be stoichiometric, whereby a gene A* protein molecule cleaves a phosphodiester bond and binds to the DNA fragment. The size of the cleavage product was inversely proportional to the ratio of A* protein to DNA in the reaction mixture.