The DNA gyrase was purified from Vibrio cholerae strain 569B. It appeared to be composed of two subunits of Mr 120,000 and 97,000 and had a great deal of similarity to the Escherichia coli gyrase. Unlike the E. coli enzyme, however, it could neither relax supercoiled DNA nor induce a cleavage of double-stranded DNA, under experimental conditions in which E. coli gyrase could do so.
