FIG. 1.

Detection of V. vulnificus nuclease in the periplasm of E. coli recombinant clones. Proteins in the periplasm were fractionated by SDS-PAGE, and the gel (12.5%) was visualized by Coomassie blue staining (left). A duplicate of the gel was renatured and overlaid on an agarose gel containing DNA and ethidium bromide for 4 h. Bands with DNase activity were visualized by placing the agarose gel on a UV box (right). Lanes: M, molecular weight standards indicated in kilodaltons; 1, periplasmic fraction of E. coli DH5α(pUC19), undiluted; 2, periplasmic fraction of DH5α(pSI014), undiluted; 3, periplasmic fraction of DH5α(pSI014), twofold diluted. pSI014 was a pUC19 derivative containing the vvn gene. The position of V. vulnificus nuclease is indicated by an arrowhead.