title: The action of colicin E2 on supercoiled lambda DNA.II. Experiments in vitro.
abstract: An in vitro system has been developed to test whether colicin E2 possesses DNase activity. Purified colicin E2 preparations introduced one single-strand scission in supercoiled lambda phage DNA. Glycerol gradient fractionation of colicin E2 supports the association of in vitro action with in vivo cell-killing activity. Colicin E2 preparations also attacked superhelical SV40 DNA yielding open circles and fragments and single-stranded fd DNA molecules causing one or more endonucleolytic breaks. The possible role of contaminating nucleases in the activity of colicin E2 preparations is discussed.
mesh_terms: D001665:Binding Sites; D002499:Centrifugation, Density Gradient; D002852:Chromatography, Ion Exchange; D003087:Colicins / Q000302:isolation & purification; D003090:Coliphages; D004279:DNA, Viral; D004720:Endonucleases; D009154:Mutation; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D013539:Simian virus 40; D013045:Species Specificity
chemical_list: D003087:Colicins; D004279:DNA, Viral; D004720:Endonucleases