title: Relaxation complexes of plasmids ColE1 and ColE2: unique site of the nick in the open circular DNA of the relaxed complexes.
abstract: The product of the induced relaxation of supercoiled DNA-protein relaxation complexes of colicinogenic factors E1 (ColE1) and E2 (ColE2) is an open circular DNA molecule with a strand-specific nick. Cleavage of the open circular DNA of each relaxed complex with the EcoRI restriction endonuclease demonstrates that the single-strand break is at a unique position. The site of the single-strand break in the relaxed ColE1 complex is approximately the same distance from the EcoRI cleavage site as the origin of ColE1 DNA replication.
mesh_terms: D001665:Binding Sites; D002250:Carbon Radioisotopes; D003087:Colicins / Q000096:biosynthesis; D004269:DNA, Bacterial / Q000032:analysis* / Q000378:metabolism; D004270:DNA, Circular / Q000032:analysis* / Q000378:metabolism; D004720:Endonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000032:analysis*; D005111:Extrachromosomal Inheritance; D009690:Nucleic Acid Conformation; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D003087:Colicins; D004269:DNA, Bacterial; D004270:DNA, Circular; D014316:Tritium; D004720:Endonucleases