title: Enzymatic properties of the bacteriophage phi X174 A protein on superhelical phi X174 DNA: a model for the termination of the rolling circle DNA replication.
abstract: Incubation of phi X174 replication form I DNA with the A* protein of phi X174 in the presence of MN2+ results in the formation of three different types of DNA molecules: open circular form DNA (RFII), linear form DNA (RFIII) and the relaxed covalently closed form DNA (RFIV). The RFII and RFIII DNAs are shown to be A* protein-DNA complexes by electron microscopy using the protein labeling technique of Wu and Davidson (1). The linear double-stranded RFIII DNA molecule carries at one end a covalently attached A* protein whereas at the other end of the molecule the single-stranded termini are covalently linked to each other. The structure of the RFIII DNA shows its way of formation. The described properties of the A* protein indicate the way the larger A protein functions in the termination step of the rolling-circle type of phi X174 DNA replication.
mesh_terms: D010584:Bacteriophage phi X 174 / Q000201:enzymology*; D001483:Base Sequence; D004261:DNA Replication; D004262:DNA Restriction Enzymes; D004270:DNA, Circular / Q000378:metabolism; D004278:DNA, Superhelical / Q000378:metabolism*; D004279:DNA, Viral / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D008345:Manganese / Q000494:pharmacology; D008854:Microscopy, Electron; D009691:Nucleic Acid Denaturation; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D004270:DNA, Circular; D004278:DNA, Superhelical; D004279:DNA, Viral; D014764:Viral Proteins; D008345:Manganese; D003851:Deoxyribonucleases; D004262:DNA Restriction Enzymes