title: Origin of replication of colicin E1 plasmid DNA.
abstract: Cleavage maps of colicin E1 plasmid DNA and its smaller derivative, pNT1 DNA, were constructed by using restriction endonucleases. The nucleotide sequence of a region that contains the orgin of replication was determined. The site of the nucleotide from which DNA replication is initiated was determined with 6S L-fragments, the DNA fragment first made on colicin E1 plasmid DNA. The fragments were labeled with [gamma-32P]ATP and polynucleotide 5'-hydroxyl-kinase (ATP:5'-dephosphopolynucleotide 5'-phosphotransferase, EC 2.7.1.78) at the 5'-OH groups which were uncovered by alkali treatment. The site is one of three consecutive nucleotides, dA, dA, and dC, located at a unique position. One or a few rA residues were found to be attached to some of the DNA molecules. The transition from the primer RNA to DNA occurs in a region consisting of a segment of five A residues. Both sides of this segment are rich in G and C.
mesh_terms: D001483:Base Sequence; D003087:Colicins; D004261:DNA Replication; D004262:DNA Restriction Enzymes; D004269:DNA, Bacterial / Q000096:biosynthesis*; D004926:Escherichia coli / Q000378:metabolism; D005111:Extrachromosomal Inheritance; D010957:Plasmids
chemical_list: D003087:Colicins; D004269:DNA, Bacterial; D004262:DNA Restriction Enzymes