title: Six amino acids determine the sequence-specific DNA binding and replication specificity of the initiator proteins of the pT181 family.
abstract: The replication of pT181 and related plasmids of Staphylococcus aureus proceeds by a rolling circle mechanisms. The initiator proteins encoded by the plasmids of the pT181 family have sequence-specific DNA binding and topoisomerase activities. These proteins nick one strand of the DNA at the origin of replication. The free 3'-hydroxyl end at the nick is then used as a primer for the replication of the leading strand of the DNA. Although these initiator proteins are highly homologous, they show specificity in DNA binding and replication for their cognate DNAs. In this study, we have generated hybrid initiator proteins and studied their various biochemical activities in vitro. Our results show that 6 amino acids are sufficient to determine the DNA binding and replication specificities of such initiator proteins.
authors.affiliation: Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pennsylvania 15261.
authors.forename: L A
authors.initials: LA
authors.lastname: Dempsey
authors.forename: P
authors.initials: P
authors.lastname: Birch
authors.forename: S A
authors.initials: SA
authors.lastname: Khan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003001:Cloning, Molecular; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010957:Plasmids; D012097:Repressor Proteins / Q000378:metabolism; D013211:Staphylococcus aureus / Q000235:genetics* / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D009838:Oligodeoxyribonucleotides; C043650:RepC protein, Staphylococcus aureus; C058757:RepD protein, Staphylococcus aureus; C074164:RepE protein, E coli; D012097:Repressor Proteins