The replication initiator operon of promiscuous plasmid RK2 encodes a gene that complements an Escherichia coli mutant defective in single-stranded DNA-binding protein.
The amino acid sequence of the 13-kDa polypeptide (P116) encoded by the first gene of the trfA operon of IncP plasmid RK2 shows significant similarity to several known single-stranded DNA-binding proteins. We found that unregulated expression of this gene from its natural promoter (trfAp) or induced expression from a strong heterologous promoter (trcp) was sufficient to complement the temperature-sensitive growth phenotype of an Escherichia coli ssb-1 mutant. The RK2 ssb gene is the first example of a plasmid single-stranded DNA-binding protein-encoding gene that is coregulated with replication functions, indicating a possible role in plasmid replication.
Jovanovic
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OS
Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
Ayres
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EK
Figurski
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DH
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics*; D001483:Base Sequence; D004261:DNA Replication / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009876:Operon / Q000235:genetics*; D010957:Plasmids / Q000235:genetics*; D011401:Promoter Regions, Genetic / Q000235:genetics; D013696:Temperature
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C075533:SAN protein, E coli