Direct physical interaction between DnaG primase and DnaB helicase of Escherichia coli is necessary for optimal synthesis of primer RNA.
The primase DnaG of Escherichia coli requires the participation of the replicative helicase DnaB for optimal synthesis of primer RNA for lagging strand replication. However, previous studies had not determined whether the activation of the primase or its loading on the template was accomplished by a helicase-mediated structural alteration of the single-stranded DNA or by a direct physical interaction between the DnaB and the DnaG proteins. In this paper we present evidence supporting direct interaction between the two proteins. We have mapped the surfaces of interaction on both DnaG and DnaB and show further that mutations that reduce the physical interation also cause a significant reduction in primer synthesis. Thus, the physical interaction reported here appears to be physiologically significant.
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Department of Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
Ratnakar
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Mohanty
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BK
Bastia
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D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001665:Binding Sites; D004265:DNA Helicases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D019915:DNA Primase; D004261:DNA Replication; D053488:DnaB Helicases; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016366:Open Reading Frames; D017354:Point Mutation; D011485:Protein Binding; D014176:Protein Biosynthesis; D012313:RNA / Q000096:biosynthesis; D012316:RNA Nucleotidyltransferases / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D012329:RNA, Bacterial / Q000096:biosynthesis*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D014158:Transcription, Genetic
D001426:Bacterial Proteins; C034477:RNA primers; D012329:RNA, Bacterial; D011994:Recombinant Proteins; D012313:RNA; D019915:DNA Primase; D012316:RNA Nucleotidyltransferases; D004265:DNA Helicases; D053488:DnaB Helicases