Unwinding of the Escherichia coli origin of replication (oriC) can occur in the absence of initiation proteins but is stabilized by DnaA and histone- like proteins IHF or HU

Piotr Polaczek, Kelvin Kwan, Judith L. Campbell

Research output: Contribution to journalArticle

11 Scopus citations

Abstract

The unwinding of the origin of replication (oriC) is a critical step in initiation of DNA replication in Escherichia coli. Previous observations indicate that efficient unwinding of supercoiled plasmid templates containing oriC sequences requires the DnaA initiation protein and one or more accessory factors. The precise contribution of each protein to this process is unknown. Here, we demonstrate that unwinding can occur under physiological conditions at the same bases in oriC, in either the presence or the absence of initiation proteins, as detected by a single-strand specific nuclease, PI. This suggests that oriC unwinding is a spontaneous event determined solely by DNA sequence. DnaA and IHF, as part of a large nucleoprotein complex, may function to stabilize the DNA strand opening prior to initiation of DNA replication.

Original languageEnglish (US)
Pages (from-to)77-83
Number of pages7
JournalPlasmid
Volume39
Issue number1
DOIs
StatePublished - Jan 1998
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology

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