Escherichia coli DNA polymerase II is stimulated by DNA polymerase III holoenzyme auxiliary subunits

A. John Hughes, Sharon K. Bryan, Hong Chen, Robb Moses, Charles S. McHenry

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Abstract

DNA polymerase III of Escherichia coli requires multiple auxiliary factors to enable it to serve as a replicative complex. We demonstrate that auxiliary components of the DNA polymerase III holoenzyme, the γδ complex and β subunit, markedly stimulate DNA polymerase II on long single-stranded templates. DNA polymerase II activity is enhanced by single-stranded DNA binding protein, but the stimulation by γδ and β can be observed either in the absence or presence of single-stranded DNA binding protein. In contrast with DNA polymerase III, the requirement of DNA polymerase II for γδ cannot be bypassed by large excesses of the β subunit at low ionic strength in the absence of the single-stranded DNA binding protein. The product of the DNA polymerase II-γδ-β reaction on a uniquely primed single-stranded circle is of full template length; the reconstituted enzyme apparently is incapable of strand displacement synthesis. The possible biological implications of these observations are discussed.

Original languageEnglish (US)
Pages (from-to)4568-4573
Number of pages6
JournalJournal of Biological Chemistry
Volume266
Issue number7
Publication statusPublished - Mar 5 1991
Externally publishedYes

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ASJC Scopus subject areas

  • Biochemistry

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