Participation of the fingers subdomain of Escherichia coli DNA polymerase I in the strand displacement synthesis of DNA

Kamalendra Singh, Aashish Srivastava, Smita S. Patel, Mukund J. Modak

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

The replication of the genome requires the removal of RNA primers from the Okazaki fragments and their replacement by DNA. In prokaryotes, this process is completed by DNA polymerase I by means of strand displacement DNA synthesis and 5′-nuclease activity. Here, we demonstrate that the strand displacement DNA synthesis is facilitated by the collective participation of Ser 769, Phe771, and Arg841 present in the fingers subdomain of DNA polymerase I. The steady and presteady state kinetic analysis of the properties of appropriate mutant enzymes suggest that: (a) Ser 769 and Phe771 together are involved in the strand separation via the formation of a flap structure, and (b) Arg841 interacts with the template strand to achieve the optimal strand separation and DNA synthesis. The amino acid residues Ser769 and Phe771 are constituents of the O1-helix, which together with O and O2 helices form a 3-helix bundle structure. We note that this 3-helix bundle motif also exists in prokaryotic RNA polymerase. Thus in both DNA and RNA polymerases, this motif may have been adopted to achieve the strand separation function.

Original languageEnglish (US)
Pages (from-to)10594-10604
Number of pages11
JournalJournal of Biological Chemistry
Volume282
Issue number14
DOIs
StatePublished - Apr 6 2007

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'Participation of the fingers subdomain of Escherichia coli DNA polymerase I in the strand displacement synthesis of DNA'. Together they form a unique fingerprint.

Cite this