Interactions of the DNA Polymerase X of African Swine Fever Virus with Double-stranded DNA. Functional Structure of the Complex

Maria J. Jezewska, Paul J. Bujalowski, Wlodzimierz Bujalowski

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


Interactions of the polymerase X of African swine fever virus with the double-stranded DNA (dsDNA) have been studied with fluorescent dsDNA oligomers, using quantitative fluorescence titrations, analytical ultracentrifugation, and fluorescence energy transfer techniques. Studies with unmodified dsDNAs were performed, using competition titration method. ASV pol X binds the dsDNA with a site-size of n = 10(±2) base-pairs, which is significantly shorter than the total site-size of 16(±2) nucleotides of the enzyme-ssDNA complex. The small site size indicates that the enzyme binds the dsDNA exclusively using the proper DNA-binding subsite. Fluorescence energy transfer studies between the tryptophan residue W92 and the acceptor, located at the 5′ or 3′ end of the dsDNA, suggest strongly that the proper DNA-binding subsite is located on the non-catalytic C-terminal domain. Moreover, intrinsic interactions with the dsDNA 10-mer or 20-mer are accompanied by the same net number of ions released, independent of the length of the DNA, indicating the same length of the DNA engaged in the complex. The dsDNA intrinsic affinity is about two orders of magnitude higher than the ssDNA affinity, indicating that the proper DNA-binding subsite is, in fact, the specific dsDNA-binding site. Surprisingly, ASFV pol X binds the dsDNA with significant positive cooperativity, which results from protein-protein interactions. Cooperative interactions are accompanied by the net ion release, with anions participating in the ion-exchange process. The significance of these results for ASFV pol X activity in the recognition of damaged DNA is discussed.

Original languageEnglish (US)
Pages (from-to)75-95
Number of pages21
JournalJournal of Molecular Biology
Issue number1
StatePublished - Oct 12 2007
Externally publishedYes


  • DNA polymerases
  • DNA repair
  • DNA replication
  • protein-DNA interactions
  • quantitative fluorescence titrations

ASJC Scopus subject areas

  • Molecular Biology
  • Biophysics
  • Structural Biology


Dive into the research topics of 'Interactions of the DNA Polymerase X of African Swine Fever Virus with Double-stranded DNA. Functional Structure of the Complex'. Together they form a unique fingerprint.

Cite this