The Regulatory Function of N-terminal AAA+ ATPase Domain of Eukaryote-Like Archaeal Orc1/Cdc6 Protein During DNA Replication Initiation

Arch Biochem Biophys. 2008 Mar 15;471(2):176-83. doi: 10.1016/ Epub 2008 Jan 19.


Archaeal replication machinery represents a core version of this in eukaryotes. The crenarchaeon Sulfolobus solfataricus has the potential to be a powerful model system to understand the central mechanism of eukaryotic DNA replication because it contains three active origins of replication and three eukaryote-like Orc1/Cdc6 proteins (SsoCdc6-1, SsoCdc6-2, and SsoCdc6-3). In this study, we investigate the DNA-binding activities of the N-terminal AAA+ ATPase domains of these Orc1/Cdc6 proteins, including their functional interactions with the other SsoCdc6 proteins, on duplex DNA substrates derived from the origins of S. solfataricus. We showed that the ATPase domain of SsoCdc6-2 retained to a great extent the origin DNA-binding activity, and likewise maintained its stimulating effect on SsoCdc6-3. Second, the ATPase domain of SsoCdc6-1, which also stimulated the DNA-binding ability of SsoCdc6-3, demonstrated a significantly improved DNA-binding activity at the forked substrate, but only showed a very weak ability towards the blunt DNA. Third, the ATPase domain of SsoCdc6-3, although having lost much of its DNA-binding activity from the origin, inhibited both SsoCdc6-1 and SsoCdc6-2. These imply that the N-terminal AAA+ ATPase domain of archaeal Orc1/Cdc6 protein could be differentially involved in origin recognition during DNA replication initiation even if lacking conventional C-terminal winged helix DNA-binding elements. Our findings further propose that conserved AAA+ ATPase domains of Orc1/Cdc6 proteins determine their defined and coordinated functions not only in the archaeon species but also in eukaryotes during the early events of DNA replication.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics
  • Adenosine Triphosphatases / metabolism*
  • Archaeal Proteins / chemistry
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism*
  • Base Sequence
  • DNA Replication / genetics
  • DNA Replication / physiology*
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Electrophoretic Mobility Shift Assay
  • Eukaryotic Cells / chemistry
  • Molecular Sequence Data
  • Origin Recognition Complex / chemistry
  • Origin Recognition Complex / genetics
  • Origin Recognition Complex / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Replication Origin / genetics
  • Replication Origin / physiology
  • Sulfolobus solfataricus / enzymology*
  • Sulfolobus solfataricus / genetics


  • Archaeal Proteins
  • DNA-Binding Proteins
  • Origin Recognition Complex
  • Adenosine Triphosphatases