Real-time investigation of SV40 large T-antigen helicase activity using surface plasmon resonance

Cell Biochem Biophys. 2009;53(1):43-52. doi: 10.1007/s12013-008-9038-z. Epub 2008 Dec 2.


The simian virus 40 (SV40) genome is a model system frequently employed for investigating eukaryotic replication. Large T-antigen (T-ag) is a viral protein responsible for unwinding the SV40 genome and recruiting necessary host factors prior to replication. In addition to duplex unwinding T-ag possesses G-quadruplex DNA helicase activity, the physiological consequence of which is unclear. However, formation of G-quadruplex DNA structures may be involved in genome maintenance and function, and helicase activity to resolve these structures may be necessary for efficient replication. We report the first real-time investigation of SV40 T-ag helicase activity using surface plasmon resonance (SPR). In the presence of ATP, T-ag was observed to bind to immobilized single-stranded DNA, forked duplex DNA, and the human telomeric foldover quadruplex DNA sequence. Inhibition of T-ag duplex helicase activity was observable in real-time and the intramolecular quadruplex was unwound.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / metabolism
  • Antigens, Viral, Tumor / genetics
  • Antigens, Viral, Tumor / metabolism*
  • DNA Helicases / genetics
  • DNA Helicases / metabolism*
  • DNA Replication / genetics
  • DNA Replication / immunology
  • DNA, Viral / genetics*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • G-Quadruplexes
  • Humans
  • Simian virus 40 / enzymology*
  • Simian virus 40 / genetics
  • Simian virus 40 / immunology*
  • Surface Plasmon Resonance / methods*


  • Antigens, Viral, Tumor
  • DNA, Viral
  • DNA-Binding Proteins
  • Adenosine Triphosphatases
  • DNA Helicases