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DNA and ATP binding activities of the baculovirus DNA helicase P143

V V McDougal1, L A Guarino

  • 1Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, USA.

Journal of Virology
|July 4, 2001
PubMed

Insights

The P143 DNA helicase binds DNA tightly, but ATP and Mg(2+) cause it to release DNA. This suggests an inchworm mechanism for DNA unwinding by P143.

Area of Science:

  • Molecular Biology
  • Biochemistry
  • Genetics

Background:

  • P143 is a protein involved in DNA replication and repair.
  • DNA helicases are essential enzymes that unwind DNA.
  • Understanding DNA helicase mechanisms is crucial for comprehending DNA metabolism.

Purpose of the Study:

  • To investigate the DNA binding properties of P143.
  • To elucidate the role of ATP hydrolysis in P143's DNA binding.
  • To determine the mechanism by which P143 unwinds DNA.

Main Methods:

  • DNA binding assays were performed to assess P143's affinity for double-stranded and single-stranded DNA.
  • The effect of ATP and Mg(2+) on DNA-protein complex stability was measured.
  • Data were analyzed to support or refute proposed DNA unwinding models.

Main Results:

  • P143 demonstrated strong binding to both double-stranded and single-stranded DNA.
  • DNA-protein complexes involving P143 rapidly dissociated in the presence of ATP and Mg(2+).
  • These results indicate that ATP hydrolysis induces a conformational change in P143, reducing its DNA affinity.

Conclusions:

  • ATP hydrolysis is critical for P143's DNA release.
  • The findings support an inchworm model for P143-mediated DNA unwinding.
  • P143 functions as a DNA helicase utilizing an ATP-dependent mechanism for DNA translocation.

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