The monomeric dUTPase from Epstein-Barr virus mimics trimeric dUTPases

Area of Science:

• Biochemistry
• Structural Biology
• Enzymology

Background:

• Deoxyuridine 5 -triphosphate pyrophosphatases (dUTPases) are crucial enzymes involved in DNA metabolism, catalyzing the hydrolysis of dUTP to dUMP and pyrophosphate.
• These enzymes exist in monomeric, dimeric, and trimeric forms, with distinct structural and sequence characteristics.
• Monomeric dUTPases are exclusively found in herpesviruses, including Epstein-Barr virus (EBV).

Purpose of the Study:

• To elucidate the three-dimensional structure of Epstein-Barr virus (EBV) dUTPase.
• To investigate the structural basis for the enzymatic activity of monomeric dUTPases.
• To compare the structure of EBV dUTPase with other known dUTPase forms.

Main Methods:

• X-ray crystallography was employed to determine the crystal structures.
• Structures were solved for EBV dUTPase in complex with the product deoxyuridine monophosphate (dUMP).
• Structures were also determined in complex with a substrate analog, alpha,beta-imino-dUTP.

Main Results:

• The crystal structure of EBV dUTPase reveals a three-domain organization.
• These three domains assemble to form a single active site.
• The active site architecture is highly similar to one active site of trimeric dUTPases, with domains I and II adopting the dUTPase fold.
• Domain III exhibits limited secondary structure and contributes to the unique active site formation.

Conclusions:

• The monomeric EBV dUTPase, despite its distinct domain arrangement, functionally mimics the active sites of trimeric dUTPases.
• The structural findings provide insights into the evolution and functional diversification of dUTPases across different viral families.
• This study enhances our understanding of the structural basis for dUTPase inhibition, potentially aiding in antiviral drug development.