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Updated: Aug 5, 2026
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Optimization of Synthetic Proteins: Identification of Interpositional Dependencies Indicating Structurally and/or Functionally Linked Residues
Published on: July 14, 2015
Structural and Functional Roles of Arg85-Mediated Inter-Motif Interactions in Human dUTPase
Moeka Nakashima1, Honoka Teruya1, Yuuna Horinouchi2
1Department of Food Science and Nutrition, Faculty of Human Life and Environment, Nara Women's University, Nara, Japan.
Proteins
|July 30, 2026
Summary
Human dUTPase maintains genome integrity by preventing uracil incorporation into DNA. A key residue, Arg85, is crucial for its catalytic activity and influences DNA repair mechanisms.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Human dUTPase (dUTP pyrophosphatase) is essential for genome integrity.
- It prevents uracil incorporation into DNA by hydrolyzing dUTP to dUMP.
- Catalytic activity involves five conserved motifs (I-V) forming the active site.
Purpose of the Study:
- To elucidate the structural and functional roles of Arg85 in human dUTPase.
- To define the contribution of Arg85 to the enzyme's catalytic mechanism.
Main Methods:
- X-ray crystallography of wild-type and Arg85 mutant dUTPase.
- Enzymatic assays to assess catalytic activity.
- Structural comparisons to identify functional interactions.
Main Results:
- Mutations at Arg85 did not cause significant global structural changes.
- A positive charge at position 85 is essential for efficient dUTPase catalysis.
- Arg85 modulates the orientation of Arg128 via an inter-motif interaction network.
- Disrupting this network by mutating Arg85 or Arg128 reduces enzyme activity.
Conclusions:
- Arg85 plays a critical role in human dUTPase catalysis by influencing the active site network.
- These findings provide a mechanistic basis for understanding disease-associated variants affecting Arg85 and Arg128.
- The study highlights the importance of specific residue interactions for maintaining genome stability.
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