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Structure-based identification of a novel NTPase from Methanococcus jannaschii
K Y Hwang1, J H Chung, S H Kim
1Structural Biology Center, Korea Institute of Science and Technology, Seoul, South Korea.
Nature Structural Biology
|July 15, 1999
Summary
Researchers identified the function of a hypothetical protein from Methanococcus jannaschii (Mj0226). This novel nucleotide triphosphatase efficiently hydrolyzes nonstandard nucleotides, aiding in understanding microbial protein functions.
Area of Science:
- Biochemistry
- Structural Biology
- Microbiology
Background:
- Methanococcus jannaschii has many hypothetical proteins with unknown functions.
- Mj0226 is a gene encoding a protein of unknown function in M. jannaschii.
Purpose of the Study:
- To determine the biochemical function of the Mj0226 protein from M. jannaschii.
- To characterize a novel protein using structural and biochemical methods.
Main Methods:
- X-ray crystallography to determine the 3D structure of Mj0226 at 2.2 Å resolution.
- Database comparisons to identify structural homologies.
- Biochemical assays to test nucleotide hydrolysis activity.
Main Results:
- Mj0226 is a homodimeric protein with a unique alpha/beta fold.
- Structural analysis revealed homology to nucleotide-binding proteins.
- Biochemical assays identified Mj0226 as a novel nucleotide triphosphatase.
- The enzyme efficiently hydrolyzes nonstandard nucleotides (XTP, ITP) but not standard nucleotides in the presence of Mg2+ or Mn2+.
Conclusions:
- The Mj0226 protein is a novel nucleotide triphosphatase with specific substrate preferences.
- Structure-based functional identification advances our understanding of hypothetical proteins in M. jannaschii.
- This discovery contributes to the functional annotation of microbial genomes.