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Atomic structure of the clamp loader small subunit from Pyrococcus furiosus.
1Department of Structural Biology and, Biomolecular Engineering Research Institute, 6-2-3 Furuedai, Suita-City, 565-0874, Osaka, Japan.
Molecular Cell
|September 8, 2001
Summary
Replication factor-C (RFC) is crucial for DNA replication. Researchers determined the crystal structure of the archaeal RFC small subunit (RFCS), revealing conserved features with eukaryotic clamp loaders.
Area of Science:
- Biochemistry
- Molecular Biology
- Structural Biology
Background:
- Replication factor-C (RFC) functions as a vital clamp loader in eukaryotic DNA replication, facilitating the installation of sliding clamps at replication forks.
- Eukaryotic RFC is a multi-subunit complex comprising one large and four small subunits.
Purpose of the Study:
- To determine the crystal structure of the clamp loader small subunit (RFCS) from the archaeon Pyrococcus furiosus.
- To elucidate the structural basis of RFCS assembly and its potential conservation with eukaryotic RFC.
Main Methods:
- X-ray crystallography was employed to determine the three-dimensional structure of Pyrococcus furiosus RFCS.
- Structural analysis focused on the subunit assembly, domain organization, and nucleotide-binding sites.
Main Results:
- The crystal structure of RFCS from Pyrococcus furiosus was determined, revealing a crescent-like architecture formed by three domains.
- RFCS subunits assemble into a dimer of semicircular trimers, with four subunits binding ADP.
- The observed architecture shows resemblance to the delta' subunit of the E. coli clamp loader, suggesting conserved structural motifs.
Conclusions:
- The trimeric architecture of archaeal RFCS, including mobile N-terminal domains and intersubunit interactions, may be conserved in functional eukaryotic RFC complexes.
- This structural insight provides a foundation for understanding the mechanism of clamp loading in both archaeal and eukaryotic systems.