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Published on: December 17, 2016
Characterization of a new AAA+ protein from archaea
Heike Summer1, Roland Bruderer, Eilika Weber-Ban
1Institute of Molecular Biology and Biophysics, ETH Zürich, 8093 Zürich, Switzerland.
Journal of Structural Biology
|April 6, 2006
Summary
Researchers identified a novel hyperthermophilic archaeal ATPase, a member of the AAA+ protein family. This enzyme is stable up to 86°C and exhibits maximal activity at this temperature, suggesting unique roles in extremophiles.
Area of Science:
- Biochemistry
- Molecular Biology
- Archaea Research
Background:
- AAA+ proteins (ATPases associated with various cellular activities) are crucial molecular machines.
- A novel archaeal AAA+ protein was identified in methanogens and Archaeoglobus fulgidus, clustering to COG1223.
- This protein is homologous to bacterial FtsH and archaeal CDC48 family members.
Purpose of the Study:
- To characterize a newly identified archaeal AAA+ protein from Archaeoglobus fulgidus.
- To investigate its structure, assembly, and enzymatic activity.
Main Methods:
- Overexpression and purification of the A. fulgidus protein in E. coli.
- Electron microscopy for structural analysis.
- Sedimentation equilibrium analysis for complex assembly.
- ATP binding and hydrolysis assays, including Michaelis-Menten kinetics.
- Thermal stability and activity assays.
Main Results:
- The purified protein forms stable ring-shaped hexameric complexes.
- The enzyme binds and hydrolyzes ATP with a k(cat) of 118 min⁻¹ and K(M) of 1.4 mM at 78°C.
- The hyperthermophilic ATPase is stable to 86°C, with optimal activity at this temperature.
Conclusions:
- The characterized AAA+ protein is a hyperthermophilic enzyme with stable hexameric structure.
- Its properties suggest a role in cellular processes within extreme environments.
- Further investigation into its specific functions in archaea is warranted.
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