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Particle Agglutination Method for Poliovirus Identification
Published on: April 20, 2011
Poliovirus 2C protein forms homo-oligomeric structures required for ATPase activity
Peter Adams1, Eaazhisai Kandiah2, Grégory Effantin2
1NIAID, Bethesda, Maryland 20892-8011.
The Journal of Biological Chemistry
|June 13, 2009
Summary
Poliovirus protein 2C forms ring-like oligomers essential for ATPase activity, crucial for viral RNA replication. Inactive subunits or N-terminal deletions disrupt these structures and abolish function.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- Poliovirus protein 2C is vital for viral RNA replication.
- Its biochemical activities and structural needs remain unclear.
- 2C shares conserved properties with SF3 helicase family AAA+ ATPases, known for ring formation.
Purpose of the Study:
- To investigate the oligomeric state and ATPase activity of poliovirus 2C protein.
- To determine the structural requirements for 2C's enzymatic function.
Main Methods:
- Recombinant maltose-binding protein-2C (MBP-2C) fusion protein expression and purification.
- Gel-filtration chromatography to separate oligomeric states.
- Negative-staining and scanning transmission electron microscopy for structural visualization.
- Site-directed mutagenesis of the nucleotide-binding domain and N-terminus.
Main Results:
- MBP-2C forms soluble oligomers with associated ATPase activity.
- Electron microscopy revealed ring-like particles (5-8 protomers) in active fractions.
- Mutations affecting ATP binding/hydrolysis did not prevent oligomerization.
- N-terminal deletion (1-38 aa) abolished oligomerization and ATPase activity.
- Inactive subunits incorporated into mixed oligomers reduced overall ATPase activity.
Conclusions:
- Poliovirus 2C protein oligomerizes into ring structures essential for its ATPase activity.
- Oligomerization, not nucleotide binding, is the primary determinant of 2C's catalytic function.
- The N-terminus is critical for the assembly of functional 2C oligomers.
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