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Isolation of Viral Replication Compartment-enriched Sub-nuclear Fractions from Adenovirus-infected Normal Human Cells
Published on: November 12, 2015
Adenovirus type 2 endoprotease: isoforms and redox effects
H Keyvani-Amineh1, M Diouri, K Tihanyi
1Department of Microbiology, Faculty of Medicine, University of Sherbrooke, Quebec, Canada.
The Journal of General Virology
|September 1, 1996
Summary
Adenovirus type 2 cysteine protease activity is modulated by oxidation and specific cysteine residues. Researchers identified potential binding sites for the activating peptide pVIc, crucial for enzyme function.
Area of Science:
- Biochemistry
- Virology
- Enzymology
Background:
- Adenovirus type 2 cysteine protease is essential for viral replication.
- The enzyme's catalytic activity and activation mechanism involve specific cysteine residues.
Purpose of the Study:
- To investigate the impact of oxidation and reducing agents on adenovirus type 2 cysteine protease activity.
- To identify the specific cysteine residues involved in enzyme activation and peptide binding.
Main Methods:
- Enzyme activity assays using wild-type and mutant adenovirus type 2 cysteine protease.
- Treatment with oxidizing agents (diamide) and reducing agents (mercaptoethanol, dithiothreitol).
- Analysis of enzyme isoforms in infected cells and recombinant preparations.
Main Results:
- Three enzyme isoforms were detected in infected cells; a fourth was found in purified recombinant enzyme.
- Mutations at conserved cysteines (C-104, C-122, C-126) affected isoform presence.
- Cysteamine stimulated enzyme activity, though less efficiently than the authentic peptide (pVIc).
- Diamide showed complex effects, stimulating at low concentrations and inhibiting at higher concentrations.
- Protein disulfide isomerase did not restore activity to the oxidized enzyme.
Conclusions:
- Cysteine residues C-17, C-40, and C-104 are potential binding sites for the activating peptide pVIc.
- Specific cysteine residues are critical for enzyme activation and isoform formation.
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