Dimerization of the human cytomegalovirus protease: kinetic and biochemical characterization of the catalytic homodimer
| Autor: | Stephen A. Margosiak, Chen-Chen Kan, Darin L. Vanderpool, Wes Sisson, Christopher Pinko |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Glycerol
Hot Temperature Light Protein Conformation medicine.medical_treatment Cytomegalovirus Sodium Chloride medicine.disease_cause Biochemistry Catalysis Citric Acid Endopeptidases Enzyme Stability medicine Escherichia coli Scattering Radiation Citrates Mutation Protease Molecular mass Chemistry Serine Endopeptidases In vitro Peptide Fragments Dissociation constant Kinetics Cross-Linking Reagents Energy Transfer Models Chemical Protein quaternary structure Specific activity Assemblin Protein Binding |
| Zdroj: | Biochemistry. 35(16) |
| ISSN: | 0006-2960 |
| Popis: | The single-chain 28 kDa human cytomegalovirus (HCMV) protease catalytic domain containing the A143Q mutation has been kinetically and conformationally characterized. The specific activity of the HCMV A143Q protease (HCMVp) increases as the protease concentration increases, suggesting that this protease oligomerizes at high protein concentration to form a more active species. Both cross-linking and light-scattering studies of HCMVp show the existence of a homodimer with an apparent molecular mass of 56 kDa under low ionic strength and high protein concentration. The cosolvent and solute effects of glycerol, trisodium citrate, and NaCl as well as the temperature effects on the HCMVp activity and quaternary structure were investigated. The effects induced by cosolvents and temperature can largely be explained by their influences in the dimerization or oligomerization state of HCMVp. The dissociation constant (Kd) for the HCMVp homodimer was determined to be 8 +/- 1 microM with all activity attributed to the dimeric form. Monomeric HCMVp is inactive. This report demonstrates that in vitro, HCMV A143Q protease exists as an obligate catalytic homodimer. This protease dimerization may have regulatory significance during viral replication. |
| Databáze: | OpenAIRE |
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