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Published on: August 29, 2015
Identification of a protein kinase activity in purified foot- and-mouth disease virus
Abstract:
Purified preparations of foot-and-mouth disease virus types A, O, and C contain a protein kinase activity which can transfer the gamma phosphate of [32P]ATP to virion structural proteins VP2 and VP3 and exogenous acceptor proteins. Utilizing protamine sulfate as an acceptor, the kinase activity can be demonstrated in disrupted virus but not in intact virus. The enzyme is heat labile with optimal activity at pH 7 or greater. Serine residues of protamine sulfate were identified as the amino acid phosphorylated by the protein kinase. Treatment of purified virus with trypsin, which cleaves VP3, did not affect the protein kinase activity. The results indicate that the protein kinase activity found in FMDV is present in an internally located protein of viral or host origin.
Insights
Foot-and-mouth disease virus (FMDV) contains an internal protein kinase. This enzyme phosphorylates viral proteins VP2 and VP3, and is heat labile with optimal activity at pH 7.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Foot-and-mouth disease virus (FMDV) is a significant pathogen affecting livestock.
- Understanding viral enzyme activities is crucial for developing antiviral strategies.
Purpose of the Study:
- To investigate the presence and characteristics of protein kinase activity within purified FMDV preparations.
- To identify the viral components targeted by this kinase.
Main Methods:
- Purified FMDV types A, O, and C were used.
- Phosphorylation assays were performed using [32P]ATP and various protein acceptors, including protamine sulfate.
- Enzyme activity was assessed under different conditions (pH, heat) and after viral disruption or treatment.
Main Results:
- FMDV preparations exhibited protein kinase activity, phosphorylating viral proteins VP2 and VP3, and exogenous substrates.
- The kinase activity was detected in disrupted, but not intact, FMDV.
- The enzyme was heat labile and optimally active at pH 7 or higher, with serine residues identified as the phosphorylation site on protamine sulfate.
- Trypsin treatment of VP3 did not abolish kinase activity.
Conclusions:
- FMDV possesses an intrinsic protein kinase activity.
- This activity is associated with an internally located protein, likely of viral or host origin.
- The kinase targets viral structural proteins, suggesting a potential role in the viral life cycle.
