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Substrate specificity of the neuraminidase of different mumps virus strains
Abstract:
The hydrolysis of neuraminlactose, fetuin, ovomucoid, kappa-caseinglycopeptide and mucine from the bovine submaxillary gland with the neuraminidase (NA) of mumps virus strains Jeryl Lynn, Enders and Berlin 9/76 was investigated to determine the pH-dependence of the reaction with the different substrates. The corresponding curves showed splitting into several peaks with reaction maxima ranging from pH 4.7 to pH 6.7. This occurred probably due to the heterogeneity of the virus samples. The NA of each virus strain had the best reaction affinity to neuraminlactose followed by decreasing affinities to ovomucoid, fetuin and kappa-caseinglycopeptide. The mucine from bovine submaxillary gland was not digested at all. The highest hydrolysis of each substrate was found with the Jeryl Lynn strain, which also possessed the lowest substrate specificity. It was followed by that of strain Enders and finally by isolate Berlin 9/76 which, in turn, had the highest substrate specificity. The lower substrate specificity of mumps virus NA seemed to correlate with a lower degree of its cytopathogenicity for hamster ependyma cells.
Insights
Mumps virus neuraminidase (NA) exhibits varying pH-dependent hydrolysis across substrates, with Jeryl Lynn strain showing broad activity and Berlin 9/76 demonstrating high specificity. Lower specificity correlated with reduced cytopathogenicity.
Area of Science:
- Virology
- Enzymology
- Biochemistry
Background:
- Neuraminidase (NA) is a key enzyme in viral replication and host cell interactions.
- Mumps virus NA activity is crucial for understanding viral pathogenesis and developing antiviral strategies.
- Substrate specificity and pH dependence of NA can vary significantly between viral strains.
Purpose of the Study:
- To investigate the pH-dependence of mumps virus neuraminidase (NA) activity.
- To compare the substrate specificity of NA from different mumps virus strains (Jeryl Lynn, Enders, Berlin 9/76).
- To explore the relationship between NA substrate specificity and its cytopathogenicity.
Main Methods:
- Hydrolysis assays were performed on various substrates including neuraminlactose, fetuin, ovomucoid, kappa-caseinglycopeptide, and bovine submaxillary gland mucin.
- The activity of NA from mumps virus strains Jeryl Lynn, Enders, and Berlin 9/76 was assessed across a range of pH values.
- Substrate specificity and reaction optima were determined for each viral strain.
Main Results:
- Mumps virus NA activity exhibited pH optima ranging from 4.7 to 6.7, with multiple peaks suggesting enzyme heterogeneity.
- Neuraminlactose was the preferred substrate for all tested NA strains, followed by ovomucoid, fetuin, and kappa-caseinglycopeptide.
- Bovine submaxillary gland mucin was resistant to digestion by all mumps virus NA strains.
- The Jeryl Lynn strain displayed the highest hydrolysis activity and lowest substrate specificity, while the Berlin 9/76 isolate showed the highest substrate specificity.
- A correlation was observed between lower substrate specificity of mumps virus NA and reduced cytopathogenicity in hamster ependyma cells.
Conclusions:
- Mumps virus neuraminidase activity is pH-dependent and exhibits strain-specific variations in substrate preference.
- The Jeryl Lynn strain possesses broader NA activity compared to the Enders and Berlin 9/76 strains.
- Reduced substrate specificity of mumps virus NA may be linked to decreased cytopathogenicity, offering insights into viral virulence mechanisms.