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Characterization of an alkaline protease associated with a granulosis virus of Plodia interpunctella
Abstract:
An alkaline protease was found to be associated with the granulosis virus of the Indian meal moth. Plodia interpunctella. The protease was located within the protein matrix of the occluded virus and hydrolyzed the major constituent of this matrix, a 28,000-dalton protein (granulin), to a mixture of polypeptides ranging in molecular weight from 10,000 to 27,000. A rapid, sensitive assay for the protease was developed using radioactively labeled granulosis virus as substrate. With this assay, the proteolytic activity could be detected by measuring the release of acid-soluble peptides from the labeled virus. The protease had a pH optimum of 10.5 and a temperature optimum of 40 degrees C and was inhibited by diisopropyl phosphorofluoridate, phenylmethylsulfonyl fluoride, and L-(1-tosylamido-2-phenyl) ethyl chloromethyl ketone. Purification of the protease from matrix protein was achieved by anion-exchange and gel permeation chromatography. The molecular weight of the isolated protease, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, was approximately 14,000.
Insights
An alkaline protease associated with the Indian meal moth
Area of Science:
- Insect pathology
- Molecular biology
- Biochemistry
Background:
- The Indian meal moth, Plodia interpunctella, is a significant pest in stored products.
- Granulosis viruses are important pathogens used in biological control.
- Understanding viral components is crucial for developing effective pest management strategies.
Purpose of the Study:
- To identify and characterize the alkaline protease found within the P. interpunctella granulosis virus.
- To develop a sensitive assay for detecting protease activity.
- To purify and determine the properties of the viral protease.
Main Methods:
- Development of a sensitive assay using radioactively labeled granulosis virus.
- Enzyme kinetics studies to determine pH and temperature optima.
- Inhibition assays using specific protease inhibitors.
- Purification using anion-exchange and gel permeation chromatography.
- Molecular weight determination via SDS-PAGE and gel filtration.
Main Results:
- An alkaline protease was identified within the viral protein matrix.
- The protease hydrolyzes granulin (28,000-dalton protein) into smaller polypeptides.
- Optimal activity at pH 10.5 and 40°C.
- Protease activity was inhibited by specific chemical inhibitors.
- Purified protease has an approximate molecular weight of 14,000 daltons.
Conclusions:
- The P. interpunctella granulosis virus possesses an associated alkaline protease.
- This protease plays a role in degrading the viral protein matrix (granulin).
- The characterized protease can be utilized in sensitive detection assays for viral activity.