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Updated: Sep 3, 2026
Measuring In Vitro ATPase Activity for Enzymatic Characterization
Published on: August 23, 2016
Characterization of a p30 fraction from Rauscher leukemia virus which has an associated ATPase activity
Abstract:
The p30 antigen from Rauscher leukemia virus (R-MuLV) was separated into two fractions by chromatography on either phosphocellulose or DEAE-cellulose. The p30-I and p30-II were indistinguishable immunologically or by isoelectrofocusing and gel electrophoresis. An ATPase activity was tightly associated with p30-II that could not be separated by ion-exchange chromatography, isoelectrofocusing, or glycerol velocity gradient sedimentation. The ATPase hydrolyzed the gamma phosphate from only ATP or dATP. Immunoglobulin directed against R-MuLV p30 completely inhibited the p30-II associated ATPase. Glycerol velocity gradient analysis showed that p30-I sedimented as a 30-kDa species while the p30-II and its associated ATPase sedimented as a 60-kDa species. The p30-II was converted entirely to a 30-kDa form by treatment with 0.2% (w/v) lithium dodecyl sulfate, suggesting that it represented a complexed species of p30. Finally, p30-II was found to stimulate the activity of R-MuLV reverse transcriptase, but p30-I had no effect on the activity of the enzyme. These results suggested the existence of at least two different forms of p30 in R-MuLV.
Insights
Rauscher leukemia virus p30 antigen exists in two forms: p30-I and p30-II. p30-II, a complexed form, possesses ATPase activity and stimulates reverse transcriptase, unlike p30-I.
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- The p30 antigen is a key component of Rauscher leukemia virus (R-MuLV).
- Understanding the different forms and functions of viral antigens is crucial for studying viral replication and pathogenesis.
Purpose of the Study:
- To investigate the heterogeneity of the Rauscher leukemia virus p30 antigen.
- To characterize the biochemical properties and potential functions of different p30 forms.
Main Methods:
- Chromatographic separation (phosphocellulose, DEAE-cellulose) to isolate p30 fractions.
- Biochemical assays including ATPase activity measurement and reverse transcriptase stimulation assays.
- Physicochemical characterization using isoelectrofocusing, gel electrophoresis, and glycerol velocity gradient sedimentation.
Main Results:
- R-MuLV p30 antigen separated into two distinct fractions, p30-I and p30-II.
- p30-II exhibited tightly associated ATPase activity, hydrolyzing ATP/dATP, and was inhibited by anti-p30 immunoglobulin.
- p30-II existed as a 60-kDa complex, dissociating to 30-kDa upon SDS treatment, and stimulated R-MuLV reverse transcriptase activity, while p30-I did not.
Conclusions:
- Rauscher leukemia virus p30 antigen exists in at least two forms: a monomeric form (p30-I) and a complexed form (p30-II).
- The p30-II complex possesses enzymatic activity (ATPase) and modulates viral enzyme function (reverse transcriptase stimulation).
- These findings suggest distinct roles for different p30 forms in the Rauscher leukemia virus life cycle.
