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Adenine nucleotides directly stimulate pertussis toxin
The Journal of Biological Chemistry
|March 10, 1985
Summary
Cholera toxin and pertussis toxin both ADP-ribosylate tubulin. Pertussis toxin requires adenine nucleotides, like ATP, for this activity, suggesting a direct nucleotide interaction influencing its enzymatic function.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Tubulin is a key protein in microtubule formation.
- Bacterial toxins like cholera toxin and pertussis toxin can modify cellular proteins through ADP-ribosylation.
- Understanding the enzymatic mechanisms of these toxins is crucial for cell biology research.
Purpose of the Study:
- To investigate the ADP-ribosylating activity of cholera toxin and pertussis toxin on bovine brain tubulin.
- To determine the role of nucleotides in the enzymatic activity of pertussis toxin.
Main Methods:
- Purification of bovine brain tubulin.
- Incubation of tubulin with cholera toxin and pertussis toxin.
- Assaying ADP-ribosylation in the presence and absence of various nucleotides and EDTA.
- Testing the effect of adenine nucleotides on heat-treated bovine serum albumin and NAD hydrolysis by pertussis toxin.
Main Results:
- Both cholera toxin and pertussis toxin catalyzed ADP-ribosylation of tubulin.
- Cholera toxin's activity was independent of nucleotides.
- Pertussis toxin required adenine nucleotides (e.g., ATP, ADP) for its ADP-ribosylating activity.
- Nucleotide hydrolysis was not necessary for pertussis toxin activity.
- Adenine nucleotides directly enhanced pertussis toxin activity, as evidenced by increased NAD hydrolysis.
Conclusions:
- Pertussis toxin's ADP-ribosylating activity on tubulin is directly modulated by adenine nucleotides.
- Adenine nucleotides appear to directly interact with and activate pertussis toxin.
- These findings provide insights into the regulatory mechanisms of bacterial toxin enzymatic function.