J. Biol. Chem., Vol. 261, Issue 24, 11173-11179, Aug, 1986
The interaction of nucleotides with pertussis toxin. Direct evidence for a nucleotide binding site on the toxin regulating the rate of ADP- ribosylation of Ni, the inhibitory regulatory component of adenylyl cyclase
R Mattera, J Codina, RD Sekura and L Birnbaumer
The interaction of nucleotides with pertussis toxin (PT), and their effects
on the ability of the toxin to ADP-ribosylate pure Ni, were evaluated.
[32P]ATP (10 nM) bound directly to dithiothreitol-activated PT. This
binding was competitively inhibited by nucleotides and anions with the
following IC50 concentrations in order of decreasing potency: ATP = ATP
gamma S (adenosine-5'-O-(3-thiotriphosphate)) = 0.2-0.3 microM, GDP beta S
(guanosine-5'-O-(2-thiodiphosphate)) = 2-3 microM, GTP gamma S
(guanosine-5'-O-(3-thiotriphosphate)) = 10-15 microM, ADP = 20-25 microM,
GTP = 30-40 microM, GMP-P(NH)P (guanyl-5'-yl imidodiphosphate) = 100-150
microM, GDP = 150-200 microM, Pi = SO4(2-) = 20 mM and Cl- = acetate =
30-35 mM. Treatment of PT with ATP, AMP- P(NH)P, GTP, GDP, or GDP beta S,
resulted in a stimulated state of NAD+- Ni ADP-ribosyltransferase activity.
Addition of ATP, AMP-P(NH)P (adenyl- 5'-yl imidodiphosphate), GTP, GDP, and
GDP beta S to the ADP- ribosylation reactions resulted in increased rates
of ADP-ribosyl-Ni formation. It is concluded that these effects on the
nucleotides are due to their action to stimulate the activity of PT. At
concentrations of PT between 0.04 and 0.4 microgram/ml, the stimulation of
ADP- ribosylation of Ni effected by nucleotides was hysteretic in nature,
exhibiting an approximately 25-min long lag when GDP was used as the
activating nucleotide. These lags decreased with increasing concentrations
of PT, and were abolished by pretreatment of the toxin with GDP or ATP.
Preliminary incubation of Ni with GDP had no effect on the lag in its
ADP-ribosylation by non-nucleotide treated PT. Addition of divalent cations
(Mg2+, Mn2+, and Ca2+) inhibited formation of ADP- ribosyl-Ni, possibly by
causing aggregation and denaturation of Ni. This is the first demonstration
that both adenine and guanine nucleotides interact directly with PT and act
to stimulate its activity to ADP-ribosylate Ni, and that guanine
nucleotides do so regardless of whether they are nucleoside di- or
triphosphates.