Pertussis Toxin-ATP Complex: Difference between revisions

'''Pertussis Toxin''' by itself is harmless unless activated.  From multiple studies, it has became clear that there is a direct interaction between [http://en.wikipedia.org/wiki/Adenosine_triphosphate Adenosine triphosphate] (ATP) and pertussis toxin which leads to activation.  The direct effect of ATP is to destabilize the interaction between the S1 subunit and the B-oligomer by binding to the B-oligomer.  This interaction relaxes the toxin by facilitating the subsequent reduction of  a disulphide bond in the S1 subunit.  The main interaction that leads to the destabilization is the favorable hydrogen bonding and electrostatic interaction between the triphosphate moiety and five positively charged amino acids:<scene name='Pertussis_Toxin-ATP_Complex/5_amino_acid_interaction/2'>Arg S2:150, Lys S2-151, Arg S3-150, and Arg S4b-69</scene>. In contrast, the negatively charged carboxyl terminus of subunit S1 interacts unfavorably with the negative charges of the triphosphate moiety, causing a displacement of the C-terminal of <scene name='Pertussis_Toxin-ATP_Complex/Repulsion_of_subunit_s1/3'>Tyr 233:A and Phe 235:A</scene>  therefore,  the repulsion between the triphosphate moiety and the C terminus of subunit S1 forms the mechanism by which the interaction between S1 and the B-Oligomer is destabilized.