Pertussis Toxin-ATP Complex: Difference between revisions

'''Pertussis Toxin''' by itself is harmless unless activated.  From studies, it has became clear that there is a direct interaction between 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 then 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'>TextToBeDisplayed</scene><scene name='Pertussis_Toxin-ATP_Complex/5_amino_acid_interaction/1'>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_s1/1'>Phe 235:A and Tyr 233: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.