Adenylyl cyclase activity can be reconstituted by simple mixture of the two cytosolic domains of the enzyme after their independent synthesis in Escherichia coli. We have synthesized and purified the C(1a) domain of type I adenylyl cyclase and the C2 domain of the type II enzyme to assess their interactions with each other and with the activators G(sα) and forskolin. In the absence of an activator, the fragments associate with low affinity and display low catalytic activity. This basal activity can be stimulated more than 100-fold by either forskolin or activated G(sα). Further, the addition of these activators increases the apparent affinity of the fragments for each other. Stimulation of catalysis by G(sα) and forskolin is synergistic. These data suggest a model wherein either G(sα) or forskolin enhances association of the other activator with adenylyl cyclase, as well as facilitating the interaction between the C1 and C2 domains of the enzyme.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Jun 25 1996|
- G proteins
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