Interaction of the two cytosolic domains of mammalian adenylyl cyclase
Interaction of the two cytosolic domains of mammalian adenylyl cyclase
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DOI：
10.1073/pnas.93.13.6621
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发表时间：
1996-06-25
影响因子：
11.1
通讯作者：
Dessauer, CW
中科院分区：
文献类型：
--
作者：
Whisnant, RE;Gilman, AG;Dessauer, CW
腺苷酸环化酶活性可以通过酶的两个胞质结构域在大肠杆菌中独立合成后的简单混合物来重建。我们合成并纯化了 I 型腺苷酸环化酶的 C-1a 结构域和 II 型酶的 C-2 结构域，以评估它们之间以及与激活剂 G(s α) 和毛喉素的相互作用。在没有激活剂的情况下，片段以低亲和力缔合并显示出低亲和力。催化活性，这种基础活性可以被毛喉素或活化的 G(s alpha) 刺激超过 100 倍。此外，这些激活剂的添加增加了片段彼此之间的表观亲和力。G(sα)和毛喉素对催化的刺激是协同的。这些数据表明了一个模型，其中 G(s α) 或毛喉素增强另一种激活剂与腺苷酸环化酶的关联，并促进酶的 C-1 和 C-2 结构域之间的相互作用。
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 C-2 domain of the type II enzyme to assess their interactions with each other and with the activators G(s alpha) 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(s alpha). Further, the addition of these activators increases the apparent affinity of the fragments for each other, Stimulation of catalysis by G(s alpha) and forskolin is synergistic. These data suggest a model wherein either G(s alpha) or forskolin enhances association of the other activator with adenylyl cyclase, as well as facilitating the interaction between the C-1 and C-2 domains of the enzyme.