Structural and functional analysis of the ARF1-ARFGAP complex reveals a role for coatomer in GTP hydrolysis
Structural and functional analysis of the ARF1-ARFGAP complex reveals a role for coatomer in GTP hydrolysis
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DOI：
10.1016/s0092-8674(00)80598-x
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发表时间：
1999-03-19
期刊：
影响因子：
64.5
通讯作者：
Goldberg, J
中科院分区：
文献类型：
--
作者：
Goldberg, J
在1.95埃的分辨率下测定了ARF1 GTPase与GDP结合的复合物的晶体结构和ARF gtase激活蛋白（ARFGAP）的催化结构域。ARFGAP分子结合开关2和螺旋α 3来定向ARF1残基进行催化，但它既不提供精氨酸也不提供其他氨基酸侧链到GTPase活性位点。在复合物中，效应结合区似乎是畅通的，这表明ARFGAP可以刺激GTP水解，而ARF1则与其效应物（copi包被囊泡的涂层复合物）保持相互作用。生化实验表明，coatomer直接参与GTP酶反应，以arfgap依赖的方式将GTP水解速度进一步加快1000倍。因此，三方复合物控制GTP水解反应，触发COPI囊泡外壳的分解。
The crystal structure of the complex of ARF1 GTPase bound to GDP and the catalytic domain of ARF GTPase-activating protein (ARFGAP) has been determined at 1.95 Angstrom resolution. The ARFGAP molecule binds to switch 2 and helix alpha 3 to orient ARF1 residues for catalysis, but it supplies neither arginine nor other amino acid side chains to the GTPase active site. In the complex, the effector-binding region appears to be unobstructed, suggesting that ARFGAP could stimulate GTP hydrolysis while ARF1 maintains an interaction with its effector, the coatomer complex of COPI-coated vesicles. Biochemical experiments show that coatomer directly participates in the GTPase reaction, accelerating GTP hydrolysis a further 1000-fold in an ARFGAP-dependent manner. Thus, a tripartite complex controls the GTP hydrolysis reaction triggering disassembly of COPI vesicle coats.