X-ray scattering study of activated Arp2/3 complex with bound actin-WCA
X-ray scattering study of activated Arp2/3 complex with bound actin-WCA
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DOI：
10.1016/j.str.2008.02.013
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发表时间：
2008-05-01
期刊：
影响因子：
5.7
通讯作者：
Dominguez, Roberto
中科院分区：
文献类型：
--
作者：
Boczkowska, Malgorzata;Rebowski, Grzegorz;Dominguez, Roberto
Arp 2/3复合物的先前结构，在不存在成核促进因子和肌动蛋白的情况下确定，揭示了其非活性构象。活性结构的研究一直受到无法控制的聚合的阻碍。我们已经设计了一个稳定的激活复合物Arp 2/3复合物，WCA激活区的N-WASP，和一个肌动蛋白单体组成，并研究了其在溶液中的结构，通过小角X射线散射（SAXS）。散射数据支持一个模型，其中第一个肌动蛋白亚基结合在Arp 2的倒刺末端，并取消了替代模型，将第一个肌动蛋白亚基在Arp 3的倒刺末端。第一个肌动蛋白和结合的W基序的这个位置限制了C基序与亚基Arp 2和ARPC 1的结合位点，A基序可以从那里到达亚基Arp 3和ARPC 3。这些结果支持了一个与大多数生化观察结果一致的激活模型。
Previous structures of Arp2/3 complex, determined in the absence of a nucleation-promoting factor and actin, reveal its inactive conformation. The study of the activated structure has been hampered by uncontrollable polymerization. We have engineered a stable activated complex consisting of Arp2/3 complex, the WCA activator region of N-WASP, and one actin monomer, and studied its structure in solution by small angle X-ray scattering (SAXS). The scattering data support a model in which the first actin subunit binds at the barbed end of Arp2, and disqualify an alternative model that places the first actin subunit at the barbed end of Arp3. This location of the first actin and bound W motif constrains the binding site of the C motif to subunits Arp2 and ARPC1, from where the A motif can reach subunits Arp3 and ARPC3. The results support a model of activation that is consistent with most of the biochemical observations.