Quintyn Royston S, Yan Jing, Wysocki Vicki H
Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA.
Department of Chemistry and Biochemistry, Ohio State University, Columbus, OH 43210, USA.
Chem Biol. 2015 May 21;22(5):583-92. doi: 10.1016/j.chembiol.2015.03.019. Epub 2015 Apr 30.
Understanding of protein complex assembly and the effect of ligand binding on their native topologies is integral to discerning how alterations in their architecture can affect function. Probing the disassembly pathway may offer insight into the mechanisms through which various subunits self-assemble into complexes. Here, a gas-phase dissociation method, surface-induced dissociation (SID) coupled with ion mobility (IM), was utilized to determine whether disassembly pathways are consistent with the assembly of three homotetramers and to probe the effects of ligand binding on conformational flexibility and tetramer stability. The results indicate that the smaller interface in the complex is initially cleaved upon dissociation, conserving the larger interface, and suggest that assembly of a D2 homotetramer from its constituent monomers occurs via a C2 dimer intermediate. In addition, we demonstrate that ligand-mediated changes in tetramer SID dissociation behavior are dependent on where and how the ligand binds.
了解蛋白质复合物的组装以及配体结合对其天然拓扑结构的影响，对于洞察其结构改变如何影响功能至关重要。探究解离途径可能有助于深入了解各种亚基自组装成复合物的机制。在此，采用了一种气相解离方法，即表面诱导解离（SID）与离子淌度（IM）相结合，来确定解离途径是否与三种同四聚体的组装一致，并探究配体结合对构象灵活性和四聚体稳定性的影响。结果表明，复合物中较小的界面在解离时首先被裂解，从而保留较大的界面，这表明D2同四聚体由其组成单体组装时通过C2二聚体中间体发生。此外，我们证明配体介导的四聚体SID解离行为的变化取决于配体的结合位置和方式。
