Department of Biology, Institute of Molecular Systems Biology, Eidgenössische Technische Hochschule Zürich, Wolfgang-Pauli Strasse 16, 8093 Zurich, Switzerland.
Science. 2012 Sep 14;337(6100):1348-52. doi: 10.1126/science.1221483.
The identification of proximate amino acids by chemical cross-linking and mass spectrometry (XL-MS) facilitates the structural analysis of homogeneous protein complexes. We gained distance restraints on a modular interaction network of protein complexes affinity-purified from human cells by applying an adapted XL-MS protocol. Systematic analysis of human protein phosphatase 2A (PP2A) complexes identified 176 interprotein and 570 intraprotein cross-links that link specific trimeric PP2A complexes to a multitude of adaptor proteins that control their cellular functions. Spatial restraints guided molecular modeling of the binding interface between immunoglobulin binding protein 1 (IGBP1) and PP2A and revealed the topology of TCP1 ring complex (TRiC) chaperonin interacting with the PP2A regulatory subunit 2ABG. This study establishes XL-MS as an integral part of hybrid structural biology approaches for the analysis of endogenous protein complexes.
通过化学交联和质谱（XL-MS）鉴定近氨基酸有助于均相蛋白质复合物的结构分析。我们通过应用改良的 XL-MS 方案，对从人细胞中亲和纯化的蛋白质复合物的模块化相互作用网络获得了距离约束。系统分析人蛋白磷酸酶 2A（PP2A）复合物，鉴定出 176 个蛋白间和 570 个蛋白内交联，将特定的三聚体 PP2A 复合物连接到多种衔接蛋白上，这些蛋白控制其细胞功能。空间约束指导免疫球蛋白结合蛋白 1（IGBP1）和 PP2A 之间的结合界面的分子建模，并揭示了 TCP1 环复合物（TRiC）分子伴侣与 PP2A 调节亚基 2ABG 的拓扑结构。这项研究确立了 XL-MS 作为分析内源性蛋白质复合物的混合结构生物学方法的一个组成部分。
