Here, we used for the first time Hydrogen-Deuterium eXchange coupled to Mass Spectrometry (HDX-MS) to investigate conformational differences between the human standard 20S (std20S) and immuno 20S (i20s) proteasomes alone or in complex with PA28αβ or PA28γ activators. Their solvent accessibility was analyzed through a dedicated bioinformatic pipeline including stringent statistical analysis and 3D visualization. These data confirmed the existence of allosteric differences between the std20S and i20S at the surface of the α-ring triggered from inside the catalytic β-ring. Additionally, binding of the PA28 regulators to the 20S proteasomes modified solvent accessibility due to conformational changes of the β-rings. This work is not only a proof-of-concept that HDX-MS can be used to get structural insights on large multi-protein complexes in solution, it also demonstrates that the binding of the std20S or i20S subtype to any of its PA28 activator triggers allosteric changes that are specific to this 20S/PA28 pair.

中文翻译：

---

人类20S蛋白酶体的构象图揭示了PA28和免疫依赖性环间串扰

在这里，我们首次使用氢-氘交换质谱（HDX-MS）来研究单独或与PA28αβ或PA28γ激活剂复合的人类标准20S（std20S）和免疫20S（i20s）蛋白酶体之间的构象差异。通过专用的生物信息学渠道对溶剂的可及性进行了分析，包括严格的统计分析和3D可视化。这些数据证实了从催化β环内部触发的α环表面上std20S和i20S之间存在变构差异。另外，由于β环的构象变化，PA28调节剂与20S蛋白酶体的结合改变了溶剂的可及性。这项工作不仅在概念上证明了HDX-MS可用于获得溶液中大型多蛋白复合物的结构见解，