Ion mobility mass spectrometry (IM/MS) can provide structural information on intact protein complexes. Such data, including connectivity and collision cross sections (CCS) of assemblies' subunits, can in turn be used as a guide to produce representative super coarse-grained models. These models are constituted by ensembles of overlapping spheres, each representing a protein subunit. A model is considered plausible if the CCS and sphere-overlap levels of its subunits fall within predetermined confidence intervals. While the first is determined by experimental error, the latter is based on a statistical analysis on a range of protein dimers. Here, we first propose a new expression to describe the overlap between two spheres. Then we analyze the effect of specific overlap cutoff choices on the precision and accuracy of super coarse-grained models. Finally, we propose a method to determine overlap cutoff levels on a per-case scenario, based on collected CCS data, and show that it can be applied to the characterization of the assembly topology of symmetrical homo-multimers. Graphical Abstract.

中文翻译：

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关于球体重叠对蛋白质装配体的超粗颗粒模型的影响。

离子淌度质谱（IM / MS）可以提供完整蛋白质复合物的结构信息。这样的数据，包括装配体的子单元的连通性和碰撞横截面（CCS），又可以用作生成代表性的超粗粒度模型的指南。这些模型是由重叠的球体组成的，每个球体代表一个蛋白质亚基。如果CCS及其子单元的球面重叠水平落在预定的置信区间内，则该模型被认为是合理的。前者是由实验误差决定的，后者是基于对一系列蛋白质二聚体的统计分析。在这里，我们首先提出一个新的表达式来描述两个球体之间的重叠。然后，我们分析了特定的重叠截止选择对超粗粒度模型的精度和准确性的影响。最后，我们提出了一种基于收集的CCS数据确定每种情况下重叠截止水平的方法，并表明该方法可用于表征对称均聚物的组装拓扑。图形概要。