Staphylococcus aureus phenol soluble modulin aggregation kinetics

The infective ability of the opportunistic pathogen Staphylococcus aureus, recognized as the most frequent cause of biofilm-associated infections, is associated with biofilm mediated resistance to host immune response. Phenol-soluble modulins (PSM) comprise the structural scaffold of S. aureus biofilms through self-assembly into functional amyloids, but the role of individual PSMs during biofilm formation remains poorly understood and the molecular pathways of PSM self-assembly have yet to be identified. Here, we demonstrate high degree of cooperation between individual PSMs during functional amyloid formation. PSMα3 initiates the aggregation, forming unstable aggregates capable of seeding other PSMs resulting in stable amyloid structures. Using chemical kinetics we dissect the molecular mechanism of aggregation of individual PSMs showing that PSMα1, PSMα3 and PSMβ1 display secondary nucleation whereas PSMβ2 aggregates through primary nucleation and elongation. Our findings suggest that the various PSMs have evolved to ensure fast and efficient biofilm formation through cooperation between individual peptides.

Methods
The dataset was collected using Thioflavin T fluoresence for the detection of protien aggregates using a plate-reader assay.

The dataset was processed using chemical kinetics from the amylofit webserver (www.amylofit.ch.cam.ac.uk).

作为生物膜相关感染最常见的致病菌，机会致病菌金黄色葡萄球菌（Staphylococcus aureus）的感染能力与其生物膜介导的宿主免疫抵抗密切相关。酚可溶性调节蛋白（Phenol-soluble modulins, PSM）可通过自组装形成功能性淀粉样蛋白，构成金黄色葡萄球菌生物膜的结构支架，但目前学界对单个PSM在生物膜形成过程中的作用仍知之甚少，PSM自组装的分子通路也尚未明确。本研究证实了各PSM单体在功能性淀粉样蛋白形成过程中存在高度协同作用：PSMα3启动聚集过程，形成不稳定聚集体并可作为种子诱导其他PSM聚集，最终形成稳定的淀粉样结构。本研究利用化学动力学分析，解析了各PSM单体聚集的分子机制，结果显示PSMα1、PSMα3与PSMβ1均存在次级成核现象，而PSMβ2则通过初级成核与延伸完成聚集。本研究结果表明，各类PSM通过单体间的协同作用，进化出了快速高效的生物膜形成机制。

方法
本数据集通过酶标仪检测法，利用硫黄素T（Thioflavin T）荧光信号检测蛋白质聚集体完成采集。
本数据集通过amylofit在线服务器（www.amylofit.ch.cam.ac.uk）的化学动力学分析工具完成处理。