Characterization of the integral membrane proteome by mass spectrometry (MS) remains challenging due its high complexity and inherent insolubility. In a typical experiment, the cellular membranes are isolated, the proteins are solubilized and fractionated, and the detergent micelles are removed before MS analysis. Detergents are not compatible with mass spectrometry, however, and their removal from biological samples often results in reduced protein identification. As an alternative to detergents, we recently developed the peptidisc membrane mimetic, which allows entrapment of the cell envelope proteome into water-soluble particles, termed a “peptidisc library”. Here, we employ a His-tagged version of the peptidisc peptide scaffold to enrich the reconstituted membrane proteome by affinity chromatography. This purification step reduces the sample complexity by depleting ribosomal and soluble proteins that often cosediment with cellular membranes. As a result, the peptidisc library is enriched in low-abundance membrane proteins. We apply this method to survey changes in the membrane proteome upon depletion of the SecDFyajC complex, the ancillary subunit of the Sec translocon. In the depleted strain, we detect increased membrane localization of the motor ATPase SecA, along with increased levels of an unannotated inner membrane protein, YibN. Together, these results demonstrate the utility of the peptidisc for global purification of membrane proteins and for monitoring change in the membrane proteome.

中文翻译：

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His标记的肽段能够对膜蛋白质组进行亲和纯化，以用于下游质谱分析。

由于其高复杂性和固有的不溶性，通过质谱（MS）表征整体膜蛋白质组学仍然具有挑战性。在一个典型的实验中，分离细胞膜，将蛋白质溶解并分级分离，并在MS分析之前去除去污剂胶束。然而，洗涤剂与质谱法不兼容，并且从生物样品中去除它们通常会导致蛋白质鉴定减少。作为去污剂的替代品，我们最近开发了拟肽膜模拟物，该模拟物可将细胞被膜蛋白质组截留到称为“拟肽库”的水溶性颗粒中。在这里，我们采用His标记版本的肽基肽支架，通过亲和层析富集重构的膜蛋白质组。该纯化步骤通过消耗核糖体蛋白和可溶性蛋白（这些蛋白经常与细胞膜形成沉淀）来降低样品的复杂性。结果，肽库富含低丰度膜蛋白。我们应用这种方法来调查SecDFyajC复合体，Sec translocon的辅助亚基的消耗后膜蛋白质组的变化。在枯竭的菌株中，我们检测到运动型ATPase SecA的膜定位增加，以及未注释的内膜蛋白YibN的水平增加。总之，这些结果证明了该肽在膜蛋白的整体纯化和膜蛋白组监测中的应用。肽库富含低丰度膜蛋白。我们应用这种方法来调查SecDFyajC复合体，Sec translocon的辅助亚基的消耗后膜蛋白质组的变化。在枯竭的菌株中，我们检测到运动型ATPase SecA的膜定位增加，以及未注释的内膜蛋白YibN的水平增加。总之，这些结果证明了该肽在膜蛋白的整体纯化和膜蛋白组监测中的应用。肽库富含低丰度膜蛋白。我们应用这种方法来调查SecDFyajC复合体，Sec translocon的辅助亚基的消耗后膜蛋白质组的变化。在枯竭的菌株中，我们检测到运动型ATPase SecA的膜定位增加，以及未注释的内膜蛋白YibN的水平增加。总之，这些结果证明了该肽在膜蛋白的整体纯化和膜蛋白组监测中的应用。以及未注释的内膜蛋白YibN的水平升高。总之，这些结果证明了该肽在膜蛋白的整体纯化和膜蛋白组监测中的应用。以及未注释的内膜蛋白YibN的水平升高。总之，这些结果证明了该肽在膜蛋白的整体纯化和膜蛋白组监测中的应用。