Molecular Biology & Microbial Food Safety, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Mass Spectrometry of Biomolecules, Swammerdam Institute for Life Sciences, University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands.
Int J Mol Sci. 2021 Nov 19;22(22):12475. doi: 10.3390/ijms222212475.
Membrane proteins are fascinating since they play an important role in diverse cellular functions and constitute many drug targets. Membrane proteins are challenging to analyze. The spore, the most resistant form of known life, harbors a compressed inner membrane. This membrane acts not only as a barrier for undesired molecules but also as a scaffold for proteins involved in signal transduction and the transport of metabolites during spore germination and subsequent vegetative growth. In this study, we adapted a membrane enrichment method to study the membrane proteome of spores and cells of the food-borne pathogen using quantitative proteomics. Using bioinformatics filtering we identify and quantify 498 vegetative cell membrane proteins and 244 spore inner membrane proteins. Comparison of vegetative and spore membrane proteins showed there were 54 spore membrane-specific and 308 cell membrane-specific proteins. Functional characterization of these proteins showed that the cell membrane proteome has a far larger number of transporters, receptors and proteins related to cell division and motility. This was also reflected in the much higher expression level of many of these proteins in the cellular membrane for those proteins that were in common with the spore inner membrane. The spore inner membrane had specific expression of several germinant receptors and spore-specific proteins, but also seemed to show a preference towards the use of simple carbohydrates like glucose and fructose owing to only expressing transporters for these. These results show the differences in membrane proteome composition and show us the specific proteins necessary in the inner membrane of a dormant spore of this toxigenic spore-forming bacterium to survive adverse conditions.
膜蛋白非常有趣，因为它们在多种细胞功能中发挥重要作用，并且构成了许多药物靶点。膜蛋白难以分析。孢子是已知生命中最具抵抗力的形式，它内部的膜结构被压缩。这种膜不仅作为阻挡不需要的分子的屏障，而且作为参与信号转导和代谢物运输的蛋白质的支架，在孢子萌发和随后的营养生长过程中发挥作用。在这项研究中，我们使用定量蛋白质组学方法，通过适应膜富集方法来研究食源性病原体的孢子和细胞的膜蛋白组。使用生物信息学过滤，我们鉴定和定量了 498 种营养细胞的膜蛋白和 244 种孢子内膜蛋白。营养细胞和孢子膜蛋白的比较表明，有 54 种孢子膜特异性蛋白和 308 种细胞膜特异性蛋白。对这些蛋白质的功能特征进行分析表明，细胞膜蛋白质组具有更多的转运蛋白、受体和与细胞分裂和运动相关的蛋白质。对于那些与孢子内膜共有的蛋白质，它们在细胞膜中的表达水平也更高，这一点也反映了这一点。孢子内膜特异性表达了几种发芽受体和孢子特异性蛋白，但由于只表达这些简单碳水化合物（如葡萄糖和果糖）的转运蛋白，它似乎也表现出对简单碳水化合物的偏好。这些结果显示了膜蛋白质组组成的差异，并使我们了解了这种产毒孢子形成细菌休眠孢子内膜中所需的特定蛋白质，以在不利条件下生存。
