High-Resolution Mass Spectrometry Based Proteomic Analysis of the Response to Vancomycin-Induced Cell Wall Stress in Streptomyces coelicolor A3(2)

Understanding how bacteria survive
periods of cell wall stress
is of fundamental interest and can help generate ideas for improved
antibacterial treatments. In this study we use tandem mass tagging
to characterize the proteomic response of vancomycin resistant Streptomyces coelicolor to
the exposure to sublethal levels of the antibiotic. A common set of
804 proteins were identified in triplicate experiments. Contrasting
changes in the abundance of proteins closely associated with the cytoplasmic
membrane with those taking place in the cytosol identified aspects
of protein spatial localization that are associated with the response
to vancomycin. Enzymes for peptidoglycan precursor, mycothiol, ectoine
and menaquinone biosynthesis together with a multisubunit nitrate
reductase were recruited to the membrane following vancomycin treatment.
Many proteins with regulatory functions (including sensor protein
kinases) also exhibited significant changes in abundance exclusively
in the membrane-associated protein fraction. Several enzymes predicted
to be involved in extracellular peptidoglycan crossbridge formation
became significantly depleted from the membrane. A comparison with
data previously acquired on the changes in gene transcription following
vancomycin treatment identified a common high-confidence set of changes
in gene expression. Generalized changes in protein abundance indicate
roles for proteolysis, the pentose phosphate pathway and a reorganization
of amino acid biosynthesis in the stress response.

探究细菌如何在细胞壁应激期间存活，这一课题具有根本性的学术价值，并有助于激发针对抗菌治疗的创新理念。在本研究中，我们运用串联质谱标记技术，对具有万古霉素耐药性的链霉菌明串珠色变种在暴露于抗生素亚致死浓度下的蛋白质组学反应进行表征。在重复的三次实验中，共鉴定出804种常见的蛋白质。通过对与细胞质膜密切相关蛋白丰度的变化与细胞质中发生的变化的对比分析，揭示了与万古霉素响应相关的蛋白空间定位特征。在万古霉素处理后，参与肽聚糖前体、麦考酚、 ectoine 和叶黄素生物合成的酶以及多亚基硝酸盐还原酶被招募至细胞膜。许多具有调节功能的蛋白（包括感应蛋白激酶）在膜结合蛋白组分中也表现出丰度的显著变化。预测参与细胞外肽聚糖交联桥形成的数种酶在膜中显著减少。与先前获得的万古霉素处理后基因转录变化的数据进行比较，确定了基因表达中一个共同的高置信度变化集合。蛋白质丰度的泛化变化表明，蛋白质水解、戊糖磷酸途径以及氨基酸生物合成的重新组织在应激反应中发挥着作用。