Proteomic profiling of Mycobacterium tuberculosis identifies nutrient-starvation-responsive toxin-antitoxin systems.
Proteomic profiling of Mycobacterium tuberculosis identifies nutrient-starvation-responsive toxin-antitoxin systems.
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DOI：
10.1074/mcp.m112.018846
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发表时间：
2013-05
期刊：
影响因子：
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通讯作者：
Rosenkrands I
中科院分区：
文献类型：
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作者：
Albrethsen J;Agner J;Piersma SR;Højrup P;Pham TV;Weldingh K;Jimenez CR;Andersen P;Rosenkrands I
为了成功进入潜伏阶段，结核分枝杆菌必须适应营养限制和缺氧等条件。模拟潜伏感染的体外模型是描述细菌以非生长形式存在时发生的代谢变化的有价值的工具。我们使用两种互补的蛋白质组学方法，无标记LC-MS/MS分析和二维差异凝胶电泳，来确定营养饥饿培养的结核分枝杆菌细胞外蛋白的蛋白质组学特征。通过对分离样品进行无标记LC-MS/MS分析，从log phase和营养匮乏培养滤液中鉴定出1176种蛋白质，其中营养匮乏培养滤液中有230种蛋白质水平升高，208种蛋白质水平降低。通过基因本体聚类分析，发现营养饥饿期间整体代谢存在显著差异。值得注意的是，毒素-抗毒素系统的成员在营养匮乏的培养物中大量存在，支持这些全球模块在结核分枝杆菌将其代谢转换为休眠时的作用。参与氨基酸和蛋白质合成的蛋白质丰度明显下降，脂质代谢也发生了变化。对数据集的进一步分析发现，脂蛋白丰度增加，ESAT-6家族蛋白丰度降低。二维差异凝胶电泳蛋白质组学的结果与LC-MS/MS数据总体一致，并对蛋白质降解和修饰提供了补充见解。
In order to successfully enter the latent stage, Mycobacterium tuberculosis must adapt to conditions such as nutrient limitation and hypoxia. In vitro models that mimic latent infection are valuable tools for describing the changes in metabolism that occur when the bacterium exists in a non-growing form. We used two complementary proteomic approaches, label-free LC-MS/MS analysis and two-dimensional difference gel electrophoresis, to determine the proteome profile of extracellular proteins from M. tuberculosis cultured under nutrient starvation. Through the label-free LC-MS/MS analysis of fractionated samples, 1176 proteins were identified from culture filtrates of log phase and nutrient-starved cultures, and the protein levels of 230 proteins were increased in nutrient-starved culture filtrates, whereas those of 208 proteins were decreased. By means of Gene Ontology clustering analysis, significant differences in the overall metabolism during nutrient starvation were detected. Notably, members of the toxin–antitoxin systems were present in larger quantities in nutrient-starved cultures, supporting a role for these global modules as M. tuberculosis switches its metabolism into dormancy. Decreased abundance of proteins involved in amino acid and protein synthesis was apparent, as well as changes in the lipid metabolism. Further analysis of the dataset identified increased abundance of lipoproteins and decreased abundance of ESAT-6 family proteins. Results from the two-dimensional difference gel electrophoresis proteomics demonstrated overall agreement with the LC-MS/MS data and added complementary insights about protein degradation and modification.