Proteomics analysis of carbon-starved Mycobacterium smegmatis:: induction of Dps-like protein
Proteomics analysis of carbon-starved Mycobacterium smegmatis:: induction of Dps-like protein
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DOI：
10.1093/protein/15.6.503
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发表时间：
2002-06-01
期刊：
影响因子：
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通讯作者：
Chatterji, D
中科院分区：
文献类型：
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作者：
Gupta, S;Pandit, SB;Chatterji, D
结核分枝杆菌是一种全球成功的病原体，感染了世界三分之一以上的人口。这些细菌具有非凡的能力，可以在宿主体内长期存在而不被免疫系统识别，然后在生命后期重新出现，导致疾病。这种持久性或休眠性杆菌的生理学特征还不是很清楚。一些证据表明，休眠杆菌在营养缺乏的状态下存活，这种状态在基因表达和生理学方面与细菌的静止期相似。在这个假设下，我们研究了耻垢分枝杆菌在碳饥饿条件下的生存，作为分枝杆菌持久性的模型。耻垢分枝杆菌是一种快速生长的菌株，是研究饥饿反应的良好模型。使用基于二维电泳的蛋白质组学方法，我们鉴定了一种在饥饿条件下优先表达的蛋白质。这种蛋白质与称为 Dps（来自饥饿细胞的 DNA 结合蛋白）的蛋白质家族同源，已知 Dps 可以在各种环境压力下保护 DNA，但迄今为止，尚未在分枝杆菌中报道其存在。在表达和纯化该蛋白后，我们观察到它具有非特异性 DNA 结合能力。形成笼状十二聚体结构是Dps的特征。通过比较模型，我们能够证明来自耻垢分枝杆菌的 Dps 可以形成与来自大肠杆菌的 Dps 的晶体结构相似的十二聚体结构。
Mycobacterium tuberculosis is a globally successful pathogen, infecting more than one third of total world's population. These bacteria have the remarkable ability to persist in the host for long periods of time unrecognized by the immune system and then to re-emerge later in life causing the disease. The physiology of such persistent or dormant bacilli is not very well characterized. Some evidence suggests that the dormant bacilli survive in a nutrient-deprived state that is similar to the stationary phase of the bacteria with respect to gene expression and physiology. Under this assumption we have studied the survival of Mycobacterium smegmatis in carbon starvation conditions as a model for mycobacterial persistence. M.smegmatis, being a fast-growing strain, serves as a good model to study starvation responses. Using the two-dimensional electrophoresis-based proteomics approach, we identified a protein which was found to be expressed preferentially under starvation conditions. This protein is homologous to a family of proteins called Dps (DNA binding Protein from Starved cells) that are known to protect DNA under various kinds of environmental stresses and its existence has, so far, not been reported in mycobacteria. Upon expression and purification of this protein, we observed that it has non-specific DNA-binding ability. Formation of a cage-like dodecamer structure is a characteristic feature of Dps. Using comparative modelling we were able to show that Dps from M.smegmatis could form a dodecamer structure similar to the crystal structure of Dps from Escherichia coli.