Ekaza E, Teyssier J, Ouahrani-Bettache S, Liautard J P, Köhler S
Institut National de la Santé et de la Recherche Médicale U-431, Université Montpellier II, F-34095 Montpellier, France.
J Bacteriol. 2001 Apr;183(8):2677-81. doi: 10.1128/JB.183.8.2677-2681.2001.
Pathogens often encounter stressful conditions inside their hosts. In the attempt to characterize the stress response in Brucella suis, a gene highly homologous to Escherichia coli clpB was isolated from Brucella suis, and the deduced amino acid sequence showed features typical of the ClpB ATPase family of stress response proteins. Under high-temperature stress conditions, ClpB of B. suis was induced, and an isogenic B. suis clpB mutant showed increased sensitivity to high temperature, but also to ethanol stress and acid pH. The effects were reversible by complementation. Simultaneous inactivation of clpA and clpB resulted in a mutant that was sensitive to oxidative stress. In B. suis expressing gfp, ClpA but not ClpB participated in degradation of the green fluorescent protein at 42 degrees C. We concluded that ClpB was responsible for tolerance to several stresses and that the lethality caused by harsh environmental conditions may have similar molecular origins.
病原体在其宿主内常常会遇到应激条件。为了试图描述猪布鲁氏菌的应激反应，从猪布鲁氏菌中分离出了一个与大肠杆菌clpB高度同源的基因，推导的氨基酸序列显示出应激反应蛋白的ClpB ATP酶家族的典型特征。在高温应激条件下，猪布鲁氏菌的ClpB被诱导，并且一个同源的猪布鲁氏菌clpB突变体对高温、乙醇应激和酸性pH表现出增加的敏感性。通过互补这些效应是可逆的。clpA和clpB的同时失活导致一个对氧化应激敏感的突变体。在表达绿色荧光蛋白（gfp）的猪布鲁氏菌中，ClpA而非ClpB在42℃参与绿色荧光蛋白的降解。我们得出结论，ClpB负责对几种应激的耐受性，并且由恶劣环境条件导致的致死性可能具有相似的分子起源。
