Graumann P, Marahiel M A
Biochemie, Fachbereich Chemie, Philipps-Universität Marburg, Germany.
Mol Gen Genet. 1997 Feb 27;253(6):745-52. doi: 10.1007/s004380050379.
The major cold shock protein of Bacillus subtilis, CspB, has been shown to affect the level of several cold-induced proteins in B. subtilis after cold shock. Here we show that the expression of CspB in Escherichia coli at 37 degrees C - conditions where the cold shock proteins CspA and CspB of E. coli are not present - resulted in a marked decrease in cellular growth rate and had a profound influence on the pattern of protein synthesis, as revealed by two-dimensional gel electrophoresis. This involves both decreases and increases in the rates of synthesis of specific proteins. Specifically, CspB induction resulted in enhanced beta-galactosidase activity expressed from a transcriptional hns-lacZ fusion. This increase reflects the induction of hns transcription and H-NS synthesis after cold shock, which has been demonstrated to be dependent on CspA in vitro. In contrast, expression of a mutant form of CspB (CspBF15A) that is unable to bind to ssDNA in vitro had no effect on growth rate, pattern of protein synthesis or beta-galactosidase activity. Our data demonstrate a strong influence of CspB on protein synthesis in E. coli and suggest a similar function for CspA in E. coli to that of CspB in B. subtilis.
枯草芽孢杆菌的主要冷休克蛋白CspB已被证明在冷休克后会影响枯草芽孢杆菌中几种冷诱导蛋白的水平。在此我们表明，在37摄氏度时于大肠杆菌中表达CspB（此时大肠杆菌的冷休克蛋白CspA和CspB并不存在），会导致细胞生长速率显著下降，并对蛋白质合成模式产生深远影响，二维凝胶电泳揭示了这一点。这涉及特定蛋白质合成速率的下降和上升。具体而言，CspB的诱导导致从转录hns - lacZ融合体表达的β - 半乳糖苷酶活性增强。这种增加反映了冷休克后hns转录和H - NS合成的诱导，这在体外已被证明依赖于CspA。相反，一种在体外无法与单链DNA结合的CspB突变形式（CspBF15A）的表达对生长速率、蛋白质合成模式或β - 半乳糖苷酶活性没有影响。我们的数据证明了CspB对大肠杆菌中蛋白质合成有强烈影响，并表明大肠杆菌中的CspA与枯草芽孢杆菌中的CspB具有相似功能。
