Kroh H E, Simon L D
Waksman Institute, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854.
J Bacteriol. 1990 Oct;172(10):6026-34. doi: 10.1128/jb.172.10.6026-6034.1990.
The genes that encode the subunits of the Clp protease of Escherichia coli, clpA and clpP, appear to be regulated differently from each other. The clpA gene does not seem to be under heat shock control (Y. S. Katayama, S. Gottesman, J. Pumphrey, S. Rudikoff, W. P. Clark, and M. R. Maurizi, J. Biol. Chem. 263:15226-15236, 1988). In contrast, the level of ClpP protein was increased in rpoH+ cells but not in null rpoH cells after an upshift in temperature from 17 to 43 degrees C. The level of ClpP protein in a null dnaK strain was also elevated relative to the level of ClpP protein in an otherwise isogenic dnaK+ strain. In two-dimensional gels, the ClpP protein was located in the position of the previously unidentified heat shock protein F21.5. No protein spot corresponding to F21.5 was present in two-dimensional gels of a null clpP strain. The clpP gene, therefore, appears to be a heat shock gene, expressed in a sigma 32-dependent manner and negatively regulated by DnaK; the product of clpP is the previously unidentified heat shock protein F21.5.
编码大肠杆菌Clp蛋白酶亚基的基因clpA和clpP，其调控方式似乎互不相同。clpA基因似乎不受热休克调控（Y. S. 片山、S. 戈特斯曼、J. 庞弗里、S. 鲁迪科夫、W. P. 克拉克和M. R. 毛里齐，《生物化学杂志》263:15226 - 15236，1988年）。相比之下，在温度从17℃升至43℃后，rpoH⁺细胞中ClpP蛋白水平升高，而在rpoH基因缺失的细胞中则没有升高。与同基因的dnaK⁺菌株相比，dnaK基因缺失菌株中ClpP蛋白水平也有所升高。在二维凝胶电泳中，ClpP蛋白位于先前未鉴定的热休克蛋白F21.5的位置。在clpP基因缺失菌株的二维凝胶电泳中，没有出现对应于F21.5的蛋白斑点。因此，clpP基因似乎是一个热休克基因，以σ32依赖的方式表达，并受DnaK负调控；clpP的产物是先前未鉴定的热休克蛋白F21.5。
