Ono Bun-ichiro, Kimiduka Hiroko, Kubota Masashi, Okuno Kazuaki, Yabuta Masayuki
Department of Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Kusatsu, Shiga, Japan.
Biosci Biotechnol Biochem. 2007 Feb;71(2):504-12. doi: 10.1271/bbb.60541. Epub 2007 Feb 7.
Recently we found that the cells of Escherichia coli strain BL21 producing a fusion protein, GST-Sup35NM, show a much more rapid decrease in colony-forming ability in the stationary phase than control cells. In this study, it was found that an extract of the cells producing GST-Sup35NM forms fibrous protein polymers containing GST-Sup35NM. In the course of the study, we realized that strain BL21 carried the ompT mutation. We suspected that the deficiency in OmpT protease was responsible for the observed phenotype. To test this, we introduced the wild-type ompT gene into strain BL21, and found that the transformed cells recovered the wild-type phenotype. We concluded that OmpT protease, though known to localize on the cell surface, is involved in protein quality control within the cell.
最近我们发现，产生融合蛋白GST-Sup35NM的大肠杆菌BL21菌株的细胞在稳定期的集落形成能力比对照细胞下降得更快。在本研究中，发现产生GST-Sup35NM的细胞提取物形成了含有GST-Sup35NM的纤维状蛋白质聚合物。在研究过程中，我们意识到BL21菌株携带ompT突变。我们怀疑OmpT蛋白酶的缺陷是观察到的表型的原因。为了验证这一点，我们将野生型ompT基因导入BL21菌株，发现转化后的细胞恢复了野生型表型。我们得出结论，OmpT蛋白酶虽然已知定位于细胞表面，但参与细胞内的蛋白质质量控制。
