Kusano K, Waterman M R, Sakaguchi M, Omura T, Kagawa N
Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, 37232-0146, USA.
Arch Biochem Biophys. 1999 Jul 1;367(1):129-36. doi: 10.1006/abbi.1999.1248.
The antibiotics chloramphenicol (Cm), tetracycline, and erythromycin, which inhibit bacterial protein synthesis and are known to induce the cold shock response, unexpectedly enhance the heterologous expression of P450s and related proteins in Escherichia coli. In contrast, antibiotics that mimic heat shock in E. coli such as puromycin, streptomycin, and kanamycin decrease the expression of the same proteins. A sublethal dose of Cm (1 microgram/ml) effectively enhances the expression of both membrane-bound proteins (microsomal and mitochondrial P450s) and a soluble mitochondrial protein (adrenodoxin) over the range of two- to eightfold. The expression level of N-terminal truncated P450c17 (1600 nmol/liter culture without Cm), for instance, reached 3500 nmol/liter culture by the addition of Cm, approximately 8.4% of the total cellular protein. Cm also enabled expression at useful levels of active P450s previously difficult to express in E. coli. In contrast, the expression of P450scc, a mitochondrial protein, is decreased by Cm but enhanced by ethanol, a powerful elicitor of heat shock response in E. coli. These results show that both the cold shock response induced by some antibiotics and the heat shock response induced by ethanol may lead to enhanced expression of certain heterologous proteins in E. coli. This study also indicates that protein synthesis inhibitors associated with the cold shock response may act as protein synthesis enhancers under certain conditions.
抗生素氯霉素（Cm）、四环素和红霉素可抑制细菌蛋白质合成，且已知能诱导冷休克反应，然而出乎意料的是，它们能增强大肠杆菌中细胞色素P450（P450s）及相关蛋白的异源表达。相比之下，在大肠杆菌中模拟热休克的抗生素，如嘌呤霉素、链霉素和卡那霉素，则会降低相同蛋白的表达。亚致死剂量的Cm（1微克/毫升）在2至8倍的范围内能有效增强膜结合蛋白（微粒体和线粒体P450s）以及可溶性线粒体蛋白（肾上腺皮质铁氧化还原蛋白）的表达。例如，通过添加Cm，N端截短的P450c17（无Cm时为1600纳摩尔/升培养物）的表达水平达到3500纳摩尔/升培养物，约占总细胞蛋白的8.4%。Cm还能使以前在大肠杆菌中难以表达的活性P450s达到有用的表达水平。相比之下，线粒体蛋白P450scc的表达会被Cm降低，但会被乙醇增强，乙醇是大肠杆菌中热休克反应的强效诱导剂。这些结果表明，某些抗生素诱导的冷休克反应和乙醇诱导的热休克反应都可能导致大肠杆菌中某些异源蛋白的表达增强。这项研究还表明，与冷休克反应相关的蛋白质合成抑制剂在某些条件下可能充当蛋白质合成增强剂。
