Innovative approach for improvement of an antibiotic- overproducing industrial strain of Streptomyces albus
Innovative approach for improvement of an antibiotic- overproducing industrial strain of Streptomyces albus
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DOI：
10.1128/aem.69.11.6412-6417.2003
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发表时间：
2003-11-01
影响因子：
4.4
通讯作者：
Ochi, K
中科院分区：
文献类型：
--
作者：
Tamehiro, N;Hosaka, T;Ochi, K
我们用一种白色链霉菌菌株进行了研究，该菌株以前曾被培育成能生产工业量（10 mg/ml）的盐霉素，我们证明了引入产生耐药性的突变以进一步改进菌株的功效。在对链霉素（Str（r））、庆大霉素或利福平（Rif（r））耐药的自发分离株中，检测到盐霉素产量增加的突变株的发生率很高（7 - 12%）。最后，我们成功地证明了通过引入三重突变将工业菌株的盐霉素生产率提高了2.3倍。Strr突变体被证明在rpsL基因（编码核糖体蛋白S12）内具有点突变。同样，Rif（r）突变体在rpoB基因（编码RNA聚合酶0亚基）中也有突变。在Strr突变体（S12蛋白中含有K88 R突变）中盐霉素生产率的增加可能是异常蛋白质合成机制的结果。这种畸变可能表现为在静止期细胞中增强的翻译活性，正如我们在poly（U）定向的无细胞翻译系统中所观察到的那样。K88 R突变体核糖体的特征在于在低Mg 2+浓度下增加的70 S复合物稳定性。我们的结论是，这种异常的蛋白质合成能力的Strr突变体，这是70 S复合物的稳定性增加的结果，是负责显着的盐霉素生产的提高。
Working with a Streptomyces albus strain that had previously been bred to produce industrial amounts (10 mg/ml) of salinomycin, we demonstrated the efficacy of introducing drug resistance-producing mutations for further strain improvement. Mutants with enhanced salinomycin production were detected at a high incidence (7 to 12%) among spontaneous isolates resistant to streptomycin (Str(r)), gentamicin, or rifampin (Rif(r)). Finally, we successfully demonstrated improvement of the salinomycin productivity of the industrial strain by 2.3-fold by introducing a triple mutation. The Strr mutant was shown to have a point mutation within the rpsL gene (encoding ribosomal protein S12). Likewise, the Rif(r) mutant possessed a mutation in the rpoB gene (encoding the RNA polymerase 0 subunit). Increased productivity of salinomycin in the Strr mutant (containing the K88R mutation in the S12 protein) may be a result of an aberrant protein synthesis mechanism. This aberration may manifest itself as enhanced translation activity in stationary-phase cells, as we have observed with the poly (U)-directed cell-free translation system. The K88R mutant ribosome was characterized by increased 70S complex stability in low Mg2+ concentrations. We conclude that this aberrant protein synthesis ability in the Strr mutant, which is a result of increased stability of the 70S complex, is responsible for the remarkable salinomycin production enhancement obtained.