oxazolomycin (OZM ) 的顺序分析从 Streptomyces albus JA3453 的 biosynthetic 基因簇揭示了基因, ozmH,编码混合 polyketide 和 non-ribosomal 肽酶。双人脚踏车 ketosynthase (KS ) 领域(KS 10-1 和 KS 10-2) 与已知的 KS 被描绘,他们出现重要相同。用包含调停 RecA 的相应再结合,否定选择标记 sacB 基因,和温度敏感的复制的一个其他的方法,催化三个一组氨基酸半胱氨酸的指导地点的 mutagenesis 在每双人脚踏车 KS 领域 totest 被执行他们在 OZM 生合成玩的功能。产生变异的紧张的 HPLC 团 spectrometry 分析证明 KS 10-2 为 OZM 生合成是必要的,但是 KS 10-1 不是不可缺少的并且可能用作一个冗余的领域。这些结果在复杂 polyketide synthase 证实了一个额外的领域的存在。
Sequence analysis of oxazolomycin (OZM) biosynthetic gene cluster from Streptomyces albus JA3453 revealed a gene, ozmH, encoding a hybrid polyketide and non-ribosomal peptide enzyme. Tandem ketosynthase (KS) domains (KS10-1 and KS10-2) were characterized and they show significant homology with known KSs. Using an alternative method that involves RecA-mediated homologous recombination, the negative selection marker sacB gene, and temperature-sensitive replications, site-directed mutagenesis of the catalytic triad amino acid cysteines were carried out in each of the tandem KS domains to test the function they play in OZM biosynthesis. HPLC-mass spectrometry analysis of the resulting mutant strains showed that KS10-2 is essential for OZM biosynthesis but KS10-1 is not indispensable and might serve as a "edundant" domain. These results confirmed the existence of an "extra domain" in complex polyketide synthase.