Identification and Characterization of sanH and sanI Involved in the Hydroxylation of Pyridyl Residue During Nikkomycin Biosynthesis in Streptomyces ansochromogenes

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• 作者：Zhoujie Xie ; Guoqing Niu ; Rui Li ; Gang Liu and Huarong Tan
• 刊名：Current Microbiology
• 出版年：2007
• 出版时间：December, 2007
• 年：2007
• 卷：55
• 期：6
• 页码：537-542
• 全文大小：256 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Microbiology
  Biotechnology
  
• 出版者：Springer New York
• ISSN：1432-0991

文摘

Nikkomycins are highly potent inhibitors of chitin synthase. The nikkomycin biosynthetic gene cluster has been cloned from Streptomyces asochromogenes. Two cytochrome P450 monooxygenase genes (sanQ, sanH) and one ferredoxin gene (sanI) were found in the cluster. It was reported that SanQ is involved in the hydroxylation of l-His, a key step in 4-formyl-4-imidazolin-2-one base biosynthesis. Here, we have studied the function of sanH and sanI. Disruption of sanH abolished the production of nikkomycin X and Z, but it accumulated one dominant component nikkomycin Lx, which is the nikkomycin X analog lacking the hydroxy group at the pyridyl residue. The sanI disruption mutant accumulated predominantly nikkomycin Lx in addition to nikkomycin X and Z. The nikkomycin production profile of the sanH and sanI double disruption mutant was the same as that of the sanH disruption mutant. These results confirmed that SanH is essential for the hydroxylation of pyridyl residue in nikkomycin biosynthesis of S. ansochromogenes and first demonstrated that SanI is an effective electron donor for SanH, but not for SanQ in vivo.