Generation of new landomycins with altered saccharide patterns through over-expression of the glycosyltransferase gene lanGT3 in the biosynthetic gene cluster of landomycin A in Streptomyces cyanogenus S-136
Generation of new landomycins with altered saccharide patterns through over-expression of the glycosyltransferase gene lanGT3 in the biosynthetic gene cluster of landomycin A in Streptomyces cyanogenus S-136
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DOI：
10.1002/cbic.200600360
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发表时间：
2007-01-02
期刊：
影响因子：
3.2
通讯作者：
Rohr, Juergen
中科院分区：
文献类型：
--
作者：
Zhu, Lili;Luzhetskyy, Andriy;Rohr, Juergen
两种新的兰多霉素化合物，兰多霉素I和J，产生了一个新的突变株的链霉菌氰，其中的糖基转移酶，是由lanGT 3编码的过表达。该突变体还产生已知的兰德霉素A、B和D。所有这些化合物由相同的聚酮衍生的糖苷配基组成，但它们的糖部分不同，这些糖部分是不同长度的链。发现主要的新代谢产物landmycin J由landomycinone和一个连接的tetrasacharide链组成。结合先前通过LanGT 3突变株（通过靶向基因缺失LanGT 3获得）生产土地霉素E（其含有三种糖）的结果，证实LanGT 3是负责转移土地霉素A生物合成所需的第四种糖的D-橄榄糖基转移酶。实验还表明，基因过表达是一种使生物合成途径失衡以产生新代谢产物的有力方法。通过使用三种不同的肿瘤细胞系评估了新的landomycins与已知的landomycins相比的细胞毒性，并从结果中推导出它们与脱氧糖侧链长度的结构-活性关系（SAR）。
Two novel landoymycin compounds, landomycins I and J, were generated with a new mutant strain of Streptomyces cyanogenus in which the glycosyltransferase that is encoded by lanGT3 was over-expressed. This mutant also produced the known landomycins A, B, and D. All these compounds consist of the same polyketide-derived aglycon but differ in their sugar moieties, which are chains of different lengths. The major new metabolite, landmycin J, was found to consist of landomycinone with a tetrasacharide chain attached. Combined with previous results of the production of landomycin E (which contains three sugars) by the LanGT3- mutant strain (obtained by targeted gene deletion of lanGT3), it was verified that LanGT3 is a D-olivosyltransferase responsible for the transfer of the fourth sugar required for landomycin A biosynthesis. The experiments also showed that gene over-expression is a powerful method for unbalancing biosynthetic pathways in order to generate new metabolites. The cytotoxicity of the new landomycins-compared to known ones-was assessed by using three different tumor cell lines, and their structure-activity relationship (SAR) with respect to the length of the deoxysugar side chain was deduced from the results.