The granaticin biosynthetic gene cluster of Streptomyces violaceoruber Tu22: sequence analysis and expression in a heterologous host
The granaticin biosynthetic gene cluster of Streptomyces violaceoruber Tu22: sequence analysis and expression in a heterologous host
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DOI：
10.1016/s1074-5521(98)90292-7
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发表时间：
1998-11-01
影响因子：
--
通讯作者：
Hopwood, DA
中科院分区：
文献类型：
--
作者：
Ichinose, K;Bedford, DJ;Hopwood, DA
简介：granaticins 是苯并异色满醌类芳香族聚酮化合物的成员，其中最著名的成员是由天蓝色链霉菌 A3(2) 产生的放线菌素。此类化合物的遗传分析在有关芳香族聚酮合酶 (PKS) 控制产物结构的方式的假设的发展中发挥了重要作用。尽管格拉提辛新生聚酮化合物与放线菌素相同，但 PKS 后步骤涉及不同的吡喃环立体化学和糖基化。因此，两种代谢物的完整基因簇的比较非常有意义。 结果：来自紫色链霉菌 Tu22 的整个granaticin 基因簇（gra 簇）被克隆到两个重叠粘粒中的任一个上，并在异源宿主天蓝色链霉菌 A3(2) 菌株 CH999 中表达。重组菌株的化学分析表明产生了granaticin、granaticin B、二氢granaticin和二氢granaticin B，它们是S. violaceoruber的四种已知代谢物。对其中一个粘粒 pOJ466-22-24 的插入片段的完整 39,250 个碱基对序列进行分析，揭示了 37 个完整的开放阅读框 (ORF)，其中 15 个类似于来自 S. coelicolor A3(2) 的 actinorhodin 基因簇的 ORF。其中，有九个类似的 ORF 可能参与链霉菌属的脱氧糖代谢。结论：基于这些相似性，对大多数新发现的 ORF 的产物进行了假定的功能分配，包括参与 PKS 的基因和格拉提辛苷元生物合成中的定制步骤、脱氧糖途径中的步骤以及假定的调节和输出功能。
Introduction: The granaticins are members of the benzoisochromanequinone class of aromatic polyketides, the best known member of which is actinorhodin made by Streptomyces coelicolor A3(2). Genetic analysis of this class of compounds has played a major role in the development of hypotheses about the way in which aromatic polyketide synthases (PKSs) control product structure. Although the granaticin nascent polyketide is identical to that of actinorhodin, post-PKS steps involve different pyran-ring stereochemistry and glycosylation. Comparison of the complete gene clusters for the two metabolites is therefore of great interest.Results: The entire granaticin gene cluster (the gra cluster) from Streptomyces violaceoruber Tu22 was cloned on either of two overlapping cosmids and expressed in the heterologous host, Streptomyces coelicolor A3(2), strain CH999. Chemical analysis of the recombinant strains demonstrated production of granaticin, granaticin B, dihydrogranaticin and dihydrogranaticin B, which are the four known metabolites of S. violaceoruber. Analysis of the complete 39,250 base pair sequence of the insert of one of the cosmids, pOJ466-22-24, revealed 37 complete open reading frames (ORFs), 15 of which resemble ORFs from the act (actinorhodin) gene cluster of S. coelicolor A3(2). Among the rest, nine resemble ORFs potentially involved in deoxysugar metabolism from Streptomyces spp. and other bacteria, and six resemble regulatory ORFs.Conclusions: On the basis of these resemblances, putative functional assignments of the products of most of the newly discovered ORFs were made, including those of genes involved in the PKS and tailoring steps in the biosynthesis of the granaticin aglycone, steps in the deoxy sugar pathway, and putative regulatory and export functions.