ORGANIZATION AND FUNCTIONS OF THE ACTVA REGION OF THE ACTINORHODIN BIOSYNTHETIC GENE-CLUSTER OF STREPTOMYCES-COELICOLOR
ORGANIZATION AND FUNCTIONS OF THE ACTVA REGION OF THE ACTINORHODIN BIOSYNTHETIC GENE-CLUSTER OF STREPTOMYCES-COELICOLOR
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DOI：
10.1007/bf00280297
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发表时间：
1991-12-01
期刊：
影响因子：
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通讯作者：
HOPWOOD, DA
中科院分区：
文献类型：
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作者：
CABALLERO, JL;MARTINEZ, E;HOPWOOD, DA
天蓝色链霉菌放线菌红素生物合成基因簇actVA区序列分析显示，该基因簇有6个开放阅读框（ORF），均为同一方向，长度超过5.32 kb。actVA-ORF1 ORF1的蛋白质产物与act簇中其他地方的另一个基因（actII-ORF2）的蛋白质产物非常相似，该基因编码先前参与从菌丝体输出放线菌紫素的跨膜蛋白。这表明这两种基因产物可能在放线菌紫素输出中合作，可能足以使生物体自我保护免受自杀。其他五个ORF中至少有四个涉及C-6和C-8环羟基化反应的控制，缺乏actVA突变体，这些突变体发生在放线菌紫素生物合成途径的中后期。这一结论是通过将actVA突变体遗传作图至actVA-ORF 3和-ORF 5（可能还有-ORF 4），以及通过发现actVA-ORF 2和-ORF 6的蛋白产物与土霉素或四环素基因簇的基因产物之间的强相似性而得出的，所述土霉素或四环素基因簇的基因产物与这些其他芳香族聚酮抗生素的生物合成中的环羟基化反应有关。
Sequence analysis of the actVA region of the actinorhodin biosynthetic gene cluster of Streptomyces coelicolor revealed a succession of six open reading frames (ORFs), all running in the same direction and extending over 5.32 kb. The protein product of actVA-ORF1 ORF1 strongly resembles that of another gene, elsewhere in the act cluster (actII-ORF2), which codes for a trans-membrane protein previously implicated in actinorhodin export from the mycelium. This suggests that the two gene products may co-operate in actinorhodin export, perhaps being sufficient for self-protection of the organism against suicide. At least four of the other five ORFs are implicated in the control of the C-6 and C-8 ring-hydroxylation reactions, lacking in actVA mutants, that occur at middle to late stages in the actinorhodin biosynthetic pathway. This conclusion was reached by genetic mapping of actVA mutants to actVA-ORF3 and -ORF5 (and perhaps -ORF4), and by the finding of strong resemblances between the protein products of actVA-ORF2 and -ORF6 and the products of genes of the oxytetracycline or tetracenomycin gene clusters that have been implicated in ring-hydroxylation reactions in the biosynthesis of these other aromatic polyketide antibiotics.