BIOSYNTHESIS OF ANTHRAQUINONES BY INTERSPECIES CLONING OF ACTINORHODIN BIOSYNTHESIS GENES IN STREPTOMYCETES - CLARIFICATION OF ACTINORHODIN GENE FUNCTIONS
BIOSYNTHESIS OF ANTHRAQUINONES BY INTERSPECIES CLONING OF ACTINORHODIN BIOSYNTHESIS GENES IN STREPTOMYCETES - CLARIFICATION OF ACTINORHODIN GENE FUNCTIONS
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DOI：
10.1128/jb.172.9.4816-4826.1990
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发表时间：
1990-09-01
影响因子：
3.2
通讯作者：
FLOSS, HG
中科院分区：
文献类型：
--
作者：
BARTEL, PL;ZHU, CB;FLOSS, HG
Streptomyces galilaeus ATCC 31133和ATCC 31671分别是蒽环类抗生素阿克拉霉素A和2-羟基阿克拉维酮的生产者，当它们用来自天蓝色链霉菌的DNA转化时，形成了蒽醌aloesaponarin II，所述天蓝色链霉菌含有编码放线菌紫素生物合成途径中的早期反应的四个遗传基因座，actI，actIII，actIV和actVII。亚克隆实验表明，只含有actI和actVII位点的2.8-内切酶对XhoI片段是S. galilaeus ATCC 31133。通过8个乙酰辅酶A当量的缩合反应，然后通过[1，2 - 13 C2]乙酸酯进料实验证明脱羧反应合成了芦荟皂苷II。S. actVI阻断突变体coelicolor B22和B159也形成了aloesaponarin II作为明显的分流产物。S.在放线菌紫素生物合成中的几个其他步骤中被阻断的腔棘鱼不能合成芦荟皂苷II或其他可检测到的蒽醌。当S.用携带actI、actIII和atVII基因座的DNA转化galilaeus ATCC 31671，重组菌株产生芦荟皂苷II和aklavinone，表明放线菌紫素生物合成DNA编码能够将2-羟基aklavinone脱乙酰为aklavinone的功能。当S.用仅携带完整actIII基因（pANT 45）的质粒aklavinone转化galilaeus ATCC 31671。是专门成立的。这些实验表明了actIII基因的功能，其是将C-9处的酮基从组装的聚酮化合物的羧基末端还原为相应的仲醇。在actIII基因的存在下，由于脱水和芳构化而形成的蒽醌或蒽环类在酮还原酶作用的碳上缺乏氧功能。当S.用携带actI、actVII和actIV基因座的DNA转化galilaeus ATCC 31671，重组菌株产生两种新的蒽醌，即芦荟皂苷II的3-羟基类似物脱氧赤紫胶素和1-O-甲基脱氧赤紫胶素。这些实验结果与早期的数据一起提示了放线菌紫素及其相关化合物的生物合成途径。天蓝色。
Streptomyces galilaeus ATCC 31133 and ATCC 31671, producers of the anthracyclines aclacinomycin A and 2-hydroxyaklavinone, respectively, formed an anthraquinone, aloesaponarin II, when they were transformed with DNA from Streptomyces coelicolor containing four genetic loci, actI, actIII, actIV, and actVII, encoding early reactions in the actinorhodin biosynthesis pathway. Subcloning experiments indicated that 2.8-kilobase-pair XhoI fragment containing only the actI and actVII loci was necessary for aloesaponarin II biosynthesis by S. galilaeus ATCC 31133. Aloesaponarin II was synthesized via the condensation of 8 acetyl coenzyme A equivalents, followed by a decarboxylation reaction as demonstrated by [1,2-13C2]acetate feeding experiments. S. coelicolor B22 and B159, actVI blocked mutants, also formed aloesaponarin II as an apparent shunt product. Mutants of S. coelicolor blocked in several otehr steps in actinorhodin biosynthesis did not synthesize aloesaponarin II or other detectable anthraquinones. When S. galilaeus ATCC 31671 was transformed with the DNA carrying the actI, actIII, and atVII loci, the recombinant strain produced both aloesaponarin II and aklavinone, suggesting that the actinorhodin biosynthesis DNA encoded a function able to deoxygenate 2-hydroxyaklavinone to aklavinone. When S. galilaeus ATCC 31671 was transformed with a plasmid carrying only the intact actIII gene (pANT45), aklavinone. was formed exclusively. These experiments indicate a function for the actIII gene, which is the reduction of the keto group at C-9 from the carboxy terminus of the assembled polyketide to the corresponding secondary alcohol. In the presence of the actIII gene, anthraquinones or anthracyclines formed as a result of dehydration and aromatization lack an oxygen function on the carbon on which the keto reductase operated. When S. galilaeus ATCC 31671 was transformed with the DNA carrying the actI, actVII, and actIV loci, the recombinant strain produced two novel anthraquinones, desoxyerythrolaccin, the 3-hydroxy analog of aloesaponarin II, and 1-O-methyldesoxyerythrolaccin. The results obtained in these experiments together with earlier data suggest a pathway for the biosynthesis of actinorhodin and related compounds by S. coelicolor.