The α-ketoglutarate/Fe(II)-dependent dioxygenase VldW is responsible for the formation of validamycin B.
The α-ketoglutarate/Fe(II)-dependent dioxygenase VldW is responsible for the formation of validamycin B.
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DOI：
10.1002/cbic.201200464
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发表时间：
2012-10-15
期刊：
影响因子：
3.2
通讯作者：
Mahmud, Taifo
中科院分区：
文献类型：
--
作者：
Almabruk, Khaled H.;Asamizu, Shumpei;Chang, Ada;Varghese, Sheril G.;Mahmud, Taifo
井冈霉素A（1）是吸水链霉菌（Streptomyces hygroscopicus subsp.）柠檬汁。[1，2] 1的抗真菌活性归因于其核心结构井冈羟胺A（4），其由两个假糖单元井冈霉烯胺（7）和井冈霉胺（8）组成（方案1）。市售井冈霉素通常含有约60%井冈霉素A（1）、约15%井冈霉素B（2）和其他次要类似物。与1相比，羟基化类似物2对真菌病原体的活性显著降低。因此，希望在提高1的产率的同时取消2的生产。另一方面，井冈霉素G（3），1的另一种羟基化类似物，具有很大的潜力，可用作抗糖尿病药物伏格列波糖（11）的前体井冈霉醇胺（10）的直接来源。而S.吸湿亚种柠檬苦素的含量极低（占井冈霉素粗品的0.008%），[3]使得从这种天然产物生产伏格列波糖不切实际。虽然1的生物合成已被广泛研究，但羟基化井冈霉素的形成模式尚未清楚地了解。早期的推测表明2和3的形成可能涉及途径中早期环醇中间体的羟基化。[4]然而，没有实验数据支持这一观点。对几株井冈霉素生物合成基因簇进行了鉴定。hymgoscopicus，如S.吸湿亚种jinggangensis 5008和S.吸湿亚种然而，Iimoneus KCCM 11405（IFO 12704）[5，6]提供了研究这些化合物形成模式的新机会。对前者（瓦尔簇）和后者（vld簇）的直接比较表明，两个簇共享有效霉素A生物合成所需的相似基因组（图S1）。[7]然而，没有发现形成2和3的候选基因。为此，我们首先研究了来自S的瓦尔簇内的两个基因（valE和valJ）。吸湿亚种jinggangensis 5008可能参与羟化井冈霉素的形成。ValE和ValJ是同源酶（67%同一性），与α酮戊二酸/Fe（II）依赖性双加氧酶（催化多种氧化转化的非血红素酶）具有高度同一性。这个酶家族催化多种多样的
Validamycin A (1), an antifungal agent used widely as a crop protectant, is the main component of the validamycin complex produced by Streptomyces hygroscopicus subsp. limoneus.[1, 2] The antifungal activity of 1 has been attributed to its core structure, validoxylamine A (4), which consists of two pseudosugar units, valienamine (7) and validamine (8)(Scheme 1). Commercially available validamycin usually contains~ 60% validamycin A (1),~ 15% validamycin B (2), and other minor analogues. In contrast to 1, the hydroxylated analogue 2 is significantly less active against fungal pathogens. Therefore, it is desirable to abolish the production of 2 while increasing the yield of 1. On the other hand, validamycin G (3), another hydroxylated analogue of 1, has great potential to be used as a direct source of valiolamine (10), the precursor of the antidiabetic drug voglibose (11). However, the production yield of 3 by S. hygroscopicus subsp. limoneus is extremely low (0.008% of the crude validamycins),[3] making it impractical to produce voglibose from this natural product. Efforts to control or improve the production of these hydroxylated validamycins have been hampered by the lack of knowledge of their biosynthesis.While the biosynthesis of 1 has been studied extensively, the modes of formation of the hydroxylated validamycins were not clearly understood. Early speculations suggested that the formation of 2 and 3 may involve hydroxylation of early cyclitol intermediates in the pathway.[4] However, no experimental data were available to support that notion. The identification of the biosynthetic gene clusters of validamycin in several strains of S. hygroscopicus, eg, S. hygroscopicus subsp. jinggangensis 5008 and S. hygroscopicus subsp. limoneus KCCM 11405 (IFO 12704),[5, 6] however, provides new opportunities to investigate the modes of formation of these compounds. Direct comparison of the former (the val cluster) and the latter (the vld cluster) has shown that both clusters share similar sets of genes necessary for the biosynthesis of validamycin A (Figure S1).[7] However, no candidate genes for the formation of 2 and 3 were identified. To this end, we first investigated two genes within the val cluster (valE and valJ) from S. hygroscopicus subsp. jinggangensis 5008 that may be involved in the formation of hydroxylated validamycins. ValE and ValJ are homologous enzymes (67% identity) that show high identity to αketoglutarate/Fe (II)-dependent dioxygenases, non-heme enzymes that catalyze a variety of oxidative transformations. This family of enzymes catalyze a diverse array of
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影响因子：
64.8
作者：
Valegård, K;van Scheltinga, ACT;Andersson, I
通讯作者：
Andersson, I
影响因子：
15
作者：
Dong, HJ;Mahmud, T;Floss, HG
通讯作者：
Floss, HG
影响因子：
3.2
作者：
Yin, XH;Zabriskie, TM
通讯作者：
Zabriskie, TM
影响因子：
3.8
作者：
Bredebach, Miriam;Matern, Ulrich;Martens, Stefan
通讯作者：
Martens, Stefan
影响因子：
2.9
作者：
Luo, LS;Pappalardi, MB;Hausinger, RP
通讯作者：
Hausinger, RP