Chemoenzymatic formation of novel aminocoumarin antibiotics by the enzymes CouN1 and CouN7
Chemoenzymatic formation of novel aminocoumarin antibiotics by the enzymes CouN1 and CouN7
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DOI：
10.1021/bi700433v
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发表时间：
2007-07-17
期刊：
影响因子：
2.9
通讯作者：
Garneau-Tsodikova, Sylvie
中科院分区：
文献类型：
--
作者：
Fridman, Micha;Balibar, Carl J.;Garneau-Tsodikova, Sylvie
氨基香豆素类抗生素新生霉素、氯生霉素和香豆霉素A（1）是细菌II型拓扑异构酶DNA促旋酶的高效抑制剂。氯生霉素和香豆霉素A的关键药效团（1），即5-甲基-2-吡咯基羰基部分，靶向GyrB的ATP结合位点。在氯生霉素和香豆霉素A（1）生物合成的后期步骤中，酰基转移酶Clo/CouN7将5-甲基-2-吡咯基羰基从载体蛋白Clo/CouN1转移至L-诺维糖基支架的3'-羟基。我们首先检查了纯化的巯基化结构域蛋白CouN1的底物特异性，其通过磷酸泛酰巯基乙胺基转移酶Sfp使用5-甲基-2-吡咯基羰基部分的多种合成CoA类似物引发。然后通过酰基转移酶CouN7测定酰基-S-CouN1硫酯作为去氨甲酰基新生霉素的3'-OH基团的供体，产生21种具有安装在氨基香豆素支架的诺维阿糖基部分上的杂环酰基的新变体。5-甲基噻吩衍生物的放大产生了对革兰氏阴性和革兰氏阳性细菌都具有活性的化合物。革兰氏阳性菌的最小抑菌浓度与新生霉素相当。
The aminocoumarin antibiotics novobiocin, clorobiocin, and coumermycin A(1) are highly potent inhibitors of the bacterial type II topoisomerase DNA gyrase. The key pharmacophore of both clorobiocin and coumermycin A(1), the 5-methyl-2-pyrrolylcarbonyl moiety, targets the ATP-binding site of GyrB. The 5-methyl-2-pyrrolylcarbonyl group is transferred by the acyltransferases Clo/CouN7 from the carrier proteins Clo/CouN1 to the 3'-hydroxyl of the L-noviosyl scaffold during the late steps of clorobiocin and coumermycin A(1) biosynthesis. We first examined the substrate specificity of the purified thiolation domain protein CouN1 in becoming primed by the phosphopantetheinyltransferase Sfp using a variety of synthetic CoA analogues of the 5-methyl-2-pyrrolylcarbonyl moiety. The acyl-S-CouN1 thioesters were then assayed as donors to the 3'-OH group of descarbamoylnovobiocin by the acyltransferase CouN7, resulting in 21 novel variants with heterocyclic acyl groups installed on the noviosyl moiety of the aminocoumarin scaffold. Scaleup of a 5-methylthiophene derivative yielded a compound with activity against both Gram-negative and Gram-positive bacteria. The minimal inhibitory concentration found for the Gram-positive bacteria was comparable to that of novobiocin.