Chemoenzymatic Formation of Novel Aminocoumarin Antibiotics by the Enzymes CouN1 and CouN7

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• 作者：Micha Fridman ; Carl J. Balibar ; Tania Lupoli ; Daniel Kahne ; Christopher T. Walsh ; Sylvie Garneau-Tsodikova
• 刊名：Biochemistry
• 出版年：2007
• 出版时间：July 17, 2007
• 年：2007
• 卷：46
• 期：28
• 页码：8462 - 8471
• 全文大小：256K
• 年卷期：v.46,no.28(July 17, 2007)
• ISSN：1520-4995

文摘

The aminocoumarin antibiotics novobiocin, clorobiocin, and coumermycin A₁ are highly potentinhibitors of the bacterial type II topoisomerase DNA gyrase. The key pharmacophore of both clorobiocinand coumermycin A₁, 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 carrierproteins Clo/CouN1 to the 3'-hydroxyl of the L-noviosyl scaffold during the late steps of clorobiocin andcoumermycin A₁ biosynthesis. We first examined the substrate specificity of the purified thiolation domainprotein CouN1 in becoming primed by the phosphopantetheinyltransferase Sfp using a variety of syntheticCoA analogues of the 5-methyl-2-pyrrolylcarbonyl moiety. The acyl-S-CouN1 thioesters were then assayedas donors to the 3'-OH group of descarbamoylnovobiocin by the acyltransferase CouN7, resulting in 21novel 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-negativeand Gram-positive bacteria. The minimal inhibitory concentration found for the Gram-positive bacteriawas comparable to that of novobiocin.