4-Oxo-4-phenyl-but-2-enoates inhibit MenB, the 1,4-dihydroxyl-2-naphthoyl-CoA synthase in the bacterial menaquinone (MK) biosynthesis pathway, through the formation of an adduct with coenzyme A (CoA). Here, we show that the corresponding methyl butenoates have minimum inhibitory concentration (MIC) values as low as 0.35–0.75 μg/mL against drug-sensitive and -resistant strains of Staphylococcus aureus. Mode of action studies on the most potent compound, methyl 4-(4-chlorophenyl)-4-oxobut-2-enoate (1), reveal that 1 is converted into the corresponding CoA adduct in S. aureus cells and that this adduct binds to the S. aureus MenB (saMenB) with a K_d value of 2 μM. The antibacterial spectrum of 1 is limited to bacteria that utilize MK for respiration, and the activity of 1 can be complemented with exogenous MK or menadione. Finally, treatment of methicillin-resistant S. aureus (MRSA) with 1 results in the small colony variant phenotype, and thus 1 phenocopies knockout of the menB gene. Taken together, the data indicate that the antibacterial activity of 1 results from a specific effect on MK biosynthesis. We also evaluated the in vivo efficacy of 1 using two mouse models of MRSA infection. Notably, compound 1 increased survival in a systemic infection model and resulted in a dose-dependent decrease in bacterial load in a thigh infection model, validating MenB as a target for the development of new anti-MRSA candidates.

中文翻译：

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具有抗MRSA体内活性的4-氧代-4-苯基丁-2-烯酸甲酯，抑制细菌Menaquinone生物合成途径中的MenB。

4-氧代-4-苯基-丁-2-烯酸酯通过与辅酶A（CoA）形成加合物，抑制细菌Menaquinone（MK）生物合成途径中的1,4-二羟基-2-萘甲酰CoA合酶MenB。 ）。在这里，我们显示相应的丁烯酸甲酯对金黄色葡萄球菌的药物敏感和耐药菌株的最低抑菌浓度（MIC）值低至0.35–0.75μg/ mL 。对最有效的化合物4-（4-氯苯基）-4-氧代丁-2-烯酸甲酯（1）的作用模式研究表明，在金黄色葡萄球菌细胞中1被转化为相应的CoA加合物，并且该加合物与到金黄色葡萄球菌种MenB（SA的MenB）与ķ _d值为2μM。的抗菌谱1被限制为利用MK对呼吸菌，和活性1可以与外源MK或甲萘醌作为补充。最后，用1处理耐甲氧西林的金黄色葡萄球菌（MRSA）导致小菌落变异表型，因此有1个表型敲除menB基因。两者合计，数据表明1的抗菌活性来自对MK生物合成的特定作用。我们还使用两种MRSA感染小鼠模型评估了1的体内疗效。值得注意的是，化合物1 在全身感染模型中提高了生存率，并导致大腿感染模型中细菌负荷的剂量依赖性降低，从而证实MenB作为开发新型抗MRSA候选药物的目标。