The emergence of resistance to frontline antibiotics has called for novel strategies to combat serious pathogenic infections. Methicillin-resistant Staphylococcus aureus [MRSA] is one such pathogen. As opposed to traditional antibiotics, bacteriostatic anti-virulent agents disarm MRSA, without exerting pressure, that cause resistance. Herein, we employed a thermophilic Thermotoga maritima tryptophan synthase (TmTrpB1) enzyme followed by an isonitrile synthase and Fe(II)-α-ketoglutarate-dependent oxygenase, in sequence as biocatalysts to produce antivirulent indole vinyl isonitriles. We report on conversion of simple derivatives of indoles to their C3-vinyl isonitriles, as the enzymes employed here demonstrated broader substrate tolerance. In toto, eight distinct L-Tryptophan derived α-amino acids (7) were converted to their bioactive vinyl isonitriles (3) by action of an isonitrile synthase (WelI1) and an Fe(II)-α-ketoglutarate-dependent oxygenase (WelI3) yielding structural variants possessing antivirulence against MRSA. These indole vinyl isonitriles at 10 μg/mL are effective as antivirulent compounds against MRSA, as evidenced through analysis of rabbit blood hemolysis assay. Based on a homology modelling exercise, of enzyme-substrate complexes, we deduced potential three dimensional alignments of active sites and glean mechanistic insights into the substrate tolerance of the Fe(II)-α-ketoglutarate-dependent oxygenase.
一线抗生素耐药性的出现,要求我们采取新的策略来应对严重的病原体感染。耐
甲氧西林金黄色葡萄球菌(MRSA)就是这样一种病原体。与传统抗生素相比,抑菌性抗病毒制剂能解除 MRSA 的威胁,而不会对其造成压力,导致其产生耐药性。在此,我们采用了嗜热的海洋嗜热菌(Thermotoga maritima)
色氨酸合成酶(TmTrpB1)、异腈合成酶和依赖于Fe(II)-α-酮
戊二酸的加氧酶作为
生物催化剂,依次生成抗病毒的
吲哚乙烯基异腈。我们报告了将
吲哚的简单衍
生物转化为其 C3-
乙烯基异腈的情况,因为这里使用的酶具有更广泛的底物耐受性。在异腈合成酶(WelI1)和依赖于Fe(II)-α-酮
戊二酸的加氧酶(WelI3)的作用下,总共有八种不同的
L-色氨酸衍生的
α-氨基酸(7)被转化为具有
生物活性的
乙烯基异腈(3),产生的结构变体对MRSA具有抗病毒作用。这些
吲哚乙烯基异
腈类化合物在 10 μg/mL 的浓度下可作为抗 MRSA 的有效抗病毒化合物,兔血液溶血试验分析证明了这一点。基于酶-底物复合物的同源建模工作,我们推导出了活性位点的潜在三维排列,并从机理上深入了解了依赖
铁(II)-α-酮
戊二酸的加氧酶对底物的耐受性。