Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclydegrid.11984.35, Glasgow, UK.
Institute of Infection, Immunity and Inflammation, University of Glasgowgrid.8756.c, Glasgow, UK.
Appl Environ Microbiol. 2022 Aug 9;88(15):e0069222. doi: 10.1128/aem.00692-22. Epub 2022 Jul 18.
The global increase in antimicrobial-resistant infections means that there is a need to develop new antimicrobial molecules and strategies to combat the issue. Aurodox is a linear polyketide natural product that is produced by Streptomyces goldiniensis, yet little is known about aurodox biosynthesis or the nature of the biosynthetic gene cluster (BGC) that encodes its production. To gain a deeper understanding of aurodox biosynthesis by S. goldiniensis, the whole genome of the organism was sequenced, revealing the presence of an 87 kb hybrid polyketide synthase/non-ribosomal peptide synthetase (PKS/NRPS) BGC. The aurodox BGC shares significant homology with the kirromycin BGC from S. collinus Tϋ 365. However, the genetic organization of the BGC differs significantly. The candidate aurodox gene cluster was cloned and expressed in a heterologous host to demonstrate that it was responsible for aurodox biosynthesis and disruption of the primary PKS gene () abolished aurodox production. These data supported a model whereby the initial core biosynthetic reactions involved in aurodox biosynthesis followed that of kirromycin. Cloning from S. goldiniensis and expressing this in the kirromycin producer S. collinus Tϋ 365 enabled methylation of the pyridone group, suggesting this is the last step in biosynthesis. This methylation step is also sufficient to confer the unique type III secretion system inhibitory properties to aurodox. Enterohemorrhagic Escherichia coli (EHEC) is a significant global pathogen for which traditional antibiotic treatment is not recommended. Aurodox inhibits the ability of EHEC to establish infection in the host gut through the specific targeting of the type III secretion system while circumventing the induction of toxin production associated with traditional antibiotics. These properties suggest aurodox could be a promising anti-virulence compound for EHEC, which merits further investigation. Here, we characterized the aurodox biosynthetic gene cluster from Streptomyces goldiniensis and established the key enzymatic steps of aurodox biosynthesis that give rise to the unique anti-virulence activity. These data provide the basis for future chemical and genetic approaches to produce aurodox derivatives with increased efficacy and the potential to engineer novel elfamycins.
全球范围内对抗微生物药物耐药性感染的需求不断增加，这意味着需要开发新的抗菌分子和策略来应对这一问题。Aurodox 是一种由金色链霉菌产生的线性聚酮天然产物，但人们对 aurodox 的生物合成或编码其产生的生物合成基因簇（BGC）的性质知之甚少。为了更深入地了解金色链霉菌的 aurodox 生物合成，我们对该生物体的整个基因组进行了测序，揭示了一个 87kb 的混合聚酮合酶/非核糖体肽合酶（PKS/NRPS） BGC 的存在。aurodox BGC 与来自 S. collinus Tϋ 365 的 kirromycin BGC 具有显著同源性。然而，BGC 的遗传组织有很大的不同。候选的 aurodox 基因簇被克隆并在异源宿主中表达，证明它负责 aurodox 的生物合成，并且破坏主要的 PKS 基因（）会阻止 aurodox 的产生。这些数据支持了一个模型，即 aurodox 生物合成的初始核心生物合成反应遵循 kirromycin 的生物合成。从金色链霉菌中克隆并在 kirromycin 产生菌 S. collinus Tϋ 365 中表达可以使吡啶酮基团甲基化，这表明这是生物合成的最后一步。该甲基化步骤足以赋予 aurodox 独特的 III 型分泌系统抑制特性。肠出血性大肠杆菌（EHEC）是一种重要的全球病原体，不建议对其进行传统抗生素治疗。Aurodox 通过特异性靶向 III 型分泌系统抑制 EHEC 在宿主肠道中建立感染的能力，同时避免了与传统抗生素相关的毒素产生的诱导。这些特性表明 aurodox 可能是一种有前途的 EHEC 抗毒力化合物，值得进一步研究。在这里，我们从金色链霉菌中鉴定了 aurodox 的生物合成基因簇，并确定了 aurodox 生物合成的关键酶促步骤，这些步骤产生了独特的抗毒力活性。这些数据为未来使用化学和遗传方法生产具有更高疗效和潜在能力的 aurodox 衍生物以及设计新型 elfamycins 提供了基础。
