Department of Internal Medicine, Division of Hematology, University of Utah, Salt Lake City, UT 84112, USA.
Department of Microbiology, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
Biomolecules. 2023 Oct 6;13(10):1485. doi: 10.3390/biom13101485.
The final three steps of heme biogenesis exhibit notable differences between di- and mono-derm bacteria. The former employs the protoporphyrin-dependent (PPD) pathway, while the latter utilizes the more recently uncovered coproporphyrin-dependent (CPD) pathway. In order to devise a rapid screen for potential inhibitors that differentiate the two pathways, the genes associated with the protoporphyrin pathway in an YFP strain were replaced with those for the CPD pathway from (SA) through a sliding modular gene replacement recombineering strategy to generate the strain -CPD-YFP. Potential inhibitors that differentially target the pathways were identified by screening compound libraries against the YFP-producing -CPD-YFP strain in comparison to a CFP-producing strain. Using a mixed strain assay, inhibitors targeting either the CPD or PPD heme pathways were identified through a decrease in one fluorescent signal but not the other. An initial screen identified both azole and prodigiosin-derived compounds that were shown to specifically target the CPD pathway and which led to the accumulation of coproheme, indicating that the main target of inhibition would appear to be the coproheme decarboxylase (ChdC) enzyme. In silico modeling highlighted that these inhibitors are able to bind within the active site of ChdC.
血红素生物合成的最后三个步骤在二价和单价细菌之间表现出显著的差异。前者采用原卟啉依赖性(PPD)途径,而后者利用最近发现的粪卟啉依赖性(CPD)途径。为了设计一种快速筛选潜在抑制剂的方法,以区分这两种途径,我们使用滑动模块化基因替换重组酶策略,将与原卟啉途径相关的基因替换为来自 (SA)的 CPD 途径的基因,从而生成了 菌株 -CPD-YFP。通过筛选化合物文库,将其与产生 CFP 的 菌株进行比较,以鉴定针对两种途径的潜在差异作用抑制剂。使用混合菌株测定法,通过减少一种荧光信号但不减少另一种荧光信号,鉴定出针对 CPD 或 PPD 血红素途径的抑制剂。初步筛选鉴定出唑类和灵菌红素衍生化合物,它们能够特异性地靶向 CPD 途径,并导致粪卟啉积累,这表明抑制的主要靶标似乎是粪卟啉脱羧酶(ChdC)酶。计算机建模突出表明,这些抑制剂能够结合到 ChdC 的活性位点内。