Instituto de Biología Molecular y Celular de Rosario (IBR), Consejo Nacional de Investigaciones Científicas y Técnicas, Ocampo y Esmeralda, S2000FHQ Rosario, Argentina.
Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, 2000 Rosario, Argentina.
ACS Infect Dis. 2024 Jun 14;10(6):2172-2182. doi: 10.1021/acsinfecdis.4c00148. Epub 2024 May 9.
Lipoic acid (LA) is an essential cofactor in prokaryotic and eukaryotic organisms, required for the function of several multienzyme complexes such as oxoacid dehydrogenases. Prokaryotes either synthesize LA or salvage it from the environment. The salvage pathway in includes two lipoate-protein ligases, LplA1 and LplA2, as well as the amidotransferase LipL. In this study, we intended to hijack the salvage pathway by LA analogues that are transferred via LplA2 and LipL to the E2 subunits of various dehydrogenases, thereby resulting in nonfunctional enzymes that eventually impair viability of the bacterium. Initially, a virtual screening campaign was carried out to identify potential LA analogues that bind to LplA2. Three selected compounds affected USA300 growth in minimal medium at concentrations ranging from 2.5 to 10 μg/mL. Further analysis of the most potent compound () revealed its transfer to E2 subunits of dehydrogenase complexes and a negative impact on its functionality. Growth impairment caused by treatment was restored by adding products of the lipoate-dependent enzyme complexes. In addition, infected with -treated USA300 demonstrated a significantly expanded lifespan compared to worms infected with untreated bacteria. Our results provide evidence that LA analogues exploiting the LA salvage pathway represent an innovative strategy for the development of novel antimicrobial substances.
硫辛酸（LA）是原核和真核生物的必需辅酶，对于包括氧化羧酸脱氢酶在内的多种多酶复合物的功能至关重要。原核生物要么合成 LA，要么从环境中回收 LA。包括两种脂酰-蛋白连接酶（LplA1 和 LplA2）以及氨酰转移酶 LipL 的回收途径。在这项研究中，我们打算通过通过 LplA2 和 LipL 转移到各种脱氢酶的 E2 亚基的 LA 类似物来劫持回收途径，从而导致非功能性酶，最终损害细菌的生存能力。最初，进行了虚拟筛选活动，以鉴定与 LplA2 结合的潜在 LA 类似物。三种选定的化合物以 2.5 至 10μg/ml 的浓度在最小培养基中影响 USA300 的生长。对最有效化合物（）的进一步分析表明，它被转移到脱氢酶复合物的 E2 亚基，并对其功能产生负面影响。用脂酰依赖酶复合物的产物处理可恢复因处理而导致的生长受损。此外，与未处理细菌相比，用 -处理过的 USA300 感染的线虫的寿命明显延长。我们的研究结果表明，利用 LA 回收途径的 LA 类似物代表了开发新型抗菌物质的创新策略。
