结核分枝杆菌是唯一最重要的全球传染病杀手,也是世界卫生组织开发新抗菌药物的关键优先病原体。结核分枝杆菌DNA促旋酶是抗结核药物的有效靶点,但是目前使用的目标是DNA断裂-团聚,而不是GyrB亚基的ATPase活性。这里,虚拟筛选,随后通过全细胞和酶抑制试验验证,用于从规格化合物文库中鉴定抑制结核分枝杆菌GyrBATP酶活性的候选化合物。这种方法产生了六种化合物:四种咔唑衍生物(1、2、3和8),苯并吲哚衍生物11和吲哚衍生物14。咔唑衍生物可以被认为是结核分枝杆菌DNA促旋酶ATP酶抑制剂的新支架。化合物8、11和14的IC50值(0.26、0.56和0.08μM,分别)抑制结核分枝杆菌DNA促旋酶ATPase活性是5倍,2倍,比已知的DNA促旋酶ATP酶抑制剂novobiocin好16倍。这些化合物对结核分枝杆菌H37Ra生长的MIC值为25.0、3.1和6.2μg/mL,分别,优于新生霉素(MIC>100.0μg/mL)。对接GyrB:抑制剂复合物模型的分子动力学模拟表明,与GyrBAsp79的氢键相互作用对于化合物8、11和14与结核分枝杆菌GyrB的高亲和力结合对于抑制ATPase活性至关重要。这些数据表明,虚拟筛选可以鉴定体外抑制结核分枝杆菌DNA旋转酶ATP酶活性和结核分枝杆菌细菌生长的已知和新的支架。
Mycobacterium tuberculosis is the single most important global infectious disease killer and a World Health Organization critical priority pathogen for development of new antimicrobials. M. tuberculosis DNA gyrase is a validated target for anti-TB agents, but those in current use target DNA breakage-reunion, rather than the ATPase activity of the GyrB subunit. Here, virtual screening, subsequently validated by whole-cell and enzyme inhibition assays, was applied to identify candidate compounds that inhibit M. tuberculosis GyrB ATPase activity from the Specs compound library. This approach yielded six compounds: four carbazole derivatives (1, 2, 3, and 8), the benzoindole derivative 11, and the indole derivative 14. Carbazole derivatives can be considered a new scaffold for M. tuberculosis DNA gyrase ATPase inhibitors. IC50 values of compounds 8, 11, and 14 (0.26, 0.56, and 0.08 μM, respectively) for inhibition of M. tuberculosis DNA gyrase ATPase activity are 5-fold, 2-fold, and 16-fold better than the known DNA gyrase ATPase inhibitor novobiocin. MIC values of these compounds against growth of M. tuberculosis H37Ra are 25.0, 3.1, and 6.2 μg/mL, respectively, superior to novobiocin (MIC > 100.0 μg/mL). Molecular dynamics simulations of models of docked GyrB:inhibitor complexes suggest that hydrogen bond interactions with GyrB Asp79 are crucial for high-affinity binding of compounds 8, 11, and 14 to M. tuberculosis GyrB for inhibition of ATPase activity. These data demonstrate that virtual screening can identify known and new scaffolds that inhibit both M. tuberculosis DNA gyrase ATPase activity in vitro and growth of M. tuberculosis bacteria.