Streptococcus pneumoniae choline kinase (sChoK) has previously been proposed as a drug target, yet the effectiveness of the first and only known inhibitor of sChoK, HC-3, is in the millimolar range. The aim of this study was thus to further validate sChoK as a potential therapeutic target by discovering more powerful sChoK inhibitors. LDH/PK and colorimetric enzymatic assays revealed two promising sChoK inhibitor leads RSM-932A and MN58b that were discovered with IC50 of 0.5 and 150 μM, respectively, and were shown to be 2–4 magnitudes more potent than the previously discovered inhibitor HC-3. Culture assays showed that the minimum inhibitory concentration (MIC) of RSM-932A and MN58b for S. pneumoniae was 0.4 μM and 10 μM, respectively, and the minimum lethal concentration (MLC) was 1.6 μM and 20 μM, respectively. Western blot monitoring of teichoic acid production revealed differential patterns in response to each inhibitor. In addition, both inhibitors possessed a bacteriostatic mechanism of action, and neither interfered with the autolytic effects of vancomycin. Cells treated with MN58b but not RSM-932A were more sensitive to a phosphate induced autolysis with respect to the untreated cells. SEM studies revealed that MN58b distorted the cell wall, a result consistent with the apparent teichoic acid changes. Two novel and more highly potent putative inhibitors of sChoK, MN58b and RSM-932A, were characterized in this study. However, the effects of sChoK inhibitors can vary at the cellular level. sChoK inhibition is a promising avenue to follow in the development of therapeutics for treatment of S. pneumoniae.

肺炎链球菌胆碱激酶 (sChoK) 以前曾被提议作为药物靶点，但第一个也是唯一一个已知的 sChoK 抑制剂 HC-3 的有效性在毫摩尔范围内。因此，本研究的目的是通过发现更强大的 sChoK 抑制剂来进一步验证 sChoK 作为潜在的治疗靶点。LDH/PK 和比色酶分析揭示了两个有希望的 sChoK 抑制剂先导 RSM-932A 和 MN58b，它们的 IC50 分别为 0.5 和 150 μM，并且比之前发现的抑制剂 HC-3 强 2-4 个数量级. 培养测定表明，RSM-932A 和 MN58b 对肺炎链球菌的最小抑制浓度 (MIC)分别为 0.4 μM 和 10 μM，最小致死浓度 (MLC) 分别为 1.6 μM 和 20 μM。磷壁酸生产的蛋白质印迹监测揭示了对每种抑制剂的不同响应模式。此外，两种抑制剂均具有抑菌作用机制，均不干扰万古霉素的自溶作用。与未处理的细胞相比，用 MN58b 而非 RSM-932A 处理的细胞对磷酸盐诱导的自溶更敏感。SEM 研究表明，MN58b 使细胞壁变形，这一结果与磷壁酸的明显变化一致。本研究对两种新型和更高效的 sChoK 抑制剂 MN58b 和 RSM-932A 进行了表征。然而，sChoK 抑制剂的作用可能在细胞水平上有所不同。肺炎链球菌。