Inhibition of Streptococcus pneumoniae growth by masarimycin
Inhibition of Streptococcus pneumoniae growth by masarimycin
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DOI：
10.1099/mic.0.001182
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发表时间：
2022-04-01
期刊：
影响因子：
2.8
通讯作者：
Reid，Christopher W.
中科院分区：
文献类型：
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作者：
Haubrich，Brad A.;Nayyab，Saman;Reid，Christopher W.
尽管重新燃起了人们的兴趣，但与一般的糖生物学领域相比，研究肽聚糖代谢的化学生物学方法的发展滞后。为了解决这个问题，筛选了一组抗革兰氏阳性细菌肺炎链球菌的二胺，以确定细菌生长的抑制剂。筛选结果表明，二胺马沙霉素是一种抑菌抑制剂。MIC为8µM的肺炎生长。二胺以浓度依赖的方式抑制洗涤剂诱导的自溶，表明扰动肽聚糖降解是其作用方式。基于细胞筛选马沙利霉素对抗一组自溶素突变体，发现对缺乏参与细胞分裂的内切- n -乙酰氨基葡萄糖酶ΔlytBstrain具有较高的MIC。随后的生化和表型分析表明，较高的MIC是由于与LytB的间接相互作用。进一步分析马沙霉素处理细胞的细胞表面变化，发现了几种月光蛋白的过度表达，包括与调节细胞形状有关的延伸因子Tu。使用马沙林霉素和其他抗生素进行的棋盘试验确定了与靶向抗生素磷霉素的细胞壁的拮抗关系，这进一步支持了细胞壁的作用模式。
Despite renewed interest, development of chemical biology methods to study peptidoglycan metabolism has lagged in comparison to the glycobiology field in general. To address this, a panel of diamides were screened against the Gram-positive bacteriumStreptococcus pneumoniaeto identify inhibitors of bacterial growth. The screen identified the diamide masarimycin as a bacteriostatic inhibitor ofS. pneumoniaegrowth with an MIC of 8 µM. The diamide inhibited detergent-induced autolysis in a concentration-dependent manner, indicating perturbation of peptidoglycan degradation as the mode-of-action. Cell based screening of masarimycin against a panel of autolysin mutants, identified a higher MIC against a ΔlytBstrain lacking an endo-N-acetylglucosaminidase involved in cell division. Subsequent biochemical and phenotypic analyses suggested that the higher MIC was due to an indirect interaction with LytB. Further analysis of changes to the cell surface in masarimycin treated cells identified the overexpression of several moonlighting proteins, including elongation factor Tu which is implicated in regulating cell shape. Checkerboard assays using masarimycin in concert with additional antibiotics identified an antagonistic relationship with the cell wall targeting antibiotic fosfomycin, which further supports a cell wall mode-of-action.