Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China; State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Int J Antimicrob Agents. 2019 Apr;53(4):442-448. doi: 10.1016/j.ijantimicag.2018.11.016. Epub 2018 Nov 23.
The emergence of drug-resistant Gram-negative bacteria is a serious clinical problem that causes increased morbidity and mortality. However, the slow discovery of new antibiotics is unable to meet the need for treating bacterial infections caused by drug-resistant strains. Lipopolysaccharide (LPS) is synthesized in the cytoplasm and transported to the cell envelope by the LPS transport (Lpt) system. LptA and LptC form a complex that transports LPS from the inner membrane to the outer membrane.
This study performed a screen for agents that disrupt the transport of LPS in Gram-negative bacteria Escherichia coli. It established a yeast two-hybrid system to detect LptA-LptC interaction and used this system to identify a compound, IMB-881, that blocks this interaction and shows antibacterial activity.
This study demonstrated that the IMB-881 compound specifically binds to LptA to disrupt LptA-LptC interaction using surface plasmon resonance assay. Overproduction of LptA protein but not that of LptC lowered the antibacterial activity of IMB-881. Strikingly, Escherichia coli cells accumulated 'extra' membrane material in the periplasm and exhibited filament morphology after treatment with IMB-881.
This study successfully identified, by using a yeast two-hybrid system, an antibacterial agent that likely blocks LPS transport in Gram-negative bacteria.
耐药革兰氏阴性菌的出现是一个严重的临床问题，导致发病率和死亡率增加。然而，新抗生素的发现速度缓慢，无法满足治疗耐药菌株引起的细菌感染的需求。脂多糖 (LPS) 在细胞质中合成，并通过 LPS 转运 (Lpt) 系统转运到细胞包膜。LptA 和 LptC 形成一个复合物，将 LPS 从内膜转运到外膜。
本研究针对革兰氏阴性菌大肠杆菌中 LPS 转运的破坏剂进行了筛选。建立了酵母双杂交系统来检测 LptA-LptC 相互作用，并使用该系统鉴定了一种化合物 IMB-881，该化合物能阻断这种相互作用并具有抗菌活性。
本研究表明，表面等离子体共振分析表明，IMB-881 化合物特异性结合 LptA 以破坏 LptA-LptC 相互作用。LptA 蛋白的过表达而不是 LptC 的过表达降低了 IMB-881 的抗菌活性。引人注目的是，大肠杆菌细胞在用 IMB-881 处理后在周质中积累了“额外”的膜材料，并表现出丝状形态。
本研究成功地通过酵母双杂交系统鉴定了一种抗菌剂，该抗菌剂可能在革兰氏阴性菌中阻断 LPS 转运。
