LapB (YciM) 在调节大肠杆菌脂多糖合成中的双重功能
Sheng Shu1, Yuko Tsutsui1,2, Rajkanwar Nathawat1
1Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520.
概括
适应蛋白 LapB 通过抑制 LpxC 酶活性并将其向降解来调节脂多糖 (LPS) 合成,提供了一个新的抗生素开发策略.
科学领域:
- 微生物学 微生物学
- 结构生物学 结构生物学
- 生物化学 生物化学
背景情况:
- 脂聚糖 (LPS) 合成对格拉姆阴性细菌至关重要,也是抗生素的点.
- 在大肠杆菌中的适应蛋白 LapB (YciM) 通过准 LpxC 进行降解来调节 LPS 合成.
- LpxC是一种脱乙酶,可催化LPS合成中的第一个承诺步骤.
研究的目的:
- 为了阐明LapB介导的LpxC调节的结构机制.
- 研究LapB细胞质域 (LapBcyto) 在LpxC相互作用和降解中的作用.
- 了解LapB在抑制LpxC活性和促进其降解方面的双重作用.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于确定LpxC-LapBcyto复合物的结构.
- 在体外和体内分析以评估突变对LpxC降解的影响.
- 生物化学测试以评估LpxC酶活性.
主要成果:
- 冷-EM结构揭示了LapB如何利用其TPR动机和rubredoxin域来结合LpxC.
- 在LapBcyto/LpxC接口的突变取消了LpxC降解.
- LapBcyto结合异质抑制了LpxC的酶活性.
结论:
- LapB通过两步机制调节LPS合成:初始的LpxC抑制,随后是FtsH介导的降解.
- 这些发现为LapB-LpxC相互作用及其对抗生素开发的影响提供了结构性的见解.
- 通过破坏LPS合成,LapB代表了新型抗菌策略的潜在目标.
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