肽聚糖
细菌外膜
单元格信封
大肠杆菌
脂多糖
细胞壁
细胞生物学
内膜
细菌细胞结构
突变体
多蛋白复合物
生物
细胞膜
生物化学
化学
细胞
细菌
基因
遗传学
内分泌学
线粒体
作者
Marcin Grabowicz,Dorothee Andres,Matthew D. Lebar,Goran Malojčić,Daniel Kahne,Thomas J. Silhavy
出处
期刊:eLife
[eLife Sciences Publications, Ltd.]
日期:2014-12-31
卷期号:3
被引量:17
摘要
The lipopolysaccharide (LPS) forms the surface-exposed leaflet of the outer membrane (OM) of Gram-negative bacteria, an organelle that shields the underlying peptidoglycan (PG) cell wall. Both LPS and PG are essential cell envelope components that are synthesized independently and assembled by dedicated transenvelope multiprotein complexes. We have identified a point-mutation in the gene for O-antigen ligase (WaaL) in Escherichia coli that causes LPS to be modified with PG subunits, intersecting these two pathways. Synthesis of the PG-modified LPS (LPS*) requires ready access to the small PG precursor pool but does not weaken cell wall integrity, challenging models of precursor sequestration at PG assembly machinery. LPS* is efficiently transported to the cell surface without impairing OM function. Because LPS* contains the canonical vancomycin binding site, these surface-exposed molecules confer increased vancomycin-resistance by functioning as molecular decoys that titrate the antibiotic away from its intracellular target. This unexpected LPS glycosylation fuses two potent pathogen-associated molecular patterns (PAMPs).
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