Lipopolysaccharide of bacterial outer membrane (LPS)

Lipopolysaccharide (LPS) is a large, amphipathic glycolipid complex that forms the outer leaflet of the outer membrane in Gram-negative bacteria. The molecule consists of three distinct regions: lipid A (the hydrophobic anchor responsible for endotoxic activity), a core oligosaccharide, and the O-antigen polysaccharide chain. LPS is critical for structural integrity and viability of Gram-negative bacteria, creating an impermeable barrier against harmful substances, including many antibiotics. It is a major pathogen-associated molecular pattern (PAMP) recognized by the mammalian innate immune system (particularly via Toll-like receptor 4), triggering potent pro-inflammatory responses that can contribute to pathologic conditions such as sepsis and septic shock. LPS structural heterogeneity (especially in O-antigen) underlies serotype classification. Because of its key role in immune activation and as a bacterial survival factor, LPS and its biosynthetic machinery are considered important targets for antibacterial agent development and for sepsis therapeutics, but its non-protein, non-receptor nature presents unique challenges for drug targeting[1][2][3][4][5][6][7].

Other names

bacterial lipopolysaccharideendotoxinLPSlipoglycan

Disruption or neutralization of LPS (e.g., polymyxins bind to lipid A domain, destabilizing the membrane) Inhibition of LPS-induced TLR4 activation (via antagonists) Blocking LPS transport/assembly (antibiotics targeting LPS biogenesis, under research)