Gram-negative bacterial outer membrane lipopolysaccharide core (LPS core)

The Gram-negative bacterial outer membrane lipopolysaccharide (LPS) core is a complex oligosaccharide region that links the membrane-anchored lipid A to the peripheral O-antigen [1]. It is structurally divided into an inner core, characterized by unique sugars like 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo), and an outer core composed of more common hexoses [2]. This region is vital for the structural integrity of the bacterial outer membrane and acts as a selective permeability barrier against toxic hydrophobic molecules and host immune factors [2]. Because the inner core is highly conserved across many pathogenic Gram-negative species, it represents a significant target for the development of broad-spectrum antibiotics and neutralizing antibodies [5]. Therapeutic agents such as polymyxins bind to the LPS core and lipid A, displacing stabilizing divalent cations and leading to membrane disruption and bacterial cell death [3]. Despite its potential, targeting the LPS core in clinical settings like sepsis has proven challenging due to the complex inflammatory cascades triggered by endotoxin release [5]. Sources: [1] Raetz & Whitfield (2002) Ann. Rev. Biochem.; [2] Bertani & Ruiz (2018) EcoSal Plus; [3] PubChem (2024) Polymyxin B; [4] NIH/StatPearls (2023) Gram-Negative Bacteria; [5] Opal (2010) Int. J. Med. Microbiol.

Other names

Core oligosaccharideEndotoxin coreLipopolysaccharide inner and outer coreLPS core region

Displacement of divalent cations (Mg2+ and Ca2+) from the LPS core and lipid A, leading to outer membrane destabilization, increased permeability, and eventual cell lysis [3].