Lipid A moiety of lipopolysaccharide (Lipid A)

Lipid A is a structurally conserved glycolipid comprising a β(1→6)-linked disaccharide of glucosamine, phosphorylated and acylated with multiple (usually six) fatty acids and phosphate groups[2][4][7]. It anchors lipopolysaccharide in the bacterial outer membrane and is responsible for most of LPS's toxic effects, triggering innate immune responses via TLR4 and related receptors[1][2][3]. Despite structural variability among bacteria, Lipid A universally contributes to membrane stability and pathogenesis, and has been extensively targeted for antibiotic and immunological intervention[3][5][8]. Modifying its acylation or phosphorylation state profoundly affects its immune activity and potential therapeutic use[3][7].

Other names

Lipid AEndotoxin core (occasionally, imprecise)LPS lipid domainGlycophospholipid moiety of lipopolysaccharide

Neutralization or antagonism of TLR4 activation (e.g., Eritoran); Disruption of outer membrane integrity, leading to bacterial death (e.g., polymyxins); Inhibition of biosynthetic enzymes (e.g., LpxC inhibitors); Immunomodulation as vaccine adjuvant (e.g., monophosphoryl lipid A)