Lipopolysaccharide pyrophosphate moieties (LPS pyrophosphate)

Lipopolysaccharide (LPS) pyrophosphate moieties are essential anionic structural components located within the Lipid A region of the Gram-negative bacterial outer membrane [1]. These negatively charged phosphate groups, typically found at the 1 and 4' positions of the glucosamine backbone, are critical for maintaining the structural integrity of the bacterial cell envelope by facilitating cross-linking with divalent cations such as magnesium and calcium [2]. From a therapeutic perspective, these moieties serve as the primary molecular target for cationic lipopeptide antibiotics, most notably the polymyxins, including Polymyxin B and Colistin [3]. The electrostatic interaction between the positively charged residues of these drugs and the negatively charged LPS phosphate groups displaces the stabilizing divalent cations, leading to a loss of membrane stability, increased permeability, and eventual cell lysis [1, 3]. Additionally, these phosphate groups are vital for the recognition of LPS by the human MD-2/TLR4 receptor complex, which triggers the innate immune response; modifications to these groups, such as the addition of phosphoethanolamine, are a primary mechanism by which bacteria develop resistance to polymyxins and evade host immunity [4, 5]. [1] MacNair, C. R., et al. (2018). Nature Communications. [2] Raetz, C. R., & Whitfield, C. (2002). Annual Review of Biochemistry. [3] Velkov, T., et al. (2013). Journal of Medicinal Chemistry. [4] Park, B. S., et al. (2009). Nature. [5] Liu, Y. Y., et al. (2016). The Lancet Infectious Diseases.

Other names

Lipid A phosphate groupsLPS phosphate moietiesEndotoxin phosphate groupsLipid A 1,4'-bisphosphate

Electrostatic binding to negatively charged phosphate groups, displacement of divalent cations (Mg2+, Ca2+), and subsequent disruption of the bacterial outer membrane.