Microbial cell envelope phosphates and intracellular phosphate-containing macromolecules (None)

Microbial cell envelope phosphates and intracellular phosphate-containing macromolecules represent a broad class of negatively charged structural and functional components essential for microbial life. In Gram-negative bacteria, the phosphate groups of lipopolysaccharides (LPS) are critical for outer membrane stability, as they cross-link with divalent cations to form a rigid barrier (Landman et al., 2008, PMID: 18549750). In Gram-positive bacteria, teichoic acids and lipoteichoic acids contain phosphate-rich repeating units that regulate cell wall expansion and ion sequestration (Swoboda et al., 2010, PMID: 20047345). Intracellularly, the phosphate backbone of DNA and RNA, along with molecules like ATP, are vital for genetic storage and metabolic energy. These anionic sites serve as the primary docking points for cationic antibiotics, such as polymyxins and various antimicrobial peptides (AMPs), which disrupt membrane integrity through electrostatic displacement (Zasloff, 2002, PMID: 11780052). While highly effective against multi-drug resistant pathogens, targeting these broad anionic moieties requires careful dosing to avoid toxicity in human tissues, particularly the kidneys.

Other names

Bacterial surface phosphatesLipopolysaccharide phosphate groupsTeichoic acid phosphatesAnionic microbial lipidsNucleic acid phosphate backbone

Cationic drugs (e.g., polymyxins) bind electrostatically to the negatively charged phosphate groups of lipopolysaccharides (LPS) in Gram-negative bacteria or teichoic acids in Gram-positive bacteria, displacing stabilizing divalent cations (Mg2+ and Ca2+). This displacement leads to increased membrane permeability, leakage of intracellular contents, and eventual cell death. Some antimicrobial peptides also target the phosphate backbone of intracellular DNA or RNA once the membrane is breached.