Bacterial cell membrane and cell wall anionic sites

Bacterial cell membrane and cell wall anionic sites are essential structural components that provide a net negative charge to the bacterial surface, facilitating ion homeostasis and environmental protection (Silhavy et al., 2010, Cold Spring Harb Perspect Biol). In Gram-negative bacteria, these sites are primarily the phosphate groups of lipopolysaccharides (LPS), while in Gram-positive bacteria, they include teichoic acids and anionic phospholipids like phosphatidylglycerol (Yeaman & Yount, 2003, Pharmacol Rev). These negatively charged regions serve as the primary docking sites for cationic antimicrobial peptides (CAMPs) and specific antibiotic classes such as polymyxins and lipopeptides (Velkov et al., 2013, J Med Chem). For instance, polymyxins bind to the lipid A portion of LPS through electrostatic interactions, displacing divalent cations and destabilizing the outer membrane (Trimble et al., 2016, Cold Spring Harb Perspect Med). Daptomycin, a lipopeptide, targets anionic phospholipids in the cytoplasmic membrane in a calcium-dependent manner, leading to membrane depolarization and cell death (Humphries et al., 2013, Clin Microbiol Rev). Targeting these sites is a key strategy for treating multi-drug resistant (MDR) infections, although resistance mechanisms, such as the modification of LPS by the mcr gene product, pose significant therapeutic challenges (Liu et al., 2016, Lancet Infect Dis).

Other names

Bacterial anionic surfacesNegatively charged bacterial cell envelopeAnionic phospholipidsLipopolysaccharide phosphate groupsTeichoic acid anionic sites

Cationic antimicrobial agents utilize electrostatic attraction to bind to negatively charged (anionic) components of the bacterial cell envelope. In Gram-negative bacteria, polymyxins bind to the phosphate groups of lipopolysaccharide (LPS), displacing magnesium and calcium ions that normally stabilize the membrane, leading to increased permeability and cell lysis (Poirel et al., 2017, Clin Microbiol Rev). In Gram-positive bacteria, daptomycin interacts with anionic phospholipids like phosphatidylglycerol in the presence of calcium ions, causing membrane insertion, oligomerization, and the formation of pores that leak potassium, resulting in rapid depolarization and inhibition of DNA, RNA, and protein synthesis (Bayer et al., 2013, Ann N Y Acad Sci).