Phosphatidylglycerol-rich Gram-positive bacterial membrane

The Phosphatidylglycerol-rich Gram-positive bacterial membrane is the essential lipid bilayer that serves as the primary permeability barrier for Gram-positive bacteria, distinguished by its high content of anionic phospholipids like phosphatidylglycerol (PG) and cardiolipin (Epand et al., 2007, Chem. Phys. Lipids). This structure is vital for maintaining the proton motive force, regulating osmotic pressure, and anchoring proteins involved in cell wall synthesis and nutrient transport (Strahl & Hamoen, 2010, Proc. Natl. Acad. Sci.). In clinical medicine, this membrane is a critical therapeutic target because its negative charge differs significantly from the zwitterionic, cholesterol-rich membranes of mammalian cells, allowing for selective toxicity (Malanovic & Lohner, 2016, Biochim. Biophys. Acta). Lipopeptide antibiotics, most notably daptomycin, target this membrane by binding to PG in a calcium-dependent manner, leading to membrane insertion, depolarization, and rapid cell death (Taylor & Palmer, 2016, Antioxid. Redox Signal.). Resistance often arises through the modification of PG into lysyl-phosphatidylglycerol by the enzyme MprF, which reduces the membrane's net negative charge and repels cationic antibiotics (Ernst & Peschel, 2011, Int. J. Med. Microbiol.). Understanding this target is crucial for treating serious infections caused by pathogens such as Staphylococcus aureus and Enterococcus species.

Other names

Gram-positive bacterial cytoplasmic membraneBacterial cytoplasmic membranePG-rich bacterial membraneAnionic bacterial lipid bilayer

Calcium-dependent binding to phosphatidylglycerol, insertion into the lipid bilayer, formation of oligomeric complexes, and induction of rapid depolarization through ion leakage (primarily potassium), which leads to the inhibition of DNA, RNA, and protein synthesis (Humphries et al., 2013, Clin. Microbiol. Rev.; Taylor & Palmer, 2016, Antioxid. Redox Signal.).