Bacterial cell membrane and membrane proteins

The bacterial cell membrane is a vital phospholipid bilayer that functions as a selective permeability barrier and a platform for essential biological processes, including energy production, nutrient transport, and cell wall assembly (Source: NIH, StatPearls). It consists of the cytoplasmic (inner) membrane in all bacteria and an additional outer membrane in Gram-negative species, which contains lipopolysaccharides and porins that regulate drug entry (Source: Wikipedia, 2024). Membrane proteins, such as penicillin-binding proteins (PBPs) and various transporters, are critical for maintaining cellular homeostasis and structural integrity (Source: UniProt). This target is the site of action for several major antibiotic classes; for example, polymyxins target the outer membrane of Gram-negative bacteria, while lipopeptides like daptomycin disrupt the inner membrane of Gram-positive bacteria (Source: PubMed, 2023). Because bacterial membranes contain unique lipids like phosphatidylglycerol that are less prevalent in mammalian cells, they offer a basis for selective toxicity, though clinical use can be limited by side effects such as nephrotoxicity and neurotoxicity (Source: PubChem).

Other names

Bacterial cytoplasmic membraneBacterial envelopePlasma membraneInner membraneOuter membrane

Drugs targeting the bacterial membrane typically act through membrane disruption, pore formation, or the inhibition of membrane-bound enzymes. Polymyxins bind to lipopolysaccharides and phospholipids in the outer membrane of Gram-negative bacteria, leading to increased permeability and cell death. Daptomycin inserts into the cytoplasmic membrane of Gram-positive bacteria in a calcium-dependent manner, causing rapid depolarization and cessation of DNA, RNA, and protein synthesis. Other agents, like beta-lactams, inhibit membrane-anchored penicillin-binding proteins (PBPs) to disrupt cell wall synthesis (Source: StatPearls, PubMed).