Bacterial cell membrane and associated biomacromolecules

The bacterial cell membrane is a fundamental phospholipid bilayer that acts as a selective permeability barrier and a scaffold for essential biological processes, including ATP synthesis, nutrient transport, and cell wall assembly (Silhavy et al., 2010; PMID: 20435813). It consists of the cytoplasmic (inner) membrane and, in Gram-negative species, an additional outer membrane characterized by the presence of lipopolysaccharides and porins. This structural complex is a primary target for several classes of antibiotics that exploit differences between bacterial and eukaryotic lipids to achieve selective toxicity. For instance, lipopeptides like daptomycin insert into the Gram-positive membrane, causing rapid depolarization and potassium ion efflux, while polymyxins target the lipid A component of Gram-negative outer membranes (Humphries et al., 2013; PMID: 23536703; Gallardo-Godoy et al., 2016; PMID: 27104371). Because the integrity of the membrane is vital for bacterial viability, its disruption leads to immediate cessation of macromolecular synthesis and cell death. However, therapeutic use is often limited by safety concerns such as nephrotoxicity and myopathy, reflecting the challenge of targeting membrane structures without affecting host cells (Falagas & Kasiakou, 2006; PMID: 16472270).

Other names

Bacterial cytoplasmic membraneBacterial inner membraneBacterial outer membraneBacterial cell envelope

Drugs targeting the bacterial cell membrane typically act through physical disruption of the lipid bilayer, the formation of transmembrane pores, or the depolarization of the membrane potential. For example, polymyxins bind to lipopolysaccharides in Gram-negative bacteria to increase permeability, while daptomycin aggregates in the presence of calcium to create ion-conducting channels in Gram-positive membranes (Gallardo-Godoy et al., 2016; PMID: 27104371; Humphries et al., 2013; PMID: 23536703).