Gram-negative bacterial inner membrane (IM)

The Gram-negative bacterial inner membrane is a symmetric phospholipid bilayer that serves as the primary hydrophobic barrier between the cytoplasm and the periplasmic space. It is composed mainly of phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin, and it houses the machinery for oxidative phosphorylation, active transport, and lipid biosynthesis (Sohlenkamp & Geiger, 2016, FEMS Microbiology Reviews). This membrane is essential for maintaining the proton motive force required for ATP production and flagellar rotation. As a therapeutic target, it is susceptible to membrane-active agents like polymyxins and various antimicrobial peptides which disrupt the bilayer's structural integrity (Trimble et al., 2016, Cold Spring Harbor Perspectives in Medicine). Such disruption leads to the rapid leakage of essential ions and metabolites, resulting in bacterial cell death. While highly effective against multidrug-resistant pathogens, targeting the inner membrane requires high selectivity to avoid damaging host cell membranes. Cross-reactivity with eukaryotic membranes can lead to significant systemic toxicities, such as nephrotoxicity and neurotoxicity (Epand et al., 2016, Journal of Peptide Science). Understanding the unique lipid composition of the bacterial inner membrane is crucial for the development of next-generation antibiotics that can bypass outer membrane defenses.

Other names

Bacterial cytoplasmic membraneBacterial plasma membraneInner membraneBacterial phospholipid bilayer

Disruption of membrane integrity, induction of pore formation, and dissipation of the proton motive force leading to cytoplasmic leakage and cell death.