Lipopolysaccharide export system protein LptC (LptC)

Lipopolysaccharide export system protein LptC is a bitopic inner membrane protein essential for transporting lipopolysaccharide (LPS) from the inner membrane to the outer membrane in Gram-negative bacteria, such as Escherichia coli. It forms a tight complex with the ABC transporter LptB2FG, where its single N-terminal transmembrane helix (TM_C) inserts between the transmembrane domains of LptF and LptG, regulating LPS extraction from the outer leaflet of the inner membrane in an ATP-dependent manner. LptC's periplasmic β-jellyroll domain (C-bjr) interacts with LptB2FG and the periplasmic protein LptA, facilitating LPS handover across the periplasmic bridge to the outer membrane translocon LptDE. LPS binds directly to LptC, inducing conformational changes that affect the entire protein, including its N- and C-terminal regions, and enabling dimerization via N-terminal interfaces. This coordinated action ensures efficient, unidirectional LPS transport, critical for outer membrane biogenesis and bacterial antibiotic resistance. While not a human therapeutic target, LptC's role in LPS assembly positions it as a potential antibacterial drug target to disrupt the protective barrier in Gram-negative pathogens.

Other names

LPS transport protein LptCLipopolysaccharide transport protein LptC