Lipopolysaccharide transport ATP-binding cassette transporter B₂FGC complex (LptB₂FGC complex)

The Lipopolysaccharide transport ATP-binding cassette transporter B₂FGC complex (LptB₂FGC complex) is a multi-protein membrane complex in Gram-negative bacteria, comprising two LptB ATPase domains, two transmembrane domains (LptF and LptG), and a regulatory transmembrane/periplasmic protein LptC[2][3][7][9]. The complex binds and hydrolyzes ATP, powering the extraction of newly synthesized lipopolysaccharide from the inner membrane and channeling it to the periplasmic components of the Lpt system for final delivery to the bacterial cell surface. Structural studies reveal a dynamic substrate-capture mechanism coordinated by ATP-driven rearrangements and regulation by LptC's transmembrane helix. LptB₂FGC is unique among ABC transporters for transporting its substrate out of the membrane rather than across it. It is indispensable for cell viability, making it a validated antibacterial drug target[2][3][7][9]. Novel antibiotics have been shown to bind and block the LptB₂FGC complex, trapping LPS and leading to bacterial death[4].

Other names

LptB₂FG-LptC complexLptB₂FGC transporterLptB₂FGC ABC transporter

Inhibition of ATP binding and hydrolysis to prevent LPS extraction; Blocking the substrate-binding cavity or conformational transitions necessary for LPS transport; Preventing interaction of LptC and other bridge components to halt transport