LptB-LptF coupling mediates the closure of the substrate-binding cavity in the LptB₂ FGC transporter through a rigid-body mechanism to extract LPS.

ABSTRACT: Lipopolysaccharides (LPS) are essential envelope components in many Gram-negative bacteria and provide intrinsic resistance to antibiotics. LPS molecules are synthesized in the inner membrane and then transported to the cell surface by the LPS transport (Lpt) machinery. In this system, the ATP-binding cassette (ABC) transporter LptB₂ FGC extracts LPS from the inner membrane and places it onto a periplasmic protein bridge through a poorly understood mechanism. Here, we show that residue E86 of LptB is essential for coupling the function of this ATPase to that of its partners LptFG, specifically at the step where ATP binding drives the closure of the LptB dimer and the collapse of the LPS-binding cavity in LptFG that moves LPS to the Lpt periplasmic bridge. We also show that defec

SUBMITTER: Lundstedt EA 

PROVIDER: S-EPMC7529706 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature