• Optimal Functioning of the Lipopolysaccharide Transport Bridge Depends on a Ternary Complex Between the Lipocalin YedD and the LptDE Translocon

ABSTRACT: The outer membrane is an efficient permeability barrier that protects Gram-negative bacteria against external assaults including many antibiotics. The unique permeability features of the outer membrane are due to the presence of lipopolysaccharide (LPS) molecules in its outer leaflet. LPS localization relies on the essential Lpt pathway, which forms a protein bridge that conveys LPS molecules from the inner membrane to the outer membrane. On the receiving side are two outer membrane components, LptD and LptE, which form the translocon that inserts LPS molecules in the outer leaflet. Here, we identify the lipocalin YedD as a novel component of the outer membrane LPS translocon. Structural analysis of the YedD-LptDE complex using cryo-electron microscopy reveals that YedD binds LptD to a region between the -barrel and the periplasmic -taco domain, critical for LptD function. The YedD-LptDE complex is functionally relevant: under conditions where the connectivity of the -taco and Lpt bridge is compromised, the absence of YedD leads to decreased cell viability and accumulation of LPS in the inner membrane. Our findings establish YedD as a novel Lpt component required for optimal LPS transport

INSTRUMENT(S): Orbitrap Exploris 240

ORGANISM(S): Escherichia Coli

SUBMITTER: Didier Vertommen  

LAB HEAD: Jean-François Collet

PROVIDER: PXD059551 | Pride | 2025-07-09

REPOSITORIES: Pride