This entry represents the bacterial lipocalin YedD, an outer membrane lipoprotein found in Enterobacterales. YedD forms a stable 1:1:1 ternary complex with the LptDE translocon, which is responsible for inserting lipopolysaccharide (LPS) into the out ...
This entry represents the bacterial lipocalin YedD, an outer membrane lipoprotein found in Enterobacterales. YedD forms a stable 1:1:1 ternary complex with the LptDE translocon, which is responsible for inserting lipopolysaccharide (LPS) into the outer leaflet of the outer membrane [1]. Structural analysis reveals that YedD binds to the critical hinge region between the beta-barrel and periplasmic beta-taco domains of LptD, with the short N-terminal alpha helix of LptD inserting into YedD's hydrophobic cavity [1]. Although not essential under laboratory conditions, YedD becomes indispensable for cell viability when the Lpt bridge is destabilised or when the LptDE translocon is functionally compromised [1]. YedD thus functions as an optimiser of LPS transport, stabilising the Lpt bridge and ensuring efficient outer membrane biogenesis. YedD adopts the characteristic lipocalin fold, consisting of an eight-stranded antiparallel beta-barrel with a hydrophobic cavity, connected to a short N-terminal 3-10 helix and a C-terminal alpha helix stabilised by a disulphide bond [1]. The protein is expressed under stress conditions including starvation and high osmolarity [1]. YedD is highly conserved within Enterobacterales, including pathogenic species such as Klebsiella pneumoniae and Enterobacter species [1].
LptA/(LptD N-terminal domain) LPS transport protein
This family of proteins are involved in lipopolysaccharide transport across the gram negative inner and outer membranes. The type examples for this family are E. coli LptA Swiss:P0ADV1 and the N-terminal domain of LptD Swiss:P31554.
