Cryo-EM structures of LolCDE reveal the molecular mechanism of bacterial lipoprotein sorting in Escherichia coli
Fig 5
The U-loop maintains the configuration of the substrate-binding cavity.
(A) Top view of the V-shaped cavity showing that the U-Loop (red) interacts with TMs. Residues from both TM1LolE and TM2LolC (in blue) make hydrophobic contacts with the U-Loop (red). (B and C) The 6 residues (S363-I368 of LolE) that consist of the U-Loop and the 7 residues (V349-A355 in LoopLolC) were deleted, respectively. Photo-crosslinking (B) and complementation assays (C) showing that the U-Loop is crucial for LolCDE function. (D and E) Residues (in red stick model) in (A) were substituted with Asp for photo-crosslinking (D) and complementation assays (E) respectively. Data shown in (B to E) are representatives of 3 replicates.