9rqi

Cryo-EM structure of Shigella flexneri LptDE bound by phage RBP reveals N-terminal strand insertion into lateral gate

spinqualitylabelsall models 9rqi, resolution 2.76Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 9rqi is a 3 chain structure with sequence from Escherichia phage Oekolampad and Shigella flexneri. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 2.76Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function LPTD_SHIFL Together with LptE, is involved in the assembly of lipopolysaccharide (LPS) at the surface of the outer membrane (By similarity). Publication Abstract from PubMed Bacteriophages are bacterial viruses that provide alternatives to small-molecule drugs to combat infections by antibiotic-resistant bacteria. To infect a bacterial host, a phage needs to bind to the bacterial surface via receptor binding proteins (RBPs), which are critical for determining host specificity. For functionally important receptors, the RBP-receptor interaction could be exploited via phage steering, where emerging bacterial resistance due to receptor modification could make bacteria less fit or virulent. Despite this, relatively little is known about RBP-receptor interactions. Here, we build on the recent discovery of coliphages that have the outer membrane (OM) lipopolysaccharide translocon LptDE as their terminal receptor and show via cryogenic electron microscopy that, surprisingly, the RBP of the small siphophage Oekolampad binds to a hitherto unobserved, open state of LptDE. The open lateral gate of LptD is occupied by a beta-strand peptide originating from the degraded N-terminal jellyroll domain of LptD, suggesting the possibility of LptD inhibition via peptidomimetics. A structure of LptDE in complex with the superinfection exclusion (SE) protein Rtp45 of the Oekolampad-related phage Rtp shows a mechanism of SE where Rtp45-induced conformational changes in LptD resulting from steric clashes preclude RBP binding. Finally, analysis of spontaneous Oekolampad-resistant Escherichia coli mutants identifies mutations in LptD that abolish the LptDE-RBP interaction in vitro. SDS-EDTA sensitivity assays of the mutants show no major OM defects, consistent with largely preserved LptDE function, and suggesting that phage steering via LptDE might be challenging. Small siphophage binding to an open state of the LptDE outer membrane lipopolysaccharide translocon.,Dunbar E, Clark R, Basle A, Allyjaun S, Newman H, Hubbard J, Khalid S, van den Berg B Proc Natl Acad Sci U S A. 2025 Dec 2;122(48):e2516650122. doi: , 10.1073/pnas.2516650122. Epub 2025 Nov 26. PMID:41296721 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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