Summary for 9IA2
| Entry DOI | 10.2210/pdb9ia2/pdb |
| EMDB information | 52778 |
| Descriptor | LPS-assembly protein LptD, LPS-assembly lipoprotein LptE, LPS-assembly lipoprotein LptM (3 entities in total) |
| Functional Keywords | lipopolysaccharide transport, transport protein |
| Biological source | Escherichia coli More |
| Total number of polymer chains | 3 |
| Total formula weight | 119425.60 |
| Authors | |
| Primary citation | Chen, H.,Siroy, A.,Morales, V.,Gurvic, D.,Quentin, Y.,Balor, S.,Abuta'a, Y.A.,Marteau, M.,Froment, C.,Caumont-Sarcos, A.,Marcoux, J.,Stansfeld, P.J.,Fronzes, R.,Ieva, R. Structural basis of lipopolysaccharide assembly by the outer membrane translocon holo-complex. Nat Commun, 16:10404-10404, 2025 Cited by PubMed Abstract: Lipopolysaccharide (LPS) assembly at the surfaces-exposed leaflet of the bacterial outer membrane (OM) is mediated by the OM LPS translocon. An essential transmembrane β-barrel protein, LptD, and a cognate lipoprotein, LptE, translocate LPS selectively into the OM external leaflet via a poorly understood mechanism. Here, we characterize two additional translocon subunits, the lipoproteins LptM and LptY (formerly YedD). We use single-particle cryo-EM analysis, functional assays and molecular dynamics simulations to visualize the roles of LptM and LptY at the translocon holo-complex LptDEMY, uncovering their impact on LptD conformational dynamics. Whereas LptY binds and stabilizes the periplasmic LptD β-taco domain that functions as LPS receptor, LptM intercalates the lateral gate of the β-barrel domain, promoting its opening and access by LPS. Remarkably, we demonstrate a conformational switch of the LptD β-taco/β-barrel interface alternating between contracted and extended states. β-strand 1 of LptD, which defines the mobile side of the lateral gate, binds LPS and performs a stroke movement toward the external leaflet during the contracted-to-extended state transition. Our findings support a detailed mechanistic framework explaining the selective transport of LPS to the membrane external leaflet. PubMed: 41285762DOI: 10.1038/s41467-025-65370-2 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (2.47 Å) |
Structure validation
Download full validation report
