6V0E
Lipophilic Envelope-spanning Tunnel B (LetB), Model 3
Summary for 6V0E
| Entry DOI | 10.2210/pdb6v0e/pdb |
| EMDB information | 20995 |
| Descriptor | Intermembrane transport protein YebT (1 entity in total) |
| Functional Keywords | conformational dynamics, lipid transport, bacterial cell envelope, letb, yebt, mce |
| Biological source | Escherichia coli (strain K12) |
| Total number of polymer chains | 6 |
| Total formula weight | 538464.19 |
| Authors | Isom, G.L.,Coudray, N.,MacRae, M.R.,McManus, C.T.,Ekiert, D.C.,Bhabha, G. (deposition date: 2019-11-18, release date: 2020-05-06, Last modification date: 2024-03-06) |
| Primary citation | Isom, G.L.,Coudray, N.,MacRae, M.R.,McManus, C.T.,Ekiert, D.C.,Bhabha, G. LetB Structure Reveals a Tunnel for Lipid Transport across the Bacterial Envelope. Cell, 181:653-664.e19, 2020 Cited by PubMed Abstract: Gram-negative bacteria are surrounded by an outer membrane composed of phospholipids and lipopolysaccharide, which acts as a barrier and contributes to antibiotic resistance. The systems that mediate phospholipid trafficking across the periplasm, such as MCE (Mammalian Cell Entry) transporters, have not been well characterized. Our ~3.5 Å cryo-EM structure of the E. coli MCE protein LetB reveals an ~0.6 megadalton complex that consists of seven stacked rings, with a central hydrophobic tunnel sufficiently long to span the periplasm. Lipids bind inside the tunnel, suggesting that it functions as a pathway for lipid transport. Cryo-EM structures in the open and closed states reveal a dynamic tunnel lining, with implications for gating or substrate translocation. Our results support a model in which LetB establishes a physical link between the two membranes and creates a hydrophobic pathway for the translocation of lipids across the periplasm. PubMed: 32359438DOI: 10.1016/j.cell.2020.03.030 PDB entries with the same primary citation |
| Experimental method | ELECTRON MICROSCOPY (3.06 Å) |
Structure validation
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