Structural highlights
Function
[YEBT_ECOLI] Component of a transport pathway that contributes to membrane integrity (PubMed:27795327). May directly span the intermembrane space, facilitating the transport of substrates across the periplasm (Probable).[1] [2]
Publication Abstract from PubMed
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 A 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.
LetB Structure Reveals a Tunnel for Lipid Transport across the Bacterial Envelope.,Isom GL, Coudray N, MacRae MR, McManus CT, Ekiert DC, Bhabha G Cell. 2020 Apr 30;181(3):653-664.e19. doi: 10.1016/j.cell.2020.03.030. PMID:32359438[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Nakayama T, Zhang-Akiyama QM. pqiABC and yebST, Putative mce Operons of Escherichia coli, Encode Transport Pathways and Contribute to Membrane Integrity. J Bacteriol. 2016 Dec 13;199(1). pii: JB.00606-16. doi: 10.1128/JB.00606-16., Print 2017 Jan 1. PMID:27795327 doi:http://dx.doi.org/10.1128/JB.00606-16
- ↑ Ekiert DC, Bhabha G, Isom GL, Greenan G, Ovchinnikov S, Henderson IR, Cox JS, Vale RD. Architectures of Lipid Transport Systems for the Bacterial Outer Membrane. Cell. 2017 Apr 6;169(2):273-285.e17. doi: 10.1016/j.cell.2017.03.019. PMID:28388411 doi:http://dx.doi.org/10.1016/j.cell.2017.03.019
- ↑ Isom GL, Coudray N, MacRae MR, McManus CT, Ekiert DC, Bhabha G. LetB Structure Reveals a Tunnel for Lipid Transport across the Bacterial Envelope. Cell. 2020 Apr 30;181(3):653-664.e19. doi: 10.1016/j.cell.2020.03.030. PMID:32359438 doi:http://dx.doi.org/10.1016/j.cell.2020.03.030
