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-Structure paper
Title | Insights into the bilayer-mediated toppling mechanism of a folate-specific ECF transporter by cryo-EM. |
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Journal, issue, pages | Proc Natl Acad Sci U S A, Vol. 118, Issue 34, Year 2021 |
Publish date | Aug 24, 2021 |
Authors | Chancievan Thangaratnarajah / Jan Rheinberger / Cristina Paulino / Dirk J Slotboom / |
PubMed Abstract | Energy-coupling factor (ECF)-type transporters are small, asymmetric membrane protein complexes (∼115 kDa) that consist of a membrane-embedded, substrate-binding protein (S component) and a ...Energy-coupling factor (ECF)-type transporters are small, asymmetric membrane protein complexes (∼115 kDa) that consist of a membrane-embedded, substrate-binding protein (S component) and a tripartite ATP-hydrolyzing module (ECF module). They import micronutrients into bacterial cells and have been proposed to use a highly unusual transport mechanism, in which the substrate is dragged across the membrane by a toppling motion of the S component. However, it remains unclear how the lipid bilayer could accommodate such a movement. Here, we used cryogenic electron microscopy at 200 kV to determine structures of a folate-specific ECF transporter in lipid nanodiscs and detergent micelles at 2.7- and 3.4-Å resolution, respectively. The structures reveal an irregularly shaped bilayer environment around the membrane-embedded complex and suggest that toppling of the S component is facilitated by protein-induced membrane deformations. In this way, structural remodeling of the lipid bilayer environment is exploited to guide the transport process. |
External links | Proc Natl Acad Sci U S A / PubMed:34408021 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.7 - 3.4 Å |
Structure data | EMDB-12483, PDB-7nnt: EMDB-12484, PDB-7nnu: |
Chemicals | ChemComp-HOH: |
Source |
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Keywords | TRANSPORT PROTEIN / ABC Transporter / Type III ABC Transporter / ECF transporter complex / Folate transporter / Membrane protein |