7NNU

Cryo-EM structure of the folate-specific ECF transporter complex in MSP2N2 lipid nanodiscs

Summary for 7NNU

• Entry DOI: 10.2210/pdb7nnu/pdb
• Related: 7NNT
• EMDB information: 12483 12484
• Descriptor: Energy-coupling factor transporter ATP-binding protein EcfA1, Energy-coupling factor transporter ATP-binding protein EcfA2, Conserved hypothetical membrane protein, ... (5 entities in total)
• Functional Keywords: abc transporter, type iii abc transporter, ecf transporter complex, folate transporter, membrane protein, transport protein
• Biological source: Lactobacillus delbrueckii subsp. bulgaricus (strain ATCC 11842 / DSM 20081 / JCM 1002 / NBRC 13953 / NCIMB 11778); More
• Total number of polymer chains: 4
• Total formula weight: 115612.46

Authors

Thangaratnarajah, C.,Rheinberger, J.,Paulino, C.,Slotboom, D.J. (deposition date: 2021-02-25, release date: 2021-08-18, Last modification date: 2024-07-10)

Primary citation

Thangaratnarajah, C.,Rheinberger, J.,Paulino, C.,Slotboom, D.J.
Insights into the bilayer-mediated toppling mechanism of a folate-specific ECF transporter by cryo-EM.
Proc.Natl.Acad.Sci.USA, 118:-, 2021

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 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.

PubMed: 34408021
DOI: 10.1073/pnas.2105014118

Experimental method

ELECTRON MICROSCOPY (2.7 Å)