Structural highlights
FunctionECFA1_LACDA ATP-binding (A) component of a common energy-coupling factor (ECF) ABC-transporter complex. Unlike classic ABC transporters this ECF transporter provides the energy necessary to transport a number of different substrates. Publication Abstract from PubMedEnergy-coupling factor (ECF)-type transporters are small, asymmetric membrane protein complexes ( approximately 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-A 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. Insights into the bilayer-mediated toppling mechanism of a folate-specific ECF transporter by cryo-EM.,Thangaratnarajah C, Rheinberger J, Paulino C, Slotboom DJ Proc Natl Acad Sci U S A. 2021 Aug 24;118(34):e2105014118. doi: , 10.1073/pnas.2105014118. PMID:34408021[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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