Insights into the bilayer-mediated toppling mechanism of a folate-specific ECF transporter by cryo-EM.
Proc Natl Acad Sci U S A
; 118(34)2021 08 24.
Article
em En
| MEDLINE
| ID: mdl-34408021
ABSTRACT
Energy-coupling factor (ECF)-type transporters are small, asymmetric membrane protein complexes (â¼115 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.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
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Membrana Celular
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Transportadores de Cassetes de Ligação de ATP
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Microscopia Crioeletrônica
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Microdomínios da Membrana
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Ácido Fólico
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Bicamadas Lipídicas
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2021
Tipo de documento:
Article