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Proton-coupled sugar transport in the prototypical major facilitator superfamily protein XylE

The major facilitator superfamily (MFS) is the largest collection of structurally related membrane proteins that transport a wide array of substrates. The proton-coupled sugar transporter XylE is the first member of the MFS that has been structurally characterized in multiple transporting conformati...

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Detalles Bibliográficos
Autores principales: Wisedchaisri, Goragot, Park, Min-Sun, Iadanza, Matthew G., Zheng, Hongjin, Gonen, Tamir
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Pub. Group 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4137407/
https://www.ncbi.nlm.nih.gov/pubmed/25088546
http://dx.doi.org/10.1038/ncomms5521
Descripción
Sumario:The major facilitator superfamily (MFS) is the largest collection of structurally related membrane proteins that transport a wide array of substrates. The proton-coupled sugar transporter XylE is the first member of the MFS that has been structurally characterized in multiple transporting conformations, including both the outward and inward-facing states. Here we report the crystal structure of XylE in a new inward-facing open conformation, allowing us to visualize the rocker-switch movement of the N-domain against the C-domain during the transport cycle. Using molecular dynamics simulation, and functional transport assays, we describe the movement of XylE that facilitates sugar translocation across a lipid membrane and identify the likely candidate proton-coupling residues as the conserved Asp27 and Arg133. This study addresses the structural basis for proton-coupled substrate transport and release mechanism for the sugar porter family of proteins.