title: Energy coupling mechanisms of MFS transporters.
abstract: Major facilitator superfamily (MFS) is a large class of secondary active transporters widely expressed across all life kingdoms. Although a common 12-transmembrane helix-bundle architecture is found in most MFS crystal structures available, a common mechanism of energy coupling remains to be elucidated. Here, we discuss several models for energy-coupling in the transport process of the transporters, largely based on currently available structures and the results of their biochemical analyses. Special attention is paid to the interaction between protonation and the negative-inside membrane potential. Also, functional roles of the conserved sequence motifs are discussed in the context of the 3D structures. We anticipate that in the near future, a unified picture of the functions of MFS transporters will emerge from the insights gained from studies of the common architectures and conserved motifs.
authors.affiliation: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101.
authors.forename: Xuejun C
authors.initials: XC
authors.lastname: Zhang
authors.affiliation: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101.
authors.forename: Jie
authors.initials: J
authors.lastname: Heng
authors.affiliation: National Laboratory of Macromolecules, National Center of Protein Science-Beijing, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China, 100101.
authors.forename: Daohua
authors.initials: D
authors.lastname: Jiang
mesh_terms: D001665:Binding Sites; D001692:Biological Transport; D018360:Crystallography, X-Ray; D004734:Energy Metabolism / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism*; D008954:Models, Biological; D011487:Protein Conformation
chemical_list: D026901:Membrane Transport Proteins
keywords: MFS transporters; energy coupling mechanisms; membrane potential; motif A