Ins and outs of major facilitator superfamily antiporters.
The major facilitator superfamily (MFS) represents the largest group of secondary active membrane transporters, and its members transport a diverse range of substrates. Recent work shows that MFS antiporters, and perhaps all members of the MFS, share the same three-dimensional structure, consisting of two domains that surround a substrate translocation pore. The advent of crystal structures of three MFS antiporters sheds light on their fundamental mechanism; they operate via a single binding site, alternating-access mechanism that involves a rocker-switch type movement of the two halves of the protein. In the sn-glycerol-3-phosphate transporter (GlpT) from Escherichia coli, the substrate-binding site is formed by several charged residues and a histidine that can be protonated. Salt-bridge formation and breakage are involved in the conformational changes of the protein during transport. In this review, we attempt to give an account of a set of mechanistic principles that characterize all MFS antiporters.
Law
Christopher J
CJ
The Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA. law@saturn.med.nyu.edu
Maloney
Peter C
PC
Wang
Da-Neng
DN
D017920:Antiporters / Q000737:chemistry* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D029968:Escherichia coli Proteins; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation
D017920:Antiporters; D001426:Bacterial Proteins; C510268:EmrD protein, E coli; D029968:Escherichia coli Proteins; C488962:GlpT protein, E coli; D026901:Membrane Transport Proteins; C099549:OxlT protein, bacteria