The structural basis of substrate translocation by the Escherichia coli glycerol-3-phosphate transporter: a member of the major facilitator superfamily.
The major facilitator superfamily represents the largest group of secondary active membrane transporters in the cell. The 3.3A resolution structure of a member of this protein superfamily, the glycerol-3-phosphate transporter from the Escherichia coli inner membrane, reveals two domains connected by a long central loop. These N- and C-terminal domains, each containing a six-helix bundle, are related by pseudo-twofold symmetry. A substrate translocation pore is located between the two domains and is open to the cytoplasm. Two arginines at the closed end of the pore comprise the substrate-binding site. Biochemical experiments show that, upon substrate binding, the protein adopts a more compact conformation. The crystal structure suggests that the transporter operates through a single binding site, alternating access mechanism via a rocker-switch type of movement of the N- and C-terminal domains. The structure and mechanism of the glycerol-3-phosphate transporter form a paradigm for other members of the major facilitator superfamily.
Lemieux
M Joanne
MJ
Skirball Institute of Biomolecular Medicine and Department of Cell Biology, New York University School of Medicine, 540 First Avenue, New York, New York 10016, USA.
Huang
Yafei
Y
Wang
Da-Neng
DN
D001665:Binding Sites; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D009004:Monosaccharide Transport Proteins / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D013329:Structure-Activity Relationship
D029968:Escherichia coli Proteins; C488962:GlpT protein, E coli; D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; C063498:UhpT protein, E coli