Structure and mechanism of the glycerol-3-phosphate transporter from Escherichia coli.
The major facilitator superfamily represents the largest group of secondary membrane transporters in the cell. Here we report the 3.3 angstrom resolution structure of a member of this superfamily, GlpT, which transports glycerol-3-phosphate into the cytoplasm and inorganic phosphate into the periplasm. The amino- and carboxyl-terminal halves of the protein exhibit a pseudo two-fold symmetry. Closed off to the periplasm, a centrally located substrate-translocation pore contains two arginines at its closed end, which comprise the substrate-binding site. Upon substrate binding, the protein adopts a more compact conformation. We propose that GlpT operates by a single-binding site, alternating-access mechanism through a rocker-switch type of movement.
Huang
Yafei
Y
Skirball Institute of Biomolecular Medicine and Department of Cell Biology, New York University School of Medicine, 540 First Avenue, New York, NY 10016, USA.
Lemieux
M Joanne
MJ
Song
Jinmei
J
Auer
Manfred
M
Wang
Da-Neng
DN
D000595:Amino Acid Sequence; D001665:Binding Sites; D001692:Biological Transport; D002462:Cell Membrane / Q000737:chemistry; D003460:Crystallization; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000737:chemistry* / Q000201:enzymology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism*; D019077:Helix-Turn-Helix Motifs; D013058:Mass Spectrometry; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019897:Periplasm / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D029968:Escherichia coli Proteins; C488962:GlpT protein, E coli; D005994:Glycerophosphates; D026901:Membrane Transport Proteins; D010710:Phosphates; C029620:alpha-glycerophosphoric acid