Glycerol-3-phosphate transporter of Escherichia coli: structure, function and regulation.
Glycerol-3-phosphate (G3P) plays a major role in glycolysis and phospholipid biosynthesis in the cell. Escherichia coli uses a secondary membrane transporter protein, GlpT, to uptake G3P into the cytoplasm. The crystal structure of the protein was recently determined to 3.3 A resolution. The protein consists of an N- and a C-terminal domain, each formed by a compact bundle of six transmembrane alpha-helices. The substrate-translocation pore is found at the domain interface and faces the cytoplasm. At the closed end of the pore is the substrate binding site, which is formed by two arginine residues. In combination with biochemical data, the crystal structure suggests a single binding site, alternating access mechanism for substrate translocation, namely, the substrate bound at the N- and C-terminal domain interface is transported across the membrane via a rocker-switch type of movement of the domains. Furthermore, GlpT may serve as a structural and mechanistic paradigm for other secondary active membrane transporters.
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, NY 10016, USA.
Huang
Yafei
Y
Wang
Da-Neng
DN
D001692:Biological Transport; D004926:Escherichia coli / Q000737:chemistry / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D026901:Membrane Transport Proteins / Q000737:chemistry* / Q000378:metabolism
D029968:Escherichia coli Proteins; C488962:GlpT protein, E coli; D026901:Membrane Transport Proteins