Structure and Mechanism of the Glycerol-3-Phosphate Transporter from Escherichia coli

• Published in: Science (American Association for the Advancement of Science) Vol. 301; no. 5633; pp. 616 - 620
• Main Authors: Huang, Yafei, Lemieux, M. Joanne, Song, Jinmei, Auer, Manfred, Wang, Da-Neng
• Format: Journal Article
• Language: English
• Published: Washington, DC American Association for the Advancement of Science 01.08.2003; The American Association for the Advancement of Science
• Subjects: Amino Acid Sequence; Amino acids; Binding Sites; Biochemistry; Biological and medical sciences; Biological Transport; Cell Membrane - chemistry; Chemical bonds; Crystalline structure; Crystallization; Crystallography; Crystallography, X-Ray; Cytosol; Developmental Delays; Escherichia coli - chemistry; Escherichia coli - enzymology; Escherichia coli Proteins - chemistry; Escherichia coli Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Glycerophosphates - metabolism; Helix-Turn-Helix Motifs; Mass Spectrometry; Maya (People); Membrane transport proteins; Membrane Transport Proteins - chemistry; Membrane Transport Proteins - metabolism; Models, Molecular; Molecular biophysics; Molecular Sequence Data; Molecules; Mutation; P branes; Periplasm; Periplasm - metabolism; Phosphates; Phosphates - metabolism; Protein Conformation; Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary; Proteins; Scientific Concepts; String theory; Structure in molecular biology; Topology; Three dimensional structure; Membrane transport; Escherichia coli; Bacteria; Mechanism of action; Enterobacteriaceae; Crystalline structure
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1087619

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.