title: Structure of the Thermus thermophilus putative periplasmic glutamate/glutamine-binding protein.
abstract: As part of a structural genomics project, the crystal structure of a 314-amino-acid protein encoded by Thermus thermophilus HB8 gene TT1099 was solved to 1.75 A using the multiple-wavelength anomalous dispersion (MAD) method and a selenomethionine-incorporated protein. The native protein structure was solved to 1.5 A using the molecular-replacement method. Both structures revealed a bound ligand, L-glutamate or L-glutamine, and a fold related to the periplasmic substrate-binding proteins (PSBP). Further comparative structural analysis with other PSBP-fold proteins revealed the conservation of the predicted membrane permease binding surface area and indicated that the T. thermophilus HB8 molecule is most likely to be an L-glutamate and/or an L-glutamine-binding protein related to the cluster 3 periplasmic receptors. However, the geometry of ligand binding is unique to the T. thermophilus HB8 molecule.
authors.affiliation: Highthroughput Factory, RIKEN Harima Institute, 1-1-1 Kouto, Mikazuki-cho, Sayo-gun, Hyogo 679-5148, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Takahashi
authors.forename: Eiji
authors.initials: E
authors.lastname: Inagaki
authors.forename: Chizu
authors.initials: C
authors.lastname: Kuroishi
authors.forename: Tahir H
authors.initials: TH
authors.lastname: Tahirov
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D004583:Electrons; D005971:Glutamates / Q000737:chemistry*; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012645:Selenomethionine / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D016963:Thermus thermophilus / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D005971:Glutamates; D008024:Ligands; C037853:glutamine transport proteins; D012645:Selenomethionine