title: Structure of a periplasmic glucose-binding protein from Thermotoga maritima.
abstract: ABC transport systems have been characterized in organisms ranging from bacteria to humans. In most bacterial systems, the periplasmic component is the primary determinant of specificity of the transport complex as a whole. Here, the X-ray crystal structure of a periplasmic glucose-binding protein (GBP) from Thermotoga maritima determined at 2.4 Å resolution is reported. The molecule consists of two similar α/β domains connected by a three-stranded hinge region. In the current structure, a ligand (β-D-glucose) is buried between the two domains, which have adopted a closed conformation. Details of the substrate-binding sites revealed features that determine substrate specificity. In toto, ten residues from both domains form eight hydrogen bonds to the bound sugar and four aromatic residues (two from each domain) stabilize the substrate through stacking interactions.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Kandavelu
authors.initials: K
authors.lastname: Palani
authors.forename: Desigan
authors.initials: D
authors.lastname: Kumaran
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Burley
authors.forename: Subramanyam
authors.initials: S
authors.lastname: Swaminathan
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D018360:Crystallography, X-Ray; D005947:Glucose / Q000378:metabolism*; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D033902:Periplasmic Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D016415:Sequence Alignment; D013379:Substrate Specificity; D020124:Thermotoga maritima / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D033902:Periplasmic Binding Proteins; D005947:Glucose