1GGG

GLUTAMINE BINDING PROTEIN OPEN LIGAND-FREE STRUCTURE

Summary for 1GGG

• Entry DOI: 10.2210/pdb1ggg/pdb
• Descriptor: GLUTAMINE BINDING PROTEIN (2 entities in total)
• Functional Keywords: amino-acid transport, glnbp, open form, binding protein
• Biological source: Escherichia coli
• Total number of polymer chains: 2
• Total formula weight: 49960.72

Authors

Hsiao, C.-D.,Sun, Y.-J.,Rose, J.,Wang, B.-C. (deposition date: 1996-06-25, release date: 1996-11-08, Last modification date: 2024-02-07)

Primary citation

Hsiao, C.D.,Sun, Y.J.,Rose, J.,Wang, B.C.
The crystal structure of glutamine-binding protein from Escherichia coli.
J.Mol.Biol., 262:225-242, 1996

PubMed Abstract: The crystal structure of the glutamine-binding protein (GlnBP) from Escherichia coli in a ligand-free "open" conformational state has been determined by isomorphous replacement methods and refined to an R-value of 21.4% at 2.3 A resolution. There are two molecules in the asymmetric unit, related by pseudo 4-fold screw symmetry. The refined model consists of 3587 non-hydrogen atoms from 440 residues (two monomers), and 159 water molecules. The structure has root-mean-square deviations of 0.013 A from "ideal" bond lengths and 1.5 degrees from "ideal" bond angles. The GlnBP molecule has overall dimensions of approximately 60 A x 40 A x 35 A and is made up of two domains (termed large and small), which exhibit a similar supersecondary structure, linked by two antiparallel beta-strands. The small domain contains three alpha-helices and four parallel and one antiparallel beta-strands. The large domain is similar to the small domain but contains two additional alpha-helices and three more short antiparallel beta-strands. A comparison of the secondary structural motifs of GlnBP with those of other periplasmic binding proteins is discussed. A model of the "closed form" GlnBP-Gln complex has been proposed based on the crystal structures of the histidine-binding protein-His complex and "open form" GlnBP. This model has been successfully used as a search model in the crystal structure determination of the "closed form" GlnBP-Gln complex by molecular replacement methods. The model agrees remarkably well with the crystal structure of the Gln-GlnBP complex with root-mean-square deviation of 1.29 A. Our study shows that, at least in our case, it is possible to predict one conformational state of a periplasmic binding protein from another conformational state of the protein. The glutamine-binding pockets of the model and the crystal structure are compared and the modeling technique is described.

PubMed: 8831790
DOI: 10.1006/jmbi.1996.0509

Experimental method

X-RAY DIFFRACTION (2.3 Å)