The 1.9 A x-ray structure of a closed unliganded form of the periplasmic glucose/galactose receptor from Salmonella typhimurium.Flocco, M.M., Mowbray, S.L.
(1994) J.Biol.Chem. 269: 8931-8936
- PubMed: 8132630
- PubMed Abstract:
- The 1.7 Angstroms Refined X-Ray Structure of the Periplasmic Glucose(Slash)Galactose Receptor from Salmonella Typhimurium
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(1993) J.Mol.Biol. 233: 739
- Structure of the Periplasmic Glucose(Slash)Galactose Receptor of Salmonella Typhimurium
Mowbray, S.L.,Smith, R.D.,Cole, L.B.
(1990) Receptor 1: 41
- Preliminary X-Ray Data for the Galactose Binding Protein from Salmonella Typhimurium
Alber, T.,Fahnestock, M.,Mowbray, S.L.,Petsko, G.A.
(1981) J.Mol.Biol. 147: 471
- Ribose and Glucose-Galactose Receptors Competitors in Bacterial Chemotaxis
(1992) J.Mol.Biol. 227: 418
The three-dimensional structure of a ligand-free closed form of the glucose/galactose binding protein from Salmonella typhimurium has been determined at a resolution of 1.9 A. The crystallographic R-factor for the refined structure is 17.9%. The mode ...
The three-dimensional structure of a ligand-free closed form of the glucose/galactose binding protein from Salmonella typhimurium has been determined at a resolution of 1.9 A. The crystallographic R-factor for the refined structure is 17.9%. The model contains all the atoms of the 309 residues of the protein sequence, a calcium ion, and 174 water molecules. The root mean square (r.m.s.) deviations for the whole molecule are: 0.010 A for bond lengths and 2.44 degrees for bond angles, indicating a good stereochemistry for the model. This structure shows that the protein is able to close in the absence of ligand, adopting a conformation similar to the liganded form but slightly more open. Water molecules satisfy the hydrogen bonding ability of the hydrophilic side chains of the binding site in a manner which is reminiscent of the sugars' hydrogen-bonding patterns. Since packing forces are weak, the crystallization event is unlikely to trigger a change from an open to a closed conformation. Instead, the latter must be one of the species in equilibrium in solution which is selected by packing in the crystal lattice.
Department of Molecular Biology, Swedish University of Agricultural Sciences, Uppsala Biomedical Center.