1gcg
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| , resolution 1.9Å | |||||||
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| Ligands: | |||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
THE 1.9 ANGSTROMS X-RAY STRUCTURE OF A CLOSED UNLIGANDED FORM OF THE PERIPLASMIC GLUCOSE(SLASH)GALACTOSE RECEPTOR FROM SALMONELLA TYPHIMURIUM
OverviewOverview
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.
About this StructureAbout this Structure
1GCG is a Single protein structure of sequence from Salmonella typhimurium. Full crystallographic information is available from OCA.
ReferenceReference
The 1.9 A x-ray structure of a closed unliganded form of the periplasmic glucose/galactose receptor from Salmonella typhimurium., Flocco MM, Mowbray SL, J Biol Chem. 1994 Mar 25;269(12):8931-6. PMID:8132630
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