6abp | pdb_00006abp

SUGAR-BINDING AND CRYSTALLOGRAPHIC STUDIES OF AN ARABINOSE-BINDING PROTEIN MUTANT (MET108LEU) WHICH EXHIBITS ENHANCED AFFINITY AND ALTERED SPECIFICITY

spinqualitylabelsall models 6abp, resolution 1.67Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6abp is a 1 chain structure with sequence from "bacillus_coli"_migula_1895 "bacillus coli" migula 1895. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ARA, ARB Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [ARAF_ECOLI] Involved in the high-affinity L-arabinose membrane transport system. Binds with high affinity to arabinose, but can also bind D-galactose (approximately 2-fold reduction) and D-fucose (approximately 40-fold reduction). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed In addition to hydrogen bonds, van der Waals forces contribute to the affinity of protein-carbohydrate interactions. Nonpolar van der Waals contacts in the complexes of the L-arabinose-binding protein (ABP) with monosaccharides have been studied by means of site-directed mutagenesis, equilibrium and rapid kinetic binding techniques, and X-ray crystallography. ABP, a periplasmic transport receptor of Escherichia coli, binds L-arabinose, D-galactose, and D-fucose with preferential affinity in the order of Ara greater than Gal much greater than Fuc. Well-refined, high-resolution structures of ABP complexed with the three sugars revealed that the structural differences in the ABP-sugar complexes are localized around C5 of the sugars, where the equatorial H of Ara has been substituted for CH3 (Fuc) or CH2OH (Gal). The side chain of Met108 undergoes a sterically dictated, ligand-specific, conformational change to optimize nonpolar interactions between its methyl group and the sugar. We found that the Met108Leu ABP binds Gal tighter than wild-type ABP binds Ara and exhibits a preference for ligand in the order of Gal much greater than Fuc greater than Ara. The differences in affinity can be attributed to differences in the dissociation rates of the ABP-sugar complexes. We have refined at better than 1.7-A resolution the crystal structures of the Met108Leu ABP complexed with each of the sugars and offer a molecular explanation for the altered binding properties. Sugar-binding and crystallographic studies of an arabinose-binding protein mutant (Met108Leu) that exhibits enhanced affinity and altered specificity.,Vermersch PS, Lemon DD, Tesmer JJ, Quiocho FA Biochemistry. 1991 Jul 16;30(28):6861-6. PMID:2069949 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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