7ABP

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

7ABP の概要

• エントリーDOI: 10.2210/pdb7abp/pdb
• 分子名称: L-ARABINOSE-BINDING PROTEIN, alpha-D-fucopyranose, beta-D-fucopyranose, ... (4 entities in total)
• 機能のキーワード: binding proteins
• 由来する生物種: Escherichia coli
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 33561.27

構造登録者

Vermersch, P.S.,Tesmer, J.J.G.,Quiocho, F.A. (登録日: 1991-04-25, 公開日: 1991-10-15, 最終更新日: 2024-03-06)

主引用文献

Vermersch, P.S.,Lemon, D.D.,Tesmer, J.J.,Quiocho, F.A.
Sugar-binding and crystallographic studies of an arabinose-binding protein mutant (Met108Leu) that exhibits enhanced affinity and altered specificity.
Biochemistry, 30:6861-6866, 1991

PubMed Abstract: 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.

PubMed: 2069949
DOI: 10.1021/bi00242a009

実験手法

X-RAY DIFFRACTION (1.67 Å)