2GH9

Thermus thermophilus maltotriose binding protein bound with maltotriose

2GH9 の概要

• エントリーDOI: 10.2210/pdb2gh9/pdb
• 関連するPDBエントリー: 2GHA 2GHB
• 関連するBIRD辞書のPRD_ID: PRD_900009
• 分子名称: maltose/maltodextrin-binding protein, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose (3 entities in total)
• 機能のキーワード: mbp, thermus thermophilus, maltose binding protein, thermophilic protein, periplasmic binding protein, sugar binding protein
• 由来する生物種: Thermus thermophilus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 42608.90

構造登録者

Cuneo, M.J.,Changela, A.,Beese, L.S.,Hellinga, H.W. (登録日: 2006-03-27, 公開日: 2007-02-06, 最終更新日: 2024-02-14)

主引用文献

Cuneo, M.J.,Changela, A.,Beese, L.S.,Hellinga, H.W.
Structural adaptations that modulate monosaccharide, disaccharide, and trisaccharide specificities in periplasmic maltose-binding proteins.
J.Mol.Biol., 389:157-166, 2009

PubMed Abstract: Periplasmic binding proteins comprise a superfamily that is present in archaea, prokaryotes, and eukaryotes. Periplasmic binding protein ligand-binding sites have diversified to bind a wide variety of ligands. Characterization of the structural mechanisms by which functional adaptation occurs is key to understanding the evolution of this important protein superfamily. Here we present the structure and ligand-binding properties of a maltotriose-binding protein identified from the Thermus thermophilus genome sequence. We found that this receptor has a high affinity for the trisaccharide maltotriose (K(d)<1 microM) but little affinity for disaccharides that are transported by a paralogous maltose transport operon present in T. thermophilus. Comparison of this structure to other proteins that adopt the maltose-binding protein fold but bind monosaccharides, disaccharides, or trisaccharides reveals the presence of four subsites that bind individual glucose ring units. Two loops and three helical segments encode adaptations that control the presence of each subsite by steric blocking or hydrogen bonding. We provide a model in which the energetics of long-range conformational equilibria controls subsite occupancy and ligand binding.

PubMed: 19361522
DOI: 10.1016/j.jmb.2009.04.008

実験手法

X-RAY DIFFRACTION (1.95 Å)