1FQC

CRYSTAL STRUCTURE OF MALTOTRIOTOL BOUND TO CLOSED-FORM MALTODEXTRIN BINDING PROTEIN

1FQC の概要

• エントリーDOI: 10.2210/pdb1fqc/pdb
• 関連するPDBエントリー: 1ANF 1OMP
• 分子名称: MALTODEXTRIN-BINDING PROTEIN, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-D-glucose (3 entities in total)
• 機能のキーワード: sugar-binding protein, maltotriotol, sugar binding protein
• 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: 41199.49

構造登録者

Duan, X.,Hall, J.A.,Nikaido, H.,Quiocho, F.A. (登録日: 2000-09-04, 公開日: 2001-03-14, 最終更新日: 2024-02-07)

主引用文献

Duan, X.,Hall, J.A.,Nikaido, H.,Quiocho, F.A.
Crystal structures of the maltodextrin/maltose-binding protein complexed with reduced oligosaccharides: flexibility of tertiary structure and ligand binding.
J.Mol.Biol., 306:1115-1126, 2001

PubMed Abstract: The structure of the maltodextrin or maltose-binding protein, an initial receptor for bacterial ABC-type active transport and chemotaxis, consists of two globular domains that are separated by a groove wherein the ligand is bound and enclosed by an inter-domain rotation. Here, we report the determination of the crystal structures of the protein complexed with reduced maltooligosaccharides (maltotriitol and maltotetraitol) in both the "closed" and "open" forms. Although these modified sugars bind to the receptor, they are not transported by the wild-type transporter. In the closed structures, the reduced sugars are buried in the groove and bound by both domains, one domain mainly by hydrogen-bonding interactions and the other domain primarily by non-polar interactions with aromatic side-chains. In the open structures, which abrogate both cellular activities of active transport and chemotaxis because of the large separation between the two domains, the sugars are bound almost exclusively to the domain rich in aromatic residues. The binding site for the open chain glucitol residue extends to a subsite that is distinct from those for the glucose residues that were uncovered in prior structural studies of the binding of active linear maltooligosaccharides. Occupation of this subsite may also account for the inability of the reduced oligosaccharides to be transported. The structures reported here, combined with those previously determined for several other complexes with active oligosaccharides in the closed form and with cyclodextrin in the open form, revealed at least four distinct modes of ligand binding but with only one being functionally active. This versatility reflects the flexibility of the protein, from very large motions of interdomain rotation to more localized side-chain conformational changes, and adaptation by the oligosaccharides as well.

PubMed: 11237621
DOI: 10.1006/jmbi.2001.4456

実験手法

X-RAY DIFFRACTION (2.3 Å)