1G9H

TERNARY COMPLEX BETWEEN PSYCHROPHILIC ALPHA-AMYLASE, COMII (PSEUDO TRI-SACCHARIDE FROM BAYER) AND TRIS (2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL)

1G9H の概要

• エントリーDOI: 10.2210/pdb1g9h/pdb
• 関連するPDBエントリー: 1AQH 1AQM 1B0I 1G94
• 分子名称: ALPHA-AMYLASE, 4,6-dideoxy-4-{[(1S,5R,6S)-3-formyl-5,6-dihydroxy-4-oxocyclohex-2-en-1-yl]amino}-alpha-D-xylo-hex-5-enopyranose-(1-4)-beta-D-glucopyranose, CALCIUM ION, ... (6 entities in total)
• 機能のキーワード: alpha-beta 8 barrel, 3 domain structure, hydrolase
• 由来する生物種: Pseudoalteromonas haloplanktis
• 細胞内の位置: Secreted : P29957
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 49622.52

構造登録者

Aghajari, N.,Roth, M.,Haser, R. (登録日: 2000-11-23, 公開日: 2002-06-26, 最終更新日: 2024-11-20)

主引用文献

AGHAJARI, N.,ROTH, M.,HASER, R.
Crystallographic evidence of a transglycosylation reaction: ternary complexes of a psychrophilic alpha-amylase.
Biochemistry, 41:4273-4280, 2002

PubMed Abstract: The psychrophilic Pseudoalteromonas haloplanctis alpha-amylase is shown to form ternary complexes with two alpha-amylase inhibitors present in the active site region, namely, a molecule of Tris and a trisaccharide inhibitor or heptasaccharide inhibitor, respectively. The crystal structures of these complexes have been determined by X-ray crystallography to 1.80 and 1.74 A resolution, respectively. In both cases, the prebound inhibitor Tris is expelled from the active site by the incoming oligosaccharide inhibitor substrate analogue, but stays linked to it, forming well-defined ternary complexes with the enzyme. These results illustrate competition in the crystalline state between two inhibitors, an oligosaccharide substrate analogue and a Tris molecule, bound at the same time in the active site region. Taken together, these structures show that the enzyme performs transglycosylation in the complex with the pseudotetrasaccharide acarbose (confirmed by a mutant structure), leading to a well-defined heptasaccharide, considered as a more potent inhibitor. Furthermore, the substrate-induced ordering of water molecules within a channel highlights a possible pathway used for hydrolysis of starch and related poly- and oligosaccharides.

PubMed: 11914073
DOI: 10.1021/bi0160516

実験手法

X-RAY DIFFRACTION (1.8 Å)