3WEN

Sugar beet alpha-glucosidase with acarviosyl-maltopentaose

3WEN の概要

• エントリーDOI: 10.2210/pdb3wen/pdb
• 関連するPDBエントリー: 3W37 3W38 3WEL 3WEM 3WEO
• 分子名称: Alpha-glucosidase, alpha-L-fucopyranose-(1-3)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)]2-acetamido-2-deoxy-beta-D-glucopyranose, 4,6-dideoxy-4-{[(1S,4R,5S,6S)-4,5,6-trihydroxy-3-(hydroxymethyl)cyclohex-2-en-1-yl]amino}-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, ... (6 entities in total)
• 機能のキーワード: alpha-glucosidase, glycoside hydrolase family 31, (beta/alpha)8-barrel, acarbose derivative, hydrolase
• 由来する生物種: Beta vulgaris (Sugar beet)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 104753.26

構造登録者

Tagami, T.,Yamashita, K.,Okuyama, M.,Mori, H.,Yao, M.,Kimura, A. (登録日: 2013-07-09, 公開日: 2014-07-16, 最終更新日: 2023-11-08)

主引用文献

Tagami, T.,Yamashita, K.,Okuyama, M.,Mori, H.,Yao, M.,Kimura, A.
Structural advantage of sugar beet alpha-glucosidase to stabilize the Michaelis complex with long-chain substrate
J.Biol.Chem., 290:1796-1803, 2014

PubMed Abstract: The α-glucosidase from sugar beet (SBG) is an exo-type glycosidase. The enzyme has a pocket-shaped active site, but efficiently hydrolyzes longer maltooligosaccharides and soluble starch due to lower Km and higher kcat/Km for such substrates. To obtain structural insights into the mechanism governing its unique substrate specificity, a series of acarviosyl-maltooligosaccharides was employed for steady-state kinetic and structural analyses. The acarviosyl-maltooligosaccharides have a longer maltooligosaccharide moiety compared with the maltose moiety of acarbose, which is known to be the transition state analog of α-glycosidases. The clear correlation obtained between log Ki of the acarviosyl-maltooligosaccharides and log(Km/kcat) for hydrolysis of maltooligosaccharides suggests that the acarviosyl-maltooligosaccharides are transition state mimics. The crystal structure of the enzyme bound with acarviosyl-maltohexaose reveals that substrate binding at a distance from the active site is maintained largely by van der Waals interactions, with the four glucose residues at the reducing terminus of acarviosyl-maltohexaose retaining a left-handed single-helical conformation, as also observed in cycloamyloses and single helical V-amyloses. The kinetic behavior and structural features suggest that the subsite structure suitable for the stable conformation of amylose lowers the Km for long-chain substrates, which in turn is responsible for higher specificity of the longer substrates.

PubMed: 25451917
DOI: 10.1074/jbc.M114.606939

実験手法

X-RAY DIFFRACTION (2.59 Å)