2VQ4

Carbohydrate-binding of the starch binding domain of Rhizopus oryzae glucoamylase in complex with beta-cyclodextrin and maltoheptaose

2VQ4 の概要

• エントリーDOI: 10.2210/pdb2vq4/pdb
• 関連するPDBエントリー: 2V8L 2V8M
• 分子名称: GLUCOAMYLASE A (2 entities in total)
• 機能のキーワード: rhizopus oryzae glucoamylase, hydrolase, carbohydrate binding, starch binding domain
• 由来する生物種: RHIZOPUS ORYZAE
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 11662.58

構造登録者

Tung, J.-Y.,Liu, Y.-Y.,Sun, Y.-J. (登録日: 2008-03-11, 公開日: 2009-07-07, 最終更新日: 2023-12-13)

主引用文献

Tung, J.-Y.,Chang, M.D.,Chou, W.,Liu, Y.-Y.,Yeh, Y.,Chang, F.,Lin, S.,Qiu, Z.,Sun, Y.-J.
Crystal Structures of the Starch-Binding Domain from Rhizopus Oryzae Glucoamylase Reveal a Polysaccharide-Binding Path.
Biochem.J., 416:27-, 2008

PubMed Abstract: GA (glucoamylase) hydrolyses starch and polysaccharides to beta-D-glucose. RoGA (Rhizopus oryzae GA) consists of two functional domains, an N-terminal SBD (starch-binding domain) and a C-terminal catalytic domain, which are connected by an O-glycosylated linker. In the present study, the crystal structures of the SBD from RoGA (RoGACBM21) and the complexes with beta-cyclodextrin (SBD-betaCD) and maltoheptaose (SBD-G7) were determined. Two carbohydrate binding sites, I (Trp(47)) and II (Tyr(32)), were resolved and their binding was co-operative. Besides the hydrophobic interaction, two unique polyN loops comprising consecutive asparagine residues also participate in the sugar binding. A conformational change in Tyr(32) was observed between unliganded and liganded SBDs. To elucidate the mechanism of polysaccharide binding, a number of mutants were constructed and characterized by a quantitative binding isotherm and Scatchard analysis. A possible binding path for long-chain polysaccharides in RoGACBM21 was proposed.

PubMed: 18588504
DOI: 10.1042/BJ20080580

実験手法

X-RAY DIFFRACTION (1.25 Å)