2VZO

Crystal structure of Amycolatopsis orientalis exo-chitosanase CsxA

2VZO の概要

• エントリーDOI: 10.2210/pdb2vzo/pdb
• 関連するPDBエントリー: 2VZP 2VZQ 2VZR 2VZS 2VZT 2VZU 2VZV
• 分子名称: EXO-BETA-D-GLUCOSAMINIDASE, CADMIUM ION, ACETATE ION, ... (5 entities in total)
• 機能のキーワード: gh2, csxa, pnp-glucosamine, glycoside hydrolase, exo-beta-d-glucosaminidase, hydrolase
• 由来する生物種: AMYCOLATOPSIS ORIENTALIS
• 細胞内の位置: Secreted, extracellular space: Q56F26
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 223151.37

構造登録者

Lammerts van Bueren, A.,Ghinet, M.G.,Gregg, K.,Fleury, A.,Brzezinski, R.,Boraston, A.B. (登録日: 2008-08-05, 公開日: 2008-10-14, 最終更新日: 2024-11-20)

主引用文献

Lammerts Van Bueren, A.,Ghinet, M.G.,Gregg, K.,Fleury, A.,Brzezinski, R.,Boraston, A.B.
The Structural Basis of Substrate Recognition in an Exo-Beta-D-Glucosaminidase Involved in Chitosan Hydrolysis.
J.Mol.Biol., 385:131-, 2009

PubMed Abstract: Family 2 of the glycoside hydrolase classification is one of the largest families. Structurally characterized members of this family include enzymes with beta-galactosidase activity (Escherichia coli LacZ), beta-glucuronidase activity (Homo sapiens GusB), and beta-mannosidase activity (Bacteroides thetaiotaomicron BtMan2A). Here, we describe the structure of a family 2 glycoside hydrolase, CsxA, from Amycolatopsis orientalis that has exo-beta-D-glucosaminidase (exo-chitosanase) activity. Analysis of a product complex (1.85 A resolution) reveals a unique negatively charged pocket that specifically accommodates the nitrogen of nonreducing end glucosamine residues, allowing this enzyme to discriminate between glucose and glucosamine. This also provides structural evidence for the role of E541 as the catalytic nucleophile and D469 as the catalytic acid/base. The structures of an E541A mutant in complex with a natural beta-1,4-D-glucosamine tetrasaccharide substrate and both E541A and D469A mutants in complex with a pNP-beta-D-glucosaminide synthetic substrate provide insight into interactions in the +1 subsite of this enzyme. Overall, a comparison with the active sites of other GH2 enzymes highlights the unique architecture of the CsxA active site, which imparts specificity for its cationic substrate.

PubMed: 18976664
DOI: 10.1016/J.JMB.2008.10.031

実験手法

X-RAY DIFFRACTION (2.24 Å)