2VRK

Structure of a seleno-methionyl derivative of wild type arabinofuranosidase from Thermobacillus xylanilyticus

2VRK の概要

• エントリーDOI: 10.2210/pdb2vrk/pdb
• 関連するPDBエントリー: 2VRQ
• 分子名称: ALPHA-L-ARABINOFURANOSIDASE, PHOSPHATE ION (3 entities in total)
• 機能のキーワード: hydrolase, glycosidase
• 由来する生物種: THERMOBACILLUS XYLANILYTICUS
• タンパク質・核酸の鎖数: 3
• 化学式量合計: 171183.76

構造登録者

Paes, G.,Skov, L.K.,ODonohue, M.J.,Remond, C.,Kastrup, J.S.,Gajhede, M.,Mirza, O. (登録日: 2008-04-09, 公開日: 2008-07-01, 最終更新日: 2024-11-06)

主引用文献

Paes, G.,Skov, L.K.,O'Donohue, M.J.,Remond, C.,Kastrup, J.S.,Gajhede, M.,Mirza, O.
The Structure of the Complex between a Branched Pentasaccharide and Thermobacillus Xylanilyticus Gh-51 Arabinofuranosidase Reveals Xylan-Binding Determinants and Induced Fit.
Biochemistry, 47:7441-, 2008

PubMed Abstract: The crystal structure of the family GH-51 alpha- l-arabinofuranosidase from Thermobacillus xylanilyticus has been solved as a seleno-methionyl derivative. In addition, the structure of an inactive mutant Glu176Gln is presented in complex with a branched pentasaccharide, a fragment of its natural substrate xylan. The overall structure shows the two characteristic GH-51 domains: a catalytic domain that is folded into a (beta/alpha) 8-barrel and a C-terminal domain that displays jelly roll architecture. The pentasaccharide is bound in a groove on the surface of the enzyme, with the mono arabinosyl branch entering a tight pocket harboring the catalytic dyad. Detailed analyses of both structures and comparisons with the two previously determined structures from Geobacillus stearothermophilus and Clostridium thermocellum reveal important details unique to the Thermobacillus xylanilyticus enzyme. In the absence of substrate, the enzyme adopts an open conformation. In the substrate-bound form, the long loop connecting beta-strand 2 to alpha-helix 2 closes the active site and interacts with the substrate through residues His98 and Trp99. The results of kinetic and fluorescence titration studies using mutants underline the importance of this loop, and support the notion of an interaction between Trp99 and the bound substrate. We suggest that the changes in loop conformation are an integral part of the T. xylanilyticus alpha- l-arabinofuranosidase reaction mechanism, and ensure efficient binding and release of substrate.

PubMed: 18563919
DOI: 10.1021/BI800424E

実験手法

X-RAY DIFFRACTION (2.2 Å)