2BVW

CELLOBIOHYDROLASE II (CEL6A) FROM HUMICOLA INSOLENS IN COMPLEX WITH GLUCOSE AND CELLOTETRAOSE

2BVW の概要

• エントリーDOI: 10.2210/pdb2bvw/pdb
• 関連するBIRD辞書のPRD_ID: PRD_900011 PRD_900014
• 分子名称: CELLOBIOHYDROLASE II, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-beta-D-glucopyranose, beta-D-glucopyranose-(1-4)-beta-D-glucopyranose-(1-4)-alpha-D-glucopyranose, ... (7 entities in total)
• 機能のキーワード: hydrolase, cellulose degradation, cellobiohydrolase, cellulase, glycoside hydrolase family 6
• 由来する生物種: Humicola insolens
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 82647.43

構造登録者

Varrot, A.,Davies, G.J.,Schulein, M. (登録日: 1999-02-18, 公開日: 2000-02-25, 最終更新日: 2023-08-23)

主引用文献

Varrot, A.,Schulein, M.,Davies, G.J.
Structural changes of the active site tunnel of Humicola insolens cellobiohydrolase, Cel6A, upon oligosaccharide binding.
Biochemistry, 38:8884-8891, 1999

PubMed Abstract: The mechanisms of crystalline cellulose degradation by cellulases are of paramount importance for the exploitation of these enzymes in applied processes, such as biomass conversion. Cellulases have traditionally been classified into cellobiohydrolases, which are effective in the degradation of crystalline materials, and endoglucanases, which appear to act on "soluble" regions of the substrate. Humicola insolensCel6A (CBH II) is a cellobiohydrolase from glycoside hydrolase family 6 whose native structure has been determined at 1.9 A resolution [Varrot, A., Hastrup, S., Schülein, M., and Davies, G. J. (1999) Biochem. J. 337, 297-304]. Here we present the structure of the catalytic core domain of Humicola insolens cellobiohydrolase II Cel6A in complex with glucose/cellotetraose at 1.7 A resolution. Crystals of Cel6A, grown in the presence of cellobiose, reveal six binding subsites, with a single glucose moiety bound in the -2 subsite and cellotetraose in the +1 to +4 subsites. The complex structure is strongly supportive of the assignment of Asp 226 as the catalytic acid and consistent with proposals that Asp 405 acts as the catalytic base. The structure undergoes several conformational changes upon substrate binding, the most significant of which is a closing of the two active site loops (residues 174-196 and 397-435) with main-chain movements of up to 4.5 A observed. This complex not only defines the polysaccharide-enzyme interactions but also provides the first three-dimensional demonstration of conformational change in this class of enzymes.

PubMed: 10413461
DOI: 10.1021/bi9903998

実験手法

X-RAY DIFFRACTION (1.7 Å)