2D2O

Structure of a complex of Thermoactinomyces vulgaris R-47 alpha-amylase 2 with maltohexaose demonstrates the important role of aromatic residues at the reducing end of the substrate binding cleft

2D2O の概要

• エントリーDOI: 10.2210/pdb2d2o/pdb
• 関連するPDBエントリー: 1VFK 1VFM 1VFO 1VFU
• 関連するBIRD辞書のPRD_ID: PRD_900035
• 分子名称: Neopullulanase 2, 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, CALCIUM ION, ... (4 entities in total)
• 機能のキーワード: beta/alpha barrel, hydrolase
• 由来する生物種: Thermoactinomyces vulgaris
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 137168.13

構造登録者

Ohtaki, A.,Mizuno, M.,Yoshida, H.,Tonozuka, T.,Sakano, Y.,Kamitori, S. (登録日: 2005-09-13, 公開日: 2006-08-29, 最終更新日: 2024-05-29)

主引用文献

Ohtaki, A.,Mizuno, M.,Yoshida, H.,Tonozuka, T.,Sakano, Y.,Kamitori, S.
Structure of a complex of Thermoactinomyces vulgaris R-47 alpha-amylase 2 with maltohexaose demonstrates the important role of aromatic residues at the reducing end of the substrate binding cleft
Carbohydr.Res., 341:1041-1046, 2006

PubMed Abstract: Thermoactinomyces vulgaris R-47 alpha-amylase 2 (TVAII) can efficiently hydrolyze both starch and cyclomaltooligosaccharides (cyclodextrins). The crystal structure of an inactive mutant TVAII in a complex with maltohexaose was determined at a resolution of 2.1A. TVAII adopts a dimeric structure to form two catalytic sites, where substrates are found to bind. At the catalytic site, there are many hydrogen bonds between the enzyme and substrate at the non-reducing end from the hydrolyzing site, but few hydrogen bonds at the reducing end, where two aromatic residues, Trp356 and Tyr45, make effective interactions with a substrate. Trp356 drastically changes its side-chain conformation to achieve a strong stacking interaction with the substrate, and Tyr45 from another molecule forms a water-mediated hydrogen bond with the substrate. Kinetic analysis of the wild-type and mutant enzymes in which Trp356 and/or Tyr45 were replaced with Ala suggested that Trp356 and Tyr45 are essential to the catalytic reaction of the enzyme, and that the formation of a dimeric structure is indispensable for TVAII to hydrolyze both starch and cyclodextrins.

PubMed: 16564038
DOI: 10.1016/j.carres.2006.01.029

実験手法

X-RAY DIFFRACTION (2.1 Å)