3WMS

The crystal structure of Y195I mutant alpha-cyclodextrin glycosyltransferase from Paenibacillus macerans

3WMS の概要

• エントリーDOI: 10.2210/pdb3wms/pdb
• 分子名称: Alpha-cyclodextrin glucanotransferase, CALCIUM ION (3 entities in total)
• 機能のキーワード: tim barrel, igg-like beta-barrel, cyclodextrin glycosyltransferase, transferase
• 由来する生物種: Paenibacillus macerans
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 78382.51

構造登録者

Xie, T.,Hou, Y.J.,Li, D.F.,Yue, Y.,Qian, S.J.,Chao, Y.P. (登録日: 2013-11-24, 公開日: 2014-11-12, 最終更新日: 2023-11-08)

主引用文献

Xie, T.,Hou, Y.J.,Li, D.F.,Yue, Y.,Qian, S.J.,Chao, Y.P.
Structural basis of a mutant Y195I alpha-cyclodextrin glycosyltransferase with switched product specificity from alpha-cyclodextrin to beta-/ gamma-cyclodextrin
J.Biotechnol., 182-183:92-96, 2014

PubMed Abstract: Cyclodextrin glycosyltransferase (EC 2.4.1.19) (CGTase) is an extracellular bacterial enzyme which has the unique capability of forming cyclodextrins from starch. Our previous investigation revealed that a mutant Y195I α-CGTase drastically altered the cyclodextrin specificity by switching toward the synthesis of both β- and γ-CDs (Xie et al., 2013a,b). In this study, we determined one X-ray structure of the mutant Y195I α-CGTase at 2.3Å. The overall structure was similar to that of the typical β-CGTase from Bacillus circulans 251, with minor difference in flexible domains since they showed about 70% homogeneity of amino acid sequences. The central site with isoleucine tended to be more flexible than tyrosine thus made the sugar chain, during the cyclization process, form a larger cyclodextrin like β- and γ-CDs surrounding the central site instead of α-CD. Superposition of the structure of Y195I α-CGTase with those of β-CGTase and γ-CGTase showed that residues Lys232, Lys89 and Arg177 at subsites +2, -3 and -7 could form smaller substrate binding cavity. In summary, the crystal structure revealed that moderate increase of mobility of the central site resulted in the switched product specificity from α-CD to β- and γ-CDs of the mutant Y195I α-CGTase. The space differences alongside the active domain may be another factor that impacts the product specificity of the CGTase.

PubMed: 24637377
DOI: 10.1016/j.jbiotec.2014.03.014

実験手法

X-RAY DIFFRACTION (2.3 Å)