1CXI

WILD-TYPE CGTASE FROM BACILLUS CIRCULANS STRAIN 251 AT 120 K AND PH 7.55

1CXI の概要

• エントリーDOI: 10.2210/pdb1cxi/pdb
• 関連するBIRD辞書のPRD_ID: PRD_900001
• 分子名称: CYCLODEXTRIN GLYCOSYLTRANSFERASE, alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose, CALCIUM ION, ... (4 entities in total)
• 機能のキーワード: glycosyltransferase
• 由来する生物種: Bacillus circulans
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 75682.53

構造登録者

Knegtel, R.M.A.,Strokopytov, B.V.,Dijkstra, B.W. (登録日: 1995-07-31, 公開日: 1995-12-15, 最終更新日: 2024-11-13)

主引用文献

Knegtel, R.M.,Strokopytov, B.,Penninga, D.,Faber, O.G.,Rozeboom, H.J.,Kalk, K.H.,Dijkhuizen, L.,Dijkstra, B.W.
Crystallographic studies of the interaction of cyclodextrin glycosyltransferase from Bacillus circulans strain 251 with natural substrates and products.
J.Biol.Chem., 270:29256-29264, 1995

PubMed Abstract: Asp-229, Glu-257, and Asp-328 constitute the catalytic residues in cyclodextrin glycosyl transferase from Bacillus circulans strain 251. Via site-directed mutagenesis constructed D229N, E257Q, and D328N mutant proteins showed a 4,000-60,000-fold reduction of cyclization activity. A D229N/E257Q double mutant showed a 700,000-fold reduction and was crystallized for use in soaking experiments with alpha-cyclodextrin. Crystal structures were determined of wild type CGTase soaked at elevated pH with alpha-cyclodextrin (resolution, 2.1 A) and maltoheptaose (2.4 A). In addition, structures at cryogenic temperature were solved of the unliganded enzyme (2.2 A) and of the D229N/E257Q mutant after soaking with alpha-cyclodextrin (2.6 A). In the crystals soaked in alpha-cyclodextrin and maltoheptaose, a maltotetraose molecule is observed to bind in the active site. Residue 229 is at hydrogen bonding distance from the C-6 hydroxyl group of the sugar, which after cleavage will contain the new reducing end. In the D229N/E257Q double mutant structure, two alpha-cyclodextrins are observed to replace two maltoses at the E-domain, thus providing structural information on product inhibition via binding to the enzyme's raw starch binding domain.

PubMed: 7493956
DOI: 10.1074/jbc.270.49.29256

実験手法

X-RAY DIFFRACTION (2.2 Å)