1E4N

Crystal structure of the inactive mutant Monocot (Maize ZMGlu1) beta-glucosidase ZMGluE191D in complex with the natural aglycone DIMBOA

1E4N の概要

• エントリーDOI: 10.2210/pdb1e4n/pdb
• 関連するPDBエントリー: 1CBG 1E1E 1E1F 1E4L 1E55 1E56
• 分子名称: BETA-GLUCOSIDASE, 2,4-DIHYDROXY-7-(METHYLOXY)-2H-1,4-BENZOXAZIN-3(4H)-ONE (3 entities in total)
• 機能のキーワード: glycoside hydrolase, beta-glucosidase, family 1, retention of the anomeric configuration, inactive mutant e191d, hydrolase complex with dimboa, hydrolase
• 由来する生物種: ZEA MAYS (MAIZE)
• 細胞内の位置: Plastid, chloroplast: P49235
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 117339.19

構造登録者

Czjzek, M.,Cicek, M.,Bevan, D.R.,Zamboni, V.,Henrissat, B.,Esen, A. (登録日: 2000-07-11, 公開日: 2000-12-11, 最終更新日: 2024-11-06)

主引用文献

Czjzek, M.,Cicek, M.,Zamboni, V.,Bevan, D.R.,Henrissat, B.,Esen, A.
The Mechanism of Substrate (Aglycone) Specificity in Beta -Glucosidases is Revealed by Crystal Structures of Mutant Maize Beta -Glucosidase-Dimboa, -Dimboaglc, and -Dhurrin Complexes
Proc.Natl.Acad.Sci.USA, 97:13555-, 2000

PubMed Abstract: The mechanism and the site of substrate (i.e., aglycone) recognition and specificity were investigated in maize beta-glucosidase (Glu1) by x-ray crystallography by using crystals of a catalytically inactive mutant (Glu1E191D) in complex with the natural substrate 2-O-beta-d-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOAGlc), the free aglycone DIMBOA, and competitive inhibitor para-hydroxy-S-mandelonitrile beta-glucoside (dhurrin). The structures of these complexes and of the free enzyme were solved at 2.1-, 2.1-, 2.0-, and 2.2-A resolution, respectively. The structural data from the complexes allowed us to visualize an intact substrate, free aglycone, or a competitive inhibitor in the slot-like active site of a beta-glucosidase. These data show that the aglycone moiety of the substrate is sandwiched between W378 on one side and F198, F205, and F466 on the other. Thus, specific conformations of these four hydrophobic amino acids and the shape of the aglycone-binding site they form determine aglycone recognition and substrate specificity in Glu1. In addition to these four residues, A467 interacts with the 7-methoxy group of DIMBOA. All residues but W378 are variable among beta-glucosidases that differ in substrate specificity, supporting the conclusion that these sites are the basis of aglycone recognition and binding (i.e., substrate specificity) in beta-glucosidases. The data also provide a plausible explanation for the competitive binding of dhurrin to maize beta-glucosidases with high affinity without being hydrolyzed.

PubMed: 11106394
DOI: 10.1073/PNAS.97.25.13555

実験手法

X-RAY DIFFRACTION (2.1 Å)