4IJ4

Crystal Structure of a Family GH19 chitinase from Bryum coronatum in complex with (GlcNAc)4

4IJ4 の概要

• エントリーDOI: 10.2210/pdb4ij4/pdb
• 関連するPDBエントリー: 3WH1
• 分子名称: Chitinase A, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 1,2-ETHANEDIOL, ... (4 entities in total)
• 機能のキーワード: chitinase, hydrolase, carbohydrate
• 由来する生物種: Bryum coronatum
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 23877.50

構造登録者

Numata, T.,Umemoto, N.,Ohnuma, T.,Fukamizo, T. (登録日: 2012-12-21, 公開日: 2014-03-26, 最終更新日: 2024-11-06)

主引用文献

Ohnuma, T.,Umemoto, N.,Nagata, T.,Shinya, S.,Numata, T.,Taira, T.,Fukamizo, T.
Crystal structure of a "loopless" GH19 chitinase in complex with chitin tetrasaccharide spanning the catalytic center.
Biochim.Biophys.Acta, 1844:793-802, 2014

PubMed Abstract: The structure of a GH19 chitinase from the moss Bryum coronatum (BcChi-A) in complex with the substrate was examined by X-ray crystallography and NMR spectroscopy in solution. The X-ray crystal structure of the inactive mutant of BcChi-A (BcChi-A-E61A) liganded with chitin tetramer (GlcNAc)4 revealed a clear electron density of the tetramer bound to subsites -2, -1, +1, and +2. Individual sugar residues were recognized by several amino acids at these subsites through a number of hydrogen bonds. This is the first crystal structure of GH19 chitinase liganded with oligosaccharide spanning the catalytic center. NMR titration experiments of chitin oligosaccharides into the BcChi-A-E61A solution showed that the binding mode observed in the crystal structure is similar to that in solution. The C-1 carbon of -1 GlcNAc, the Oε1 atom of the catalytic base (Glu70), and the Oγ atom of Ser102 form a "triangle" surrounding the catalytic water, and the arrangement structurally validated the proposed catalytic mechanism of GH19 chitinases. The glycosidic linkage between -1 and +1 sugars was found to be twisted and under strain. This situation may contribute to the reduction of activation energy for hydrolysis. The complex structure revealed a more refined mechanism of the chitinase catalysis.

PubMed: 24582745
DOI: 10.1016/j.bbapap.2014.02.013

実験手法

X-RAY DIFFRACTION (1.58 Å)