4LNC

Neutron structure of the cyclic glucose bound Xylose Isomerase E186Q mutant

4LNC の概要

• エントリーDOI: 10.2210/pdb4lnc/pdb
• 分子名称: Xylose isomerase, alpha-D-glucopyranose, MANGANESE (II) ION, ... (5 entities in total)
• 機能のキーワード: isomerase, mutant enzyme, metalloenzyme, two metal binding sites
• 由来する生物種: Streptomyces rubiginosus
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 43509.61

構造登録者

Munshi, P.,Meilleur, F.,Myles, D. (登録日: 2013-07-11, 公開日: 2014-02-12, 最終更新日: 2025-11-12)

主引用文献

Munshi, P.,Snell, E.H.,van der Woerd, M.J.,Judge, R.A.,Myles, D.A.,Ren, Z.,Meilleur, F.
Neutron structure of the cyclic glucose-bound xylose isomerase E186Q mutant.
Acta Crystallogr.,Sect.D, 70:414-420, 2014

PubMed Abstract: Ketol-isomerases catalyze the reversible isomerization between aldoses and ketoses. D-Xylose isomerase carries out the first reaction in the catabolism of D-xylose, but is also able to convert D-glucose to D-fructose. The first step of the reaction is an enzyme-catalyzed ring opening of the cyclic substrate. The active-site amino-acid acid/base pair involved in ring opening has long been investigated and several models have been proposed. Here, the structure of the xylose isomerase E186Q mutant with cyclic glucose bound at the active site, refined against joint X-ray and neutron diffraction data, is reported. Detailed analysis of the hydrogen-bond networks at the active site of the enzyme suggests that His54, which is doubly protonated, is poised to protonate the glucose O5 position, while Lys289, which is neutral, promotes deprotonation of the glucose O1H hydroxyl group via an activated water molecule. The structure also reveals an extended hydrogen-bonding network that connects the conserved residues Lys289 and Lys183 through three structurally conserved water molecules and residue 186, which is a glutamic acid to glutamine mutation.

PubMed: 24531475
DOI: 10.1107/S1399004713029684

実験手法

NEUTRON DIFFRACTION (2.19 Å)
X-RAY DIFFRACTION (1.84 Å)