1E8D

MECHANISTIC ASPECTS OF CYANOGENESIS FROM ACTIVE SITE MUTANT SER80ALA OF HYDROXYNITRILE LYASE FROM MANIHOT ESCULENTA IN COMPLEX WITH ACETONE CYANOHYDRIN

1E8D の概要

• エントリーDOI: 10.2210/pdb1e8d/pdb
• 関連するPDBエントリー: 1DWO 1DWP 1DWQ 1E89
• 分子名称: HYDROXYNITRILE LYASE, 2-HYDROXY-2-METHYLPROPANENITRILE (3 entities in total)
• 機能のキーワード: lyase, hydroxynitrile lyase, active site mutant, acetone cyanohydrin complex
• 由来する生物種: MANIHOT ESCULENTA (CASSAVA)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 59978.83

構造登録者

Lauble, H.,Miehlich, B.,Foerster, S.,Wajant, H.,Effenberger, F. (登録日: 2000-09-19, 公開日: 2001-08-17, 最終更新日: 2023-12-13)

主引用文献

Lauble, H.,Miehlich, B.,Forster, S.,Wajant, H.,Effenberger, F.
Mechanistic Aspects of Cyanogenesis from Active-Site Mutant Ser80Ala of Hydroxynitrile Lyase from Manihot Esculenta in Complex with Acetone Cyanohydrin.
Protein Sci., 10:1015-, 2001

PubMed Abstract: The structure and function of hydroxynitrile lyase from Manihot esculenta (MeHNL) have been analyzed by X-ray crystallography and site-directed mutagenesis. The crystal structure of the MeHNL-S80A mutant enzyme has been refined to an R-factor of 18.0% against diffraction data to 2.1-A resolution. The three-dimensional structure of the MeHNL-S80A-acetone cyanohydrin complex was determined at 2.2-A resolution and refined to an R-factor of 18.7%. Thr11 and Cys81 involved in substrate binding have been substituted by Ala in site-directed mutagenesis. The kinetic measurements of these mutant enzymes are presented. Combined with structural data, the results support a mechanism for cyanogenesis in which His236 as a general base abstracts a proton from Ser80, thereby allowing proton transfer from the hydroxyl group of acetone cyanohydrin to Ser80. The His236 imidazolium cation then facilitates the leaving of the nitrile group by proton donating.

PubMed: 11316882
DOI: 10.1110/PS.01301

実験手法

X-RAY DIFFRACTION (2.2 Å)