2NT9

Crystal structure of pectin methylesterase D178A mutant in complex with hexasaccharide IV

2NT9 の概要

• エントリーDOI: 10.2210/pdb2nt9/pdb
• 関連するPDBエントリー: 1QJV 2NSP 2NST 2NT6 2NTB 2NTP 2NTQ
• 分子名称: Pectinesterase A, alpha-D-galactopyranuronic acid-(1-4)-methyl alpha-D-galactopyranuronate-(1-4)-methyl alpha-D-galactopyranuronate-(1-4)-methyl alpha-D-galactopyranuronate-(1-4)-methyl alpha-D-galactopyranuronate-(1-4)-alpha-D-galactopyranuronic acid (3 entities in total)
• 機能のキーワード: michaelis complex, hydrolase
• 由来する生物種: Erwinia chrysanthemi
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 76161.30

構造登録者

Fries, M.,Brocklehurst, K.,Shevchik, V.E.,Pickersgill, R.W. (登録日: 2006-11-07, 公開日: 2007-09-18, 最終更新日: 2024-11-06)

主引用文献

Fries, M.,Ihrig, J.,Brocklehurst, K.,Shevchik, V.E.,Pickersgill, R.W.
Molecular basis of the activity of the phytopathogen pectin methylesterase.
Embo J., 26:3879-3887, 2007

PubMed Abstract: We provide a mechanism for the activity of pectin methylesterase (PME), the enzyme that catalyses the essential first step in bacterial invasion of plant tissues. The complexes formed in the crystal using specifically methylated pectins, together with kinetic measurements of directed mutants, provide clear insights at atomic resolution into the specificity and the processive action of the Erwinia chrysanthemi enzyme. Product complexes provide additional snapshots along the reaction coordinate. We previously revealed that PME is a novel aspartic-esterase possessing parallel beta-helix architecture and now show that the two conserved aspartates are the nucleophile and general acid-base in the mechanism, respectively. Other conserved residues at the catalytic centre are shown to be essential for substrate binding or transition state stabilisation. The preferential binding of methylated sugar residues upstream of the catalytic site, and demethylated residues downstream, drives the enzyme along the pectin molecule and accounts for the sequential pattern of demethylation produced by both bacterial and plant PMEs.

PubMed: 17717531
DOI: 10.1038/sj.emboj.7601816

実験手法

X-RAY DIFFRACTION (1.9 Å)