1VLQ

Crystal structure of Acetyl xylan esterase (TM0077) from Thermotoga maritima at 2.10 A resolution

1VLQ の概要

• エントリーDOI: 10.2210/pdb1vlq/pdb
• 分子名称: acetyl xylan esterase, GLYCEROL (3 entities in total)
• 機能のキーワード: tm0077, acetyl xylan esterase, structural genomics, jcsg, protein structure initiative, psi, joint center for structural genomics, hydrolase
• 由来する生物種: Thermotoga maritima
• 細胞内の位置: Cytoplasm : Q9WXT2
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 467986.30

構造登録者

Joint Center for Structural Genomics (JCSG) (登録日: 2004-08-09, 公開日: 2004-08-24, 最終更新日: 2024-10-30)

主引用文献

Levisson, M.,Han, G.W.,Deller, M.C.,Xu, Q.,Biely, P.,Hendriks, S.,Ten Eyck, L.F.,Flensburg, C.,Roversi, P.,Miller, M.D.,McMullan, D.,von Delft, F.,Kreusch, A.,Deacon, A.M.,van der Oost, J.,Lesley, S.A.,Elsliger, M.A.,Kengen, S.W.,Wilson, I.A.
Functional and structural characterization of a thermostable acetyl esterase from Thermotoga maritima.
Proteins, 80:1545-1559, 2012

PubMed Abstract: TM0077 from Thermotoga maritima is a member of the carbohydrate esterase family 7 and is active on a variety of acetylated compounds, including cephalosporin C. TM0077 esterase activity is confined to short-chain acyl esters (C2-C3), and is optimal around 100°C and pH 7.5. The positional specificity of TM0077 was investigated using 4-nitrophenyl-β-D-xylopyranoside monoacetates as substrates in a β-xylosidase-coupled assay. TM0077 hydrolyzes acetate at positions 2, 3, and 4 with equal efficiency. No activity was detected on xylan or acetylated xylan, which implies that TM0077 is an acetyl esterase and not an acetyl xylan esterase as currently annotated. Selenomethionine-substituted and native structures of TM0077 were determined at 2.1 and 2.5 Å resolution, respectively, revealing a classic α/β-hydrolase fold. TM0077 assembles into a doughnut-shaped hexamer with small tunnels on either side leading to an inner cavity, which contains the six catalytic centers. Structures of TM0077 with covalently bound phenylmethylsulfonyl fluoride and paraoxon were determined to 2.4 and 2.1 Å, respectively, and confirmed that both inhibitors bind covalently to the catalytic serine (Ser188). Upon binding of inhibitor, the catalytic serine adopts an altered conformation, as observed in other esterase and lipases, and supports a previously proposed catalytic mechanism in which Ser hydroxyl rotation prevents reversal of the reaction and allows access of a water molecule for completion of the reaction.

PubMed: 22411095
DOI: 10.1002/prot.24041

実験手法

X-RAY DIFFRACTION (2.1 Å)