2HBX

Crystal Structure of alpha-Amino-beta-Carboxymuconate-epsilon-Semialdehyde-Decarboxylase (ACMSD)

2HBX の概要

• エントリーDOI: 10.2210/pdb2hbx/pdb
• 関連するPDBエントリー: 2HBV
• 分子名称: 2-amino-3-carboxymuconate 6-semialdehyde decarboxylase, COBALT (II) ION (3 entities in total)
• 機能のキーワード: acmsd, tim-barrel, decarboxylase, metaloenzyme, lyase
• 由来する生物種: Pseudomonas fluorescens
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 74485.05

構造登録者

Martynowski, D.,Eyobo, Y.,Li, T.,Yang, K.,Liu, A.,Zhang, H. (登録日: 2006-06-14, 公開日: 2006-09-19, 最終更新日: 2024-02-14)

主引用文献

Martynowski, D.,Eyobo, Y.,Li, T.,Yang, K.,Liu, A.,Zhang, H.
Crystal Structure of alpha-Amino-beta-carboxymuconate-epsilon-semialdehyde Decarboxylase: Insight into the Active Site and Catalytic Mechanism of a Novel Decarboxylation Reaction.
Biochemistry, 45:10412-10421, 2006

PubMed Abstract: Alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) is a widespread enzyme found in many bacterial species and all currently sequenced eukaryotic organisms. It occupies a key position at the branching point of two metabolic pathways: the tryptophan to quinolinate pathway and the bacterial 2-nitrobenzoic acid degradation pathway. The activity of ACMSD determines whether the metabolites in both pathways are converted to quinolinic acid for NAD biosynthesis or to acetyl-CoA for the citric acid cycle. Here we report the first high-resolution crystal structure of ACMSD from Pseudomonas fluorescens which validates our previous predictions that this enzyme is a member of the metal-dependent amidohydrolase superfamily of the (beta/alpha)(8) TIM barrel fold. The structure of the enzyme in its native form, determined at 1.65 A resolution, reveals the precise spatial arrangement of the active site metal center and identifies a potential substrate-binding pocket. The identity of the native active site metal was determined to be Zn. Also determined was the structure of the enzyme complexed with cobalt at 2.50 A resolution. The hydrogen bonding network around the metal center suggests that Arg51 and His228 may play important roles in catalysis. The metal center configuration of PfACMSD is very similar to that of Zn-dependent adenosine deaminase and Fe-dependent cytosine deaminase, suggesting that ACMSD may share certain similarities in its catalytic mechanism with these enzymes. These data enable us to propose possible catalytic mechanisms for ACMSD which appear to be unprecedented among all currently characterized decarboxylases.

PubMed: 16939194
DOI: 10.1021/bi060903q

実験手法

X-RAY DIFFRACTION (2.5 Å)