2QB2

Structural Studies Reveal the Inactivation of E. coli L-aspartate aminotransferase by (s)-4,5-dihydro-2thiophenecarboylic acid (SADTA) via two mechanisms (at pH 7.0).

2QB2 の概要

• エントリーDOI: 10.2210/pdb2qb2/pdb
• 関連するPDBエントリー: 2Q7W 2QA3 2QB3
• 分子名称: Aspartate aminotransferase, SULFATE ION, 4-[({3-HYDROXY-2-METHYL-5-[(PHOSPHONOOXY)METHYL]PYRIDIN-4-YL}METHYL)AMINO]THIOPHENE-2-CARBOXYLIC ACID, ... (6 entities in total)
• 機能のキーワード: mechanism-based inactivator, ph dependence, aspartate aminotransferase, sadta, plp, transferase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Cytoplasm: P00509
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 45664.07

構造登録者

Liu, D.,Pozharski, E.,Lepore, B.,Fu, M.,Silverman, R.B.,Petsko, G.A.,Ringe, D. (登録日: 2007-06-15, 公開日: 2007-12-04, 最終更新日: 2023-08-30)

主引用文献

Liu, D.,Pozharski, E.,Lepore, B.W.,Fu, M.,Silverman, R.B.,Petsko, G.A.,Ringe, D.
Inactivation of Escherichia coli L-aspartate aminotransferase by (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid reveals "a tale of two mechanisms".
Biochemistry, 46:10517-10527, 2007

PubMed Abstract: As a mechanism-based inactivator of PLP-enzymes, (S)-4-amino-4,5-dihydro-2-thiophenecarboxylic acid (SADTA) was cocrystallized with Escherichia coli aspartate aminotransferase (l-AspAT) at a series of pH values ranging from 6 to 8. Five structural models with high resolution (1.4-1.85 A) were obtained for l-AspAT-SADTA complexes at pH 6.0, 6.5, 7.0, 7.5, and 8.0. Electron densities of the models showed that two different adducts had formed in the active sites. One adduct was formed from SADTA covalently linked to pyridoxal 5'-phosphate (PLP) while the other adduct was formed with the inhibitor covalently linked to Lysine246,1 the active site lysine. Moreover, there is a strong indication based on the electron densities that the occurrence of the two adducts is pH dependent. We conclude that SADTA inactivates l-AspAT via two different mechanisms based on the binding direction of the inactivator. Additionally, the structural models also show pH dependence of the protein structure itself, which provided detailed mechanistic implications for l-AspAT.

PubMed: 17713924
DOI: 10.1021/bi700663n

実験手法

X-RAY DIFFRACTION (1.7 Å)