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3C20

Crystal Structure of Threonine-sensitive Aspartokinase from Methanococcus jannaschii with L-aspartate

3C20 の概要
エントリーDOI10.2210/pdb3c20/pdb
関連するPDBエントリー3C1M 3C1N
分子名称Probable aspartokinase, ASPARTIC ACID, FORMIC ACID, ... (4 entities in total)
機能のキーワードkinase, allosetric inhibition, theronine-sensitive, act domain, amino-acid biosynthesis, threonine biosynthesis, transferase
由来する生物種Methanocaldococcus jannaschii
タンパク質・核酸の鎖数2
化学式量合計103272.51
構造登録者
Liu, X.,Pavlovsky, A.G.,Viola, R.E. (登録日: 2008-01-24, 公開日: 2008-04-29, 最終更新日: 2023-08-30)
主引用文献Liu, X.,Pavlovsky, A.G.,Viola, R.E.
The Structural Basis for Allosteric Inhibition of a Threonine-sensitive Aspartokinase.
J.Biol.Chem., 283:16216-16225, 2008
Cited by
PubMed Abstract: The commitment step to the aspartate pathway of amino acid biosynthesis is the phosphorylation of aspartic acid catalyzed by aspartokinase (AK). Most microorganisms and plants have multiple forms of this enzyme, and many of these isofunctional enzymes are subject to feedback regulation by the end products of the pathway. However, the archeal species Methanococcus jannaschii has only a single, monofunctional form of AK. The substrate l-aspartate binds to this recombinant enzyme in two different orientations, providing the first structural evidence supporting the relaxed regiospecificity previously observed with several alternative substrates of Escherichia coli AK ( Angeles, T. S., Hunsley, J. R., and Viola, R. E. (1992) Biochemistry 31, 799-805 ). Binding of the nucleotide substrate triggers significant domain movements that result in a more compact quaternary structure. In contrast, the highly cooperative binding of the allosteric regulator l-threonine to multiple sites on this dimer of dimers leads to an open enzyme structure. A comparison of these structures supports a mechanism for allosteric regulation in which the domain movements induced by threonine binding causes displacement of the substrates from the enzyme, resulting in a relaxed, inactive conformation.
PubMed: 18334478
DOI: 10.1074/jbc.M800760200
主引用文献が同じPDBエントリー
実験手法
X-RAY DIFFRACTION (2.7 Å)
構造検証レポート
Validation report summary of 3c20
検証レポート(詳細版)ダウンロードをダウンロード

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件を2025-07-23に公開中

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