1TTH

Aspartate Transcarbamoylase Catalytic Chain Mutant Glu50Ala Complexed with N-(Phosphonacetyl-L-Aspartate) (PALA)

1TTH の概要

• エントリーDOI: 10.2210/pdb1tth/pdb
• 関連するPDBエントリー: 1D09 1TU0
• 分子名称: Aspartate carbamoyltransferase catalytic chain, Aspartate carbamoyltransferase regulatory chain, N-(PHOSPHONACETYL)-L-ASPARTIC ACID, ... (5 entities in total)
• 機能のキーワード: site-specific mutagenesis, domain closure, allosteric transition, hydrolase-hydrolase regulator complex, hydrolase/hydrolase regulator
• 由来する生物種: Escherichia coli; 詳細
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 103486.45

構造登録者

Stieglitz, K.,Stec, B.,Baker, D.P.,Kantrowitz, E.R. (登録日: 2004-06-22, 公開日: 2004-07-20, 最終更新日: 2023-08-23)

主引用文献

Stieglitz, K.,Stec, B.,Baker, D.P.,Kantrowitz, E.R.
Monitoring the Transition from the T to the R State in E.coli Aspartate Transcarbamoylase by X-ray Crystallography: Crystal Structures of the E50A Mutant Enzyme in Four Distinct Allosteric States.
J.Mol.Biol., 341:853-868, 2004

PubMed Abstract: A detailed description of the transition that allosteric enzymes undergo constitutes a major challenge in structural biology. We have succeeded in trapping four distinct allosteric states of a mutant enzyme of Escherichia coli aspartate transcarbomylase and determining their structures by X-ray crystallography. The mutant version of aspartate transcarbamoylase in which Glu50 in the catalytic chains was replaced by Ala destabilizes the native R state and shifts the equilibrium towards the T state. This behavior allowed the use of substrate analogs such as phosphonoacetamide and malonate to trap the enzyme in T-like and R-like structures that are distinct from the T-state structure of the wild-type enzyme (as represented by the structure of the enzyme with CTP bound and the R-state structure as represented by the structure with N-(phosphonacetyl)-L-aspartate bound). These structures shed light on the nature and the order of internal structural rearrangements during the transition from the T to the R state. They also suggest an explanation for diminished activity of the E50A enzyme and for the change in reaction mechanism from ordered to random for this mutant enzyme.

PubMed: 15288791
DOI: 10.1016/j.jmb.2004.06.002

実験手法

X-RAY DIFFRACTION (2.8 Å)