5HMF

Crystal structure of triazine hydrolase variant (P214T/Y215H/E241Q)

5HMF の概要

• エントリーDOI: 10.2210/pdb5hmf/pdb
• 関連するPDBエントリー: 4LH8 5HMD 5HME
• 分子名称: Triazine hydrolase, ZINC ION (3 entities in total)
• 機能のキーワード: amidohydrolase, hydrolase
• 由来する生物種: Arthrobacter aurescens
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 100324.66

構造登録者

Sugrue, E.,Carr, P.D.,Jackson, C.J. (登録日: 2016-01-16, 公開日: 2016-11-02, 最終更新日: 2023-09-27)

主引用文献

Sugrue, E.,Carr, P.D.,Scott, C.,Jackson, C.J.
Active Site Desolvation and Thermostability Trade-Offs in the Evolution of Catalytically Diverse Triazine Hydrolases.
Biochemistry, 55:6304-6313, 2016

PubMed Abstract: The desolvation of ionizable residues in the active sites of enzymes and the subsequent effects on catalysis and thermostability have been studied in model systems, yet little about how enzymes can naturally evolve to include active sites with highly reactive and desolvated charges is known. Variants of triazine hydrolase (TrzN) with significant differences in their active sites have been isolated from different bacterial strains: TrzN from Nocardioides sp. strain MTD22 contains a catalytic glutamate residue (Glu241) that is surrounded by hydrophobic and aromatic second-shell residues (Pro214 and Tyr215), whereas TrzN from Nocardioides sp. strain AN3 has a noncatalytic glutamine residue (Gln241) at an equivalent position, surrounded by hydrophilic residues (Thr214 and His215). To understand how and why these variants have evolved, a series of TrzN mutants were generated and characterized. These results show that desolvation by second-shell residues increases the pK of Glu241, allowing it to act as a general acid at neutral pH. However, significant thermostability trade-offs are required to incorporate the ionizable Glu241 in the active site and to then enclose it in a hydrophobic microenvironment. Analysis of high-resolution crystal structures shows that there are almost no structural changes to the overall configuration of the active site due to these mutations, suggesting that the changes in activity and thermostability are purely based on the altered electrostatics. The natural evolution of these enzyme isoforms provides a unique system in which to study the fundamental process of charged residue desolvation in enzyme catalysis and its relative contribution to the creation and evolution of an enzyme active site.

PubMed: 27768291
DOI: 10.1021/acs.biochem.6b00731

実験手法

X-RAY DIFFRACTION (1.84 Å)