5YEM

CATPO mutant - T188F

5YEM の概要

• エントリーDOI: 10.2210/pdb5yem/pdb
• 分子名称: Catalase, CALCIUM ION, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
• 機能のキーワード: catalase, phenol oxidase, lateral channel, mutant, oxidoreductase
• 由来する生物種: Mycothermus thermophilus
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 302075.14

構造登録者

Yuzugullu Karakus, Y.,Balci, S.,Goc, G.,Pearson, A.R.,Yorke, B. (登録日: 2017-09-18, 公開日: 2018-07-18, 最終更新日: 2024-02-14)

主引用文献

Yuzugullu, Y.K.,Goc, G.,Zengin, M.K.,Balci, S.U.,Yorke, B.A.,Pearson, A.R.
Investigation of how gate residues in the main channel affect the catalytic activity of Scytalidium thermophilum catalase.
Acta Crystallogr D Struct Biol, 80:101-112, 2024

PubMed Abstract: Catalase is an antioxidant enzyme that breaks down hydrogen peroxide (HO) into molecular oxygen and water. In all monofunctional catalases the pathway that HO takes to the catalytic centre is via the `main channel'. However, the structure of this channel differs in large-subunit and small-subunit catalases. In large-subunit catalases the channel is 15 Å longer and consists of two distinct parts, including a hydrophobic lower region near the heme and a hydrophilic upper region where multiple HO routes are possible. Conserved glutamic acid and threonine residues are located near the intersection of these two regions. Mutations of these two residues in the Scytalidium thermophilum catalase had no significant effect on catalase activity. However, the secondary phenol oxidase activity was markedly altered, with k and k/K values that were significantly increased in the five variants E484A, E484I, T188D, T188I and T188F. These variants also showed a lower affinity for inhibitors of oxidase activity than the wild-type enzyme and a higher affinity for phenolic substrates. Oxidation of heme b to heme d did not occur in most of the studied variants. Structural changes in solvent-chain integrity and channel architecture were also observed. In summary, modification of the main-channel gate glutamic acid and threonine residues has a greater influence on the secondary activity of the catalase enzyme, and the oxidation of heme b to heme d is predominantly inhibited by their conversion to aliphatic and aromatic residues.

PubMed: 38265876
DOI: 10.1107/S2059798323011063

実験手法

X-RAY DIFFRACTION (1.49 Å)