4TYX

Structure of aquoferric sperm whale myoglobin L29H/F33Y/F43H/S92A mutant

4TYX の概要

• エントリーDOI: 10.2210/pdb4tyx/pdb
• 分子名称: Myoglobin, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: globin, oxidoreductase, artificial, engineered, oxygen transport
• 由来する生物種: Physeter catodon (Sperm whale)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 17867.40

構造登録者

Bhagi-Damodaran, A.,Petrik, I.D.,Robinson, H.,Lu, Y. (登録日: 2014-07-09, 公開日: 2014-08-13, 最終更新日: 2023-09-27)

主引用文献

Bhagi-Damodaran, A.,Petrik, I.D.,Marshall, N.M.,Robinson, H.,Lu, Y.
Systematic tuning of heme redox potentials and its effects on O2 reduction rates in a designed oxidase in myoglobin.
J.Am.Chem.Soc., 136:11882-11885, 2014

PubMed Abstract: Cytochrome c Oxidase (CcO) is known to catalyze the reduction of O2 to H2O efficiently with a much lower overpotential than most other O2 reduction catalysts. However, methods by which the enzyme fine-tunes the reduction potential (E°) of its active site and the corresponding influence on the O2 reduction activity are not well understood. In this work, we report systematic tuning of the heme E° in a functional model of CcO in myoglobin containing three histidines and one tyrosine in the distal pocket of heme. By removing hydrogen-bonding interactions between Ser92 and the proximal His ligand and a heme propionate, and increasing hydrophobicity of the heme pocket through Ser92Ala mutation, we have increased the heme E° from 95 ± 2 to 123 ± 3 mV. Additionally, replacing the native heme b in the CcO mimic with heme a analogs, diacetyl, monoformyl, and diformyl hemes, that posses electron-withdrawing groups, resulted in higher E° values of 175 ± 5, 210 ± 6, and 320 ± 10 mV, respectively. Furthermore, O2 consumption studies on these CcO mimics revealed a strong enhancement in O2 reduction rates with increasing heme E°. Such methods of tuning the heme E° through a combination of secondary sphere mutations and heme substitutions can be applied to tune E° of other heme proteins, allowing for comprehensive investigations of the relationship between E° and enzymatic activity.

PubMed: 25076049
DOI: 10.1021/ja5054863

実験手法

X-RAY DIFFRACTION (1.64 Å)