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4TYX

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

Summary for 4TYX
Entry DOI10.2210/pdb4tyx/pdb
DescriptorMyoglobin, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
Functional Keywordsglobin, oxidoreductase, artificial, engineered, oxygen transport
Biological sourcePhyseter catodon (Sperm whale)
Total number of polymer chains1
Total formula weight17867.40
Authors
Bhagi-Damodaran, A.,Petrik, I.D.,Robinson, H.,Lu, Y. (deposition date: 2014-07-09, release date: 2014-08-13, Last modification date: 2023-09-27)
Primary citationBhagi-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
Cited by
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
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (1.64 Å)
Structure validation

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