5HAV

Sperm whale myoglobin mutant L29H F33Y F43H (F33Y CuBMb) with oxygen bound

Summary for 5HAV

• Entry DOI: 10.2210/pdb5hav/pdb
• Related: 4FWX
• Descriptor: Myoglobin, PROTOPORPHYRIN IX CONTAINING FE, OXYGEN MOLECULE, ... (4 entities in total)
• Functional Keywords: oxidase, oxidoreductase
• Biological source: Physeter catodon (Sperm whale)
• Total number of polymer chains: 1
• Total formula weight: 17915.40

Authors

Petrik, I.D.,Lu, Y. (deposition date: 2015-12-31, release date: 2016-01-13, Last modification date: 2023-09-27)

Primary citation

Petrik, I.D.,Davydov, R.,Ross, M.,Zhao, X.,Hoffman, B.,Lu, Y.
Spectroscopic and Crystallographic Evidence for the Role of a Water-Containing H-Bond Network in Oxidase Activity of an Engineered Myoglobin.
J.Am.Chem.Soc., 138:1134-1137, 2016

PubMed Abstract: Heme-copper oxidases (HCOs) catalyze efficient reduction of oxygen to water in biological respiration. Despite progress in studying native enzymes and their models, the roles of non-covalent interactions in promoting this activity are still not well understood. Here we report EPR spectroscopic studies of cryoreduced oxy-F33Y-CuBMb, a functional model of HCOs engineered in myoglobin (Mb). We find that cryoreduction at 77 K of the O2-bound form, trapped in the conformation of the parent oxyferrous form, displays a ferric-hydroperoxo EPR signal, in contrast to the cryoreduced oxy-wild-type (WT) Mb, which is unable to deliver a proton and shows a signal from the peroxo-ferric state. Crystallography of oxy-F33Y-CuBMb reveals an extensive H-bond network involving H2O molecules, which is absent from oxy-WTMb. This H-bonding proton-delivery network is the key structural feature that transforms the reversible oxygen-binding protein, WTMb, into F33Y-CuBMb, an oxygen-activating enzyme that reduces O2 to H2O. These results provide direct evidence of the importance of H-bond networks involving H2O in conferring enzymatic activity to a designed protein. Incorporating such extended H-bond networks in designing other metalloenzymes may allow us to confer and fine-tune their enzymatic activities.

PubMed: 26716352
DOI: 10.1021/jacs.5b12004

Experimental method

X-RAY DIFFRACTION (1.268 Å)