Oxygen reactivity of the biferrous site in the de novo designed four helix bundle peptide DFsc: nature of the "intermediate" and reaction mechanism.
The DFsc and DFscE11D de novo designed protein scaffolds support biomimetic diiron cofactor sites that react with dioxygen forming a 520 nm "intermediate" species with an apparent pseudo-first-order formation rate constant of 2.2 and 4.8 s-1, respectively. Resonance Raman spectroscopy shows that this absorption feature is due to a phenolate-to-ferric charge transfer transition arising from a single tyrosine residue coordinating terminally to one of the ferric ions in the site. Phenol coordination could provide a proton to promote rapid loss of a putative peroxo species.
Department of Biochemistry and Biophysics, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6059, USA.
Jennifer R
JR
Calhoun
Caleb B
CB
Bell
Thomas J
TJ
Smith
Thomas J
TJ
Thamann
William F
WF
DeGrado
Edward I
EI
Solomon
D040761:Biomimetic Materials / Q000737:chemistry / Q000378:metabolism; D002570:Ceruloplasmin / Q000737:chemistry / Q000378:metabolism; D005290:Ferric Compounds / Q000737:chemistry / Q000378:metabolism; D005293:Ferritins / Q000737:chemistry / Q000378:metabolism; D005296:Ferrous Compounds / Q000737:chemistry* / Q000378:metabolism; D007700:Kinetics; D019159:Nonheme Iron Proteins / Q000737:chemistry* / Q000378:metabolism; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry* / Q000378:metabolism; D010636:Phenols / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary; D013059:Spectrum Analysis, Raman / Q000379:methods; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism
D005290:Ferric Compounds; D005296:Ferrous Compounds; D019159:Nonheme Iron Proteins; D010636:Phenols; D014443:Tyrosine; D005293:Ferritins; D002570:Ceruloplasmin; D010100:Oxygen