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Stabilization of the peroxy intermediate in the oxygen splitting reaction of cytochrome cbb3

Tutkimustuotosvertaisarvioitu

Yksityiskohdat

AlkuperäiskieliEnglanti
Sivut813-818
Sivumäärä6
JulkaisuBiochimica et Biophysica Acta: Bioenergetics
Vuosikerta1807
Numero7
DOI - pysyväislinkit
TilaJulkaistu - heinäkuuta 2011
OKM-julkaisutyyppiA1 Alkuperäisartikkeli

Tiivistelmä

The proton-pumping cbb3-type cytochrome c oxidases catalyze cell respiration in many pathogenic bacteria. For reasons not yet understood, the apparent dioxygen (O2) affinity in these enzymes is very high relative to other members of the heme-copper oxidase (HCO) superfamily. Based on density functional theory (DFT) calculations on intermediates of the oxygen scission reaction in active-site models of cbb3- and aa 3-type oxidases, we find that a transient peroxy intermediate (I P, Fe[III]-OOH-) is ~ 6 kcal/mol more stable in the former case, resulting in more efficient kinetic trapping of dioxygen and hence in a higher apparent oxygen affinity. The major molecular basis for this stabilization is a glutamate residue, polarizing the proximal histidine ligand of heme b3 in the active site.

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