Ultrafast ligand binding dynamics in the active site of native bacterial nitric oxide reductase

Abstract : The active site of nitric oxide reductase from Paracoccus denitrificans contains heme and non-heme iron and is evolutionarily related to heme-copper oxidases. The CO and NO dynamics in the active site were investigated using ultrafast transient absorption spectroscopy. We find that, upon photodissociation from the active site heme, 20% of the CO rebinds in 170 ps, suggesting that not all the CO transiently binds to the non-heme iron. The remaining 80% does not rebind within 4 ns and likely migrates out of the active site without transient binding to the non-heme iron. Rebinding of NO to ferrous heme takes place in approximately 13 ps. Our results reveal that heme-ligand recombination in this enzyme is considerably faster than in heme-copper oxidases and are consistent with a more confined configuration of the active site.
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https://hal.archives-ouvertes.fr/hal-00324232
Contributor : Laure Lachapelle <>
Submitted on : Wednesday, September 24, 2008 - 2:22:00 PM
Last modification on : Thursday, February 7, 2019 - 4:33:12 PM

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Sofia Kapetanaki, Sara Field, Ross Hughes, Nicholas Watmough, Ursula Liebl, et al.. Ultrafast ligand binding dynamics in the active site of native bacterial nitric oxide reductase. Biochimica et Biophysica Acta. Bioenergetics, 2008, 1777 (7-8), pp.919-924. ⟨hal-00324232⟩

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