Proton-transfer dynamics in the activation of cytochrome P450eryF.
Molecular dynamics simulations are combined with quantum chemistry calculations of instantaneous proton-transfer energy profiles to investigate proton-transfer events in the transient pathway of cytochrome P450eryF (6-deoxyerythronolide B hydroxylase; CYP107A1), from the oxyferrous species to the catalytically active ferryl oxygen species (compound I). This reaction is one of the most fundamental unresolved aspects in the mechanism of oxidation that is common to all cytochrome P450s. We find that this process involves an ultrafast proton transfer from the crystallographic water molecule W519 to the distal oxygen bound to the heme group, and a subsequent proton-transfer event from W564 to W519. Both proton-transfer events are found to be endothermic in the oxyferrous state, suggesting that the oxyferrous reduction is mechanistically linked to the proton-transfer dynamics. These findings indicate that the hydrogen bond network, proximate to the O(2)-binding cleft, plays a crucial functional role in the enzymatic activation of P450s. Our results are consistent with the effect of mutations on the enzymatic efficacy.
Guallar
Victor
V
Department of Chemistry, University of California, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Harris
Danni L
DL
Batista
Victor S
VS
Miller
William H
WH
D001426:Bacterial Proteins; D003198:Computer Simulation; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism*; D004789:Enzyme Activation; D006899:Mixed Function Oxygenases / Q000737:chemistry* / Q000378:metabolism*; D008956:Models, Chemical; D008958:Models, Molecular; D011522:Protons; D013816:Thermodynamics
D001426:Bacterial Proteins; D011522:Protons; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; C054444:eryF protein, Saccharopolyspora erythraea