Mechanistic Studies of Reactions of Peroxodiiron(III) Intermediates in T201 Variants of Toluene/o-Xylene Monooxygenase Hydroxylase
Author(s)
Lippard, Stephen J.; Song, Woon Ju
DownloadLippard_Mechanistic Studies.pdf (1.073Mb)
PUBLISHER_POLICY
Publisher Policy
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Terms of use
Metadata
Show full item recordAbstract
Site-directed mutagenesis studies of a strictly conserved T201 residue in the active site of toluene/o-xylene monooxygenase hydroxylase (ToMOH) revealed that a single mutation can facilitate kinetic isolation of two distinctive peroxodiiron(III) species, designated T201peroxo and ToMOHperoxo, during dioxygen activation. Previously, we characterized both oxygenated intermediates by UV–vis and Mössbauer spectroscopy, proposed structures from DFT and QM/MM computational studies, and elucidated chemical steps involved in dioxygen activation through the kinetic studies of T201peroxo formation. In this study, we investigate the kinetics of T201peroxo decay to explore the reaction mechanism of the oxygenated intermediates following O2 activation. The decay rates of T201peroxo were monitored in the absence and presence of external (phenol) or internal (tryptophan residue in an I100W variant) substrates under pre-steady-state conditions. Three possible reaction models for the formation and decay of T201peroxo were evaluated, and the results demonstrate that this species is on the pathway of arene oxidation and appears to be in equilibrium with ToMOHperoxo.
Date issued
2011-05Department
Massachusetts Institute of Technology. Department of ChemistryJournal
Biochemistry
Publisher
American Chemical Society
Citation
Lippard, Stephen J., and Woon Ju Song. "Mechanistic Studies of Reactions of Peroxodiiron(III) Intermediates in T201 Variants of Toluene/o-Xylene Monooxygenase Hydroxylase." Biochemistry 50 (2011): 5391-5399. http://dx.doi.org/10.1021/bi200340f
Version: Author's final manuscript
ISSN
0006-2960