Abstract
Pulse electron paramagnetic resonance (EPR) spectroscopy is employed at two very different excitation frequencies, 9.77 and 30.67 GHz, in the study of the nitrogen coordination environment of the Mn(III)Mn(IV) state of the dimanganese-containing catalases from Lactobacillus plantaram and Thermus thermophilus. Consistent with previous studies, the lower-frequency results reveal one unique histidine nitrogen-Mn cluster interaction. For the first time, a second, more strongly hyperfine-coupled 14N atom is unambiguously observed through the use of higher frequency/higher field EPR spectroscopy. The low excitation frequency spectral features are rationalized as arising from the interaction of a histidine nitrogen that is bound to the Mn(IV) ion, and the higher excitation frequency features are attributed to the histidine nitrogen bound to the Mn(III) ion. These results allow for the computation of intrinsic hyperfine coupling constants, which range from 2.2 to 2.9 MHz, for sp 2-hybridized nitrogens coordinating equatorially to high-valence Mn ions. The relevance of these findings is discussed in the context of recent results from analogous higher frequency EPR studies of the Mn cluster in photosystem II and other exchange-coupled, transition metal-containing systems.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 14178-14188 |
| Number of pages | 11 |
| Journal | Journal of Physical Chemistry B |
| Volume | 114 |
| Issue number | 45 |
| DOIs | |
| State | Published - Dec 8 2010 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Materials Chemistry
- Surfaces, Coatings and Films
Cite this
Multifrequency EPR studies of manganese catalases provide a complete description of proteinaceous nitrogen coordination. / Stich, Troy A.; Whittaker, James; David Britt, R.
In: Journal of Physical Chemistry B, Vol. 114, No. 45, 08.12.2010, p. 14178-14188.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Multifrequency EPR studies of manganese catalases provide a complete description of proteinaceous nitrogen coordination
AU - Stich, Troy A.
AU - Whittaker, James
AU - David Britt, R.
PY - 2010/12/8
Y1 - 2010/12/8
N2 - Pulse electron paramagnetic resonance (EPR) spectroscopy is employed at two very different excitation frequencies, 9.77 and 30.67 GHz, in the study of the nitrogen coordination environment of the Mn(III)Mn(IV) state of the dimanganese-containing catalases from Lactobacillus plantaram and Thermus thermophilus. Consistent with previous studies, the lower-frequency results reveal one unique histidine nitrogen-Mn cluster interaction. For the first time, a second, more strongly hyperfine-coupled 14N atom is unambiguously observed through the use of higher frequency/higher field EPR spectroscopy. The low excitation frequency spectral features are rationalized as arising from the interaction of a histidine nitrogen that is bound to the Mn(IV) ion, and the higher excitation frequency features are attributed to the histidine nitrogen bound to the Mn(III) ion. These results allow for the computation of intrinsic hyperfine coupling constants, which range from 2.2 to 2.9 MHz, for sp 2-hybridized nitrogens coordinating equatorially to high-valence Mn ions. The relevance of these findings is discussed in the context of recent results from analogous higher frequency EPR studies of the Mn cluster in photosystem II and other exchange-coupled, transition metal-containing systems.
AB - Pulse electron paramagnetic resonance (EPR) spectroscopy is employed at two very different excitation frequencies, 9.77 and 30.67 GHz, in the study of the nitrogen coordination environment of the Mn(III)Mn(IV) state of the dimanganese-containing catalases from Lactobacillus plantaram and Thermus thermophilus. Consistent with previous studies, the lower-frequency results reveal one unique histidine nitrogen-Mn cluster interaction. For the first time, a second, more strongly hyperfine-coupled 14N atom is unambiguously observed through the use of higher frequency/higher field EPR spectroscopy. The low excitation frequency spectral features are rationalized as arising from the interaction of a histidine nitrogen that is bound to the Mn(IV) ion, and the higher excitation frequency features are attributed to the histidine nitrogen bound to the Mn(III) ion. These results allow for the computation of intrinsic hyperfine coupling constants, which range from 2.2 to 2.9 MHz, for sp 2-hybridized nitrogens coordinating equatorially to high-valence Mn ions. The relevance of these findings is discussed in the context of recent results from analogous higher frequency EPR studies of the Mn cluster in photosystem II and other exchange-coupled, transition metal-containing systems.
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U2 - 10.1021/jp908064y
DO - 10.1021/jp908064y
M3 - Article
VL - 114
SP - 14178
EP - 14188
JO - Journal of Physical Chemistry B Materials
JF - Journal of Physical Chemistry B Materials
SN - 1520-6106
IS - 45
ER -