Two sub-states of the red2 state of methyl-coenzyme M reductase revealed by high-field EPR spectroscopy

Kern, Denise I., Goenrich, Meike, Jaun, Bernhard, Thauer, Rudolf K., Harmer, Jeffrey and Hinderberger, Dariush (2007) Two sub-states of the red2 state of methyl-coenzyme M reductase revealed by high-field EPR spectroscopy. Journal of Biological Inorganic Chemistry, 12 8: 1097-1105. doi:10.1007/s00775-007-0281-3

Author Kern, Denise I.
Goenrich, Meike
Jaun, Bernhard
Thauer, Rudolf K.
Harmer, Jeffrey
Hinderberger, Dariush
Title Two sub-states of the red2 state of methyl-coenzyme M reductase revealed by high-field EPR spectroscopy
Journal name Journal of Biological Inorganic Chemistry   Check publisher's open access policy
ISSN 0949-8257
Publication date 2007-11
Year available 2007
Sub-type Article (original research)
DOI 10.1007/s00775-007-0281-3
Volume 12
Issue 8
Start page 1097
End page 1105
Total pages 9
Place of publication Heidelberg, Germany
Publisher Springer
Collection year 2008
Language eng
Formatted abstract
Methyl-coenzyme M reductase (MCR) catalyzes the formation of methane from methyl-coenzyme M and coenzyme B in methanogenic archaea. The enzyme has two structurally interlinked active sites embedded in an α2β 2γ2 subunit structure. Each active site has the nickel porphyrinoid F430 as a prosthetic group. In the active state, F430 contains the transition metal in the Ni(I) oxidation state. The active enzyme exhibits an axial Ni(I)-based continuous wave (CW) electron paramagnetic resonance (EPR) signal, called red1a in the absence of substrates or red1c in the presence of coenzyme M. Addition of coenzyme B to the MCR-red1 state can partially and reversibly convert it into the MCR-red2 form, which shows a rhombic Ni(I)-based EPR signal (at X-band microwave frequencies of approximately 9.4 GHz). In this report we present evidence from high-field/high-frequency CW EPR spectroscopy (W-band, microwave frequency of approximately 94 GHz) that the red2 state consists of two substates that could not be resolved by EPR spectroscopy at X-band frequencies. At W-band it becomes apparent that upon addition of coenzyme B to MCR in the red1c state, two red2 EPR signals are induced, not one as was previously believed. The first signal is the well-characterized (ortho)rhombic EPR signal, thus far called red2, while the second previously unidentified signal is axial. We have named the two substates MCR-red2r and MCR-red2a after their rhombic and axial signals, respectively.
Keyword Methyl coenzyme M reductase
Nickel enzyme
Methanogenic archaea
Electron paramagnetic resonance spectroscopy
Thermoautotrophicum Strain Marburg
Methanobacterium Thermoautotrophicum
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Centre for Advanced Imaging Publications
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