Numerical Simulation of One- and Two-Dimensional ESEEM Experiments

Mádi, Z. L.; Doorslaer, Sabine Van; Schweiger, Arthur

doi:10.1006/jmre.2001.2479

Cited by 70 publications

(87 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…All measurements used an eightstep phase cycle to remove unwanted echoes. The fieldswept EPR and Davies ENDOR spectra were simulated with the MATLAB-based program package EasySpin [39], and the HYSCORE spectra with a program written in-house [40].…”

Section: Purification Of Active Mcrmentioning

confidence: 99%

Coordination and binding geometry of methyl-coenzyme M in the red1m state of methyl-coenzyme M reductase

et al. 2008

View full text Add to dashboard Cite

Methane formation in methanogenic Archaea is catalyzed by methyl-coenzyme M reductase (MCR) and takes place via the reduction of methyl-coenzyme M (CH 3 -S-CoM) with coenzyme B (HS-CoB) to methane and the heterodisulfide CoM-S-S-CoB. MCR harbors the nickel porphyrinoid coenzyme F 430 as a prosthetic group, which has to be in the Ni(I) oxidation state for the enzyme to be active. To date no intermediates in the catalytic cycle of MCR red1 (red for reduced Ni) have been identified. Here, we report a detailed characterization of MCR red1m (''m'' for methyl-coenzyme M), which is the complex of MCR red1a (''a'' for absence of substrate) with CH 3 -S-CoM. Using continuous-wave and pulse electron paramagnetic resonance spectroscopy in combination with selective isotope labeling ( 13 C and 2 H) of CH 3 -S-CoM, it is shown that CH 3 -S-CoM binds in the active site of MCR such that its thioether sulfur is weakly coordinated to the Ni(I) of F 430 . The complex is stable until the addition of the second substrate, HS-CoB. Results from EPR spectroscopy, along with quantum mechanical calculations, are used to characterize the electronic and geometric structure of this complex, which can be regarded as the first intermediate in the catalytic mechanism.

show abstract

Section: Purification Of Active Mcrmentioning

confidence: 99%

Coordination and binding geometry of methyl-coenzyme M in the red1m state of methyl-coenzyme M reductase

et al. 2008

View full text Add to dashboard Cite

show abstract

“…The simulations of the HYSCORE spectra were done using different approaches (frequency-domain simulations by EasySpin [20] and time-domain simulations by a gamma-based program [23], both developed at ETH Zu¡ In order to check the validity of the S :fr= 1/2 description for the Fe(III) system, different Matlabbased codes were written allowing for a computation of the nuclear frequencies in case of a full S = 5/2 description and in case of the 5~er= 1/2 description in different orders of approximation.…”

Section: Data Manipulation and Simulations Of Eseem Spectramentioning

confidence: 99%

Studying high-spin ferric heme proteins by pulsed EPR spectroscopy: Analysis of the ferric form of the E7Q mutant of human neuroglobin

et al. 2007

Self Cite

View full text Add to dashboard Cite

In this work, the high-spin ferric form of the E7Q mutant of human neuroglobin (E7Q-NGB) is studied by X-band continuous-wave electron paramagnetic resonance (CW EPR) and hyperŸ237 sublevel correlation (HYSCORE) spectroscopy. It is shown that the use of matched pulses in the HYSCORE experiment is essential to observe the nitrogen speetral contributions. The validity of approximating the high-spin Fe(IID system (S = 5/2) as an effective S = 1/2 system is tested and the consequences for the HYSCORE simulations are highlighted. Comparative HYSCORE experiments combined with deuterium exchange experiments for aquometmyoglobin and fer¡ E7Q-NGB clearly show that the heme iron of the latter protein is pentacoordinated, tacking the distal water. Furthermore, CW EPR experiments show that, at high pH, the E10K residue is coordinating to the heme iron in this globin. These observations ate corroborated by resonance Raman experiments and could also be reproduced for other E7 mutants of human and mouse neuroglobin. Finally, the proton and nitrogen hyperfine and nuclear quadrupole parameters obtained for ferric E7Q-NGB are discussed in detail.

show abstract

“…For the HYSCORE spectra, the absolute value spectra were calculated after 2D Fourier transformation. The HYSCORE spectra were simulated using a program developed at the ETH Zurich ( [31], time-domain simulation) and EasySpin ( [26], frequency-domain simulation). However, the appearance of the HS signal was found to strongly depend on the protein batch.…”

Section: Continuous-wave Electron Paramagnetic Resonance (Cw Epr) Cwmentioning

confidence: 99%

Probing the heme-pocket structure of the paramagnetic forms of cytoglobin and a distal histidine mutant using electron paramagnetic resonance

et al. 2007

View full text Add to dashboard Cite

Numerical Simulation of One- and Two-Dimensional ESEEM Experiments

Cited by 70 publications

References 46 publications

Coordination and binding geometry of methyl-coenzyme M in the red1m state of methyl-coenzyme M reductase

Coordination and binding geometry of methyl-coenzyme M in the red1m state of methyl-coenzyme M reductase

Studying high-spin ferric heme proteins by pulsed EPR spectroscopy: Analysis of the ferric form of the E7Q mutant of human neuroglobin

Probing the heme-pocket structure of the paramagnetic forms of cytoglobin and a distal histidine mutant using electron paramagnetic resonance

Contact Info

Product

Resources

About