One- and Two-Dimensional Electron Spin Echo Envelope Modulation Study of the Intermediate Electron Acceptor Pheophytin in14N- and15N-Labeled Photosystem II

1997 ◽  
Vol 119 (19) ◽  
pp. 4471-4480 ◽  
Author(s):  
Yiannis Deligiannakis ◽  
A. William Rutherford
Keyword(s):  
Photosystem Ii ◽  
Electron Spin ◽  
Electron Acceptor ◽  
Spin Echo ◽  
Electron Spin Echo ◽  
Two Dimensional ◽  
Dimensional Electron ◽  
Envelope Modulation

An electron spin echo envelope modulation study of the primary acceptor quinone in Zn‐substituted plant photosystem II

1995 ◽  
Vol 102 (14) ◽  
pp. 5583-5588 ◽  
Author(s):  
Andrei V. Astashkin ◽  
Asako Kawamori ◽  
Yoshio Kodera ◽  
Shigeki Kuroiwa ◽  
Kozo Akabori
Keyword(s):  
Photosystem Ii ◽  
Electron Spin ◽  
Spin Echo ◽  
Electron Spin Echo ◽  
Primary Acceptor ◽  
Envelope Modulation

scholarly journals Multifrequency electron spin-echo envelope modulation studies of nitrogen ligation to the manganese cluster of photosystem II

2007 ◽  
Vol 363 (1494) ◽  
pp. 1157-1166 ◽  
Author(s):  
Gregory J Yeagle ◽  
M. Lane Gilchrist ◽  
Lee M Walker ◽  
Richard J Debus ◽  
R. David Britt
Keyword(s):  
Photosystem Ii ◽  
Electron Spin ◽  
Spin Echo ◽  
Electron Spin Echo ◽  
Intermediate Frequency ◽  
Low Frequencies ◽  
Pulsed Epr ◽  
Depth Analysis ◽  
Mn Cluster ◽  
Envelope Modulation

The CalEPR Center at UC-Davis ( http://brittepr.ucdavis.edu ) is equipped with five research grade electron paramagnetic resonance (EPR) instruments operating at various excitation frequencies between 8 and 130 GHz. Of particular note for this RSC meeting are two pulsed EPR spectrometers working at the intermediate microwave frequencies of 31 and 35 GHz. Previous lower frequency electron spin-echo envelope modulation (ESEEM) studies indicated that histidine nitrogen is electronically coupled to the Mn cluster in the S 2 state of photosystem II (PSII). However, the amplitude and resolution of the spectra were relatively poor at these low frequencies, precluding any in-depth analysis of the electronic structure properties of this closely associated nitrogen nucleus. With the intermediate frequency instruments, we are much closer to the ‘exact cancellation’ limit, which optimizes ESEEM spectra for hyperfine-coupled nuclei such as 14 N and 15 N. Herein, we report the results from ESEEM studies of both 14 N- and 15 N-labelled PSII at these two frequencies. Spectral simulations were constrained by both isotope datasets at both frequencies, with a focus on high-resolution spectral examination of the histidine ligation to the Mn cluster in the S 2 state.

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