TY - JOUR
T1 - An ESEEM study of the oxidized electron donor of plant photosystem II
T2 - Evidence that D is a neutral tyrosine radical
AU - Evelo, R. G.
AU - Hoff, A. J.
AU - Dikanov, S. A.
AU - Tyryshkin, A. M.
N1 - Funding Information:
We are indebted to Dr. R. de Beer for making the Fourier and cosine transformation programs available to us, to Ms. M.C. Nieveen for her skilful preparation of the PS II-enriched particles and to Mrs. M.L. van der Erf and Mr. A.H.M. de Wit for culturing the algae. The oxygen evolution measurements were performed by P.J. van Leeuwen. This work was supported by the Netherlands Foundation for Chemical Research (SON), financed by the Netherlands Organization for Scientific Research (NWO). SAD thanks NW0 for supporting his sojourn at the University of Leiden, and the Department of Biophysics for its hospitality.
PY - 1989/9/29
Y1 - 1989/9/29
N2 - Electron spin-echo envelope modulation (ESEEM) has been performed on the tyrosyl radical D{A figure is presented} in photosystem II of plants and algae. This radical was investigated in PS II-enriched subchloroplast particles, and in perdeuterated and 15N-substituted Chlorella vulgaris algae. From the ESEEM analysis in the time and frequency domain, two proton hyperfine interactions were determined. One of these protons has hyperfine parameters aiso=27.2 MHz, T11=-3.1 MHz and T22/T11=0.5. The second proton, which is easily exchangeable by deuterium, has parameters aiso=±1.6 MHz, T11=∓8.4 MHz and T22/T11=1. The hyperfine parameters of the first proton are characteristic of a β-methylene proton, whereas those of the second indicate that it is a proton hydrogen bonded to the tyrosyl oxygen. We conclude that the oxidized tyrosyl donor is a neutral hydrogen-bonded radical.
AB - Electron spin-echo envelope modulation (ESEEM) has been performed on the tyrosyl radical D{A figure is presented} in photosystem II of plants and algae. This radical was investigated in PS II-enriched subchloroplast particles, and in perdeuterated and 15N-substituted Chlorella vulgaris algae. From the ESEEM analysis in the time and frequency domain, two proton hyperfine interactions were determined. One of these protons has hyperfine parameters aiso=27.2 MHz, T11=-3.1 MHz and T22/T11=0.5. The second proton, which is easily exchangeable by deuterium, has parameters aiso=±1.6 MHz, T11=∓8.4 MHz and T22/T11=1. The hyperfine parameters of the first proton are characteristic of a β-methylene proton, whereas those of the second indicate that it is a proton hydrogen bonded to the tyrosyl oxygen. We conclude that the oxidized tyrosyl donor is a neutral hydrogen-bonded radical.
UR - http://www.scopus.com/inward/record.url?scp=0000180673&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0000180673&partnerID=8YFLogxK
U2 - 10.1016/0009-2614(89)87024-1
DO - 10.1016/0009-2614(89)87024-1
M3 - Article
AN - SCOPUS:0000180673
SN - 0009-2614
VL - 161
SP - 479
EP - 484
JO - Chemical Physics Letters
JF - Chemical Physics Letters
IS - 6
ER -