TY - JOUR
T1 - The effect of temperature on the formation and decay of the multiline EPR signal species associated with photosynthetic oxygen evolution
AU - Brudvig, Gary W.
AU - Casey, John L.
AU - Sauer, Kenneth
N1 - Funding Information:
We thank David B. Goodin for insightful discussions. This work was supported by the Office of Energy Research, Office of Basic Energy Sciences, Biological Energy Research Division of the U.S. Department of Energy, under Contract DE-AC03-76SF00098, and National Science Foundation Grant PCM 78-12121. G.W.B. Acknowledges support from the Miller Institute for Basic Research in Science of the University of California, Berkeley.
PY - 1983/6/30
Y1 - 1983/6/30
N2 - We have investigated the effects of temperature on the formation and decay of the light-induced multiline EPR signal species associated with photosynthetic oxygen evolution (Dismukes, G.C. and Siderer, Y. (1980) FEBS Lett. 121, 78-80). (1) The decay rate following illumination is temperature dependent: at 295 K the half-time of decay is about 40 s, at 253 K the half-time is approx. 40 min. (2) A single intense flash of light becomes progressively less effective in generating the multiline signal below about 240 K. (3) Continuous illumination is capable of generating the signal down to almost 160 K. (4) Continuous illumination after a preilluminating flash generates less signal above 200 K than at lower temperatures. Our results support the conclusion of Dismukes and Siderer that the S2 state gives rise to this multiline signal; we find that the S1 state can be fully advanced to the S2 state at temperatures as low as 160 K. The S2 state is capable of further advancement at temperatures above about 210 K, but not below that temperature.
AB - We have investigated the effects of temperature on the formation and decay of the light-induced multiline EPR signal species associated with photosynthetic oxygen evolution (Dismukes, G.C. and Siderer, Y. (1980) FEBS Lett. 121, 78-80). (1) The decay rate following illumination is temperature dependent: at 295 K the half-time of decay is about 40 s, at 253 K the half-time is approx. 40 min. (2) A single intense flash of light becomes progressively less effective in generating the multiline signal below about 240 K. (3) Continuous illumination is capable of generating the signal down to almost 160 K. (4) Continuous illumination after a preilluminating flash generates less signal above 200 K than at lower temperatures. Our results support the conclusion of Dismukes and Siderer that the S2 state gives rise to this multiline signal; we find that the S1 state can be fully advanced to the S2 state at temperatures as low as 160 K. The S2 state is capable of further advancement at temperatures above about 210 K, but not below that temperature.
KW - (Spinach chloroplast)
KW - ESR
KW - Oxygen evolution
KW - Photosynthesis
KW - Temperature effect
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U2 - 10.1016/0005-2728(83)90042-7
DO - 10.1016/0005-2728(83)90042-7
M3 - Article
AN - SCOPUS:0000269978
VL - 723
SP - 366
EP - 371
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 3
ER -