High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II

K. V. Lakshmi, Michael J. Reifler, Gary W Brudvig, Oleg G. Poluektov, Arlene M. Wagner, Marion C. Thurnauer

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

In photosystem II (PS II), chlorophyll, β-carotene, and cytochrome 0559 are alternate electron donors that may be involved in a photoprotection mechanism. The present study describes the use of high-field EPR spectroscopy to characterize the low-temperature photooxidation of Chl z- and Car cofactors in PS II. The EPR signals of the individual species, previously not resolved at X-band frequency (9 GHz), are resolved at higher D-band frequency (130 GHz) in deuterated Synechococcus lividus PS II. Deuteration of PS II results in significant narrowing of the EPR lines, yielding well-resolved EPR spectra of the Car + and Chl z + radicals at 130 GHz. The g tensors of the individual species were determined by EPR spectral simulations. The g tensor determined for the Car + radical (g xx = 2.00335, g yy = 2.00251, g zz = 2.00227) is similar to that previously observed for a canthaxanthin cation radical but with a slightly rhombic tensor. The Chl z + g tensor (g xx= 2.00312, g yy = 2.00263, g zz = 2.00202) is similar to that of a chlorophyll a cation radical. This study shows that both the carotenoid and chlorophyll radicals are generated in PS II by illumination at temperatures from 6 to 190 K and that there is no interconversion of Car + and Chl z + radicals upon dark annealing at temperatures up to 160 K. This study also establishes the feasibility of using deuteration and high-field EPR to resolve previously unresolvable cofactor signals in PS II.

Original languageEnglish
Pages (from-to)10447-10448
Number of pages2
JournalJournal of Physical Chemistry B
Volume104
Issue number45
Publication statusPublished - Nov 16 2000

Fingerprint

carotenoids
Photosystem II Protein Complex
chlorophylls
Chlorophyll
Carotenoids
Paramagnetic resonance
Cations
Positive ions
cations
Tensors
Railroad cars
tensors
Frequency bands
Canthaxanthin
carotene
Photooxidation
photooxidation
cytochromes
Cytochromes
superhigh frequencies

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Engineering(all)

Cite this

Lakshmi, K. V., Reifler, M. J., Brudvig, G. W., Poluektov, O. G., Wagner, A. M., & Thurnauer, M. C. (2000). High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II. Journal of Physical Chemistry B, 104(45), 10447-10448.

High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II. / Lakshmi, K. V.; Reifler, Michael J.; Brudvig, Gary W; Poluektov, Oleg G.; Wagner, Arlene M.; Thurnauer, Marion C.

In: Journal of Physical Chemistry B, Vol. 104, No. 45, 16.11.2000, p. 10447-10448.

Research output: Contribution to journalArticle

Lakshmi, KV, Reifler, MJ, Brudvig, GW, Poluektov, OG, Wagner, AM & Thurnauer, MC 2000, 'High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II', Journal of Physical Chemistry B, vol. 104, no. 45, pp. 10447-10448.
Lakshmi KV, Reifler MJ, Brudvig GW, Poluektov OG, Wagner AM, Thurnauer MC. High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II. Journal of Physical Chemistry B. 2000 Nov 16;104(45):10447-10448.
Lakshmi, K. V. ; Reifler, Michael J. ; Brudvig, Gary W ; Poluektov, Oleg G. ; Wagner, Arlene M. ; Thurnauer, Marion C. / High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II. In: Journal of Physical Chemistry B. 2000 ; Vol. 104, No. 45. pp. 10447-10448.
@article{64b34271a6cb48ee9bcad9de71177fb2,
title = "High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II",
abstract = "In photosystem II (PS II), chlorophyll, β-carotene, and cytochrome 0559 are alternate electron donors that may be involved in a photoprotection mechanism. The present study describes the use of high-field EPR spectroscopy to characterize the low-temperature photooxidation of Chl z- and Car cofactors in PS II. The EPR signals of the individual species, previously not resolved at X-band frequency (9 GHz), are resolved at higher D-band frequency (130 GHz) in deuterated Synechococcus lividus PS II. Deuteration of PS II results in significant narrowing of the EPR lines, yielding well-resolved EPR spectra of the Car + and Chl z + radicals at 130 GHz. The g tensors of the individual species were determined by EPR spectral simulations. The g tensor determined for the Car + radical (g xx = 2.00335, g yy = 2.00251, g zz = 2.00227) is similar to that previously observed for a canthaxanthin cation radical but with a slightly rhombic tensor. The Chl z + g tensor (g xx= 2.00312, g yy = 2.00263, g zz = 2.00202) is similar to that of a chlorophyll a cation radical. This study shows that both the carotenoid and chlorophyll radicals are generated in PS II by illumination at temperatures from 6 to 190 K and that there is no interconversion of Car + and Chl z + radicals upon dark annealing at temperatures up to 160 K. This study also establishes the feasibility of using deuteration and high-field EPR to resolve previously unresolvable cofactor signals in PS II.",
author = "Lakshmi, {K. V.} and Reifler, {Michael J.} and Brudvig, {Gary W} and Poluektov, {Oleg G.} and Wagner, {Arlene M.} and Thurnauer, {Marion C.}",
year = "2000",
month = "11",
day = "16",
language = "English",
volume = "104",
pages = "10447--10448",
journal = "Journal of Physical Chemistry B Materials",
issn = "1520-6106",
publisher = "American Chemical Society",
number = "45",

}

TY - JOUR

T1 - High-field EPR study of carotenoid and chlorophyll cation radicals in photosystem II

AU - Lakshmi, K. V.

AU - Reifler, Michael J.

AU - Brudvig, Gary W

AU - Poluektov, Oleg G.

AU - Wagner, Arlene M.

AU - Thurnauer, Marion C.

PY - 2000/11/16

Y1 - 2000/11/16

N2 - In photosystem II (PS II), chlorophyll, β-carotene, and cytochrome 0559 are alternate electron donors that may be involved in a photoprotection mechanism. The present study describes the use of high-field EPR spectroscopy to characterize the low-temperature photooxidation of Chl z- and Car cofactors in PS II. The EPR signals of the individual species, previously not resolved at X-band frequency (9 GHz), are resolved at higher D-band frequency (130 GHz) in deuterated Synechococcus lividus PS II. Deuteration of PS II results in significant narrowing of the EPR lines, yielding well-resolved EPR spectra of the Car + and Chl z + radicals at 130 GHz. The g tensors of the individual species were determined by EPR spectral simulations. The g tensor determined for the Car + radical (g xx = 2.00335, g yy = 2.00251, g zz = 2.00227) is similar to that previously observed for a canthaxanthin cation radical but with a slightly rhombic tensor. The Chl z + g tensor (g xx= 2.00312, g yy = 2.00263, g zz = 2.00202) is similar to that of a chlorophyll a cation radical. This study shows that both the carotenoid and chlorophyll radicals are generated in PS II by illumination at temperatures from 6 to 190 K and that there is no interconversion of Car + and Chl z + radicals upon dark annealing at temperatures up to 160 K. This study also establishes the feasibility of using deuteration and high-field EPR to resolve previously unresolvable cofactor signals in PS II.

AB - In photosystem II (PS II), chlorophyll, β-carotene, and cytochrome 0559 are alternate electron donors that may be involved in a photoprotection mechanism. The present study describes the use of high-field EPR spectroscopy to characterize the low-temperature photooxidation of Chl z- and Car cofactors in PS II. The EPR signals of the individual species, previously not resolved at X-band frequency (9 GHz), are resolved at higher D-band frequency (130 GHz) in deuterated Synechococcus lividus PS II. Deuteration of PS II results in significant narrowing of the EPR lines, yielding well-resolved EPR spectra of the Car + and Chl z + radicals at 130 GHz. The g tensors of the individual species were determined by EPR spectral simulations. The g tensor determined for the Car + radical (g xx = 2.00335, g yy = 2.00251, g zz = 2.00227) is similar to that previously observed for a canthaxanthin cation radical but with a slightly rhombic tensor. The Chl z + g tensor (g xx= 2.00312, g yy = 2.00263, g zz = 2.00202) is similar to that of a chlorophyll a cation radical. This study shows that both the carotenoid and chlorophyll radicals are generated in PS II by illumination at temperatures from 6 to 190 K and that there is no interconversion of Car + and Chl z + radicals upon dark annealing at temperatures up to 160 K. This study also establishes the feasibility of using deuteration and high-field EPR to resolve previously unresolvable cofactor signals in PS II.

UR - http://www.scopus.com/inward/record.url?scp=0034322756&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0034322756&partnerID=8YFLogxK

M3 - Article

VL - 104

SP - 10447

EP - 10448

JO - Journal of Physical Chemistry B Materials

JF - Journal of Physical Chemistry B Materials

SN - 1520-6106

IS - 45

ER -