Progress in Characterization of the Photosystem II Oxygen Evolving Complex Using Advanced EPR Methods

R. David Britt; Dee Ann Force; Kristy A. Campbell; David W. Randall; Lane M. Gilchrist; Keri L. Clemens; David M. Gingell; Jeffrey M. Peloquin; Donna P. Pham; Richard J. Debus

Progress in Characterization of the Photosystem II Oxygen Evolving Complex Using Advanced EPR Methods

R. David Britt, Dee Ann Force, Kristy A. Campbell, David W. Randall, Lane M. Gilchrist, Keri L. Clemens, David M. Gingell, Jeffrey M. Peloquin, Donna P. Pham, Richard J. Debus

Electrical Engineering Department

Research output: Contribution to journal › Article › peer-review

6 Scopus citations

Abstract

We have utilized both continuous wave (CW) EPR and pulsed EPR spectroscopies to characterize the structure and function of the oxygen-evolving complex (OEC) of Photosystem II (PSII). Parallel polarization CW EPR spectroscopy of the dark-stable S₁-state of the OEC in PSII particles isolated from the cyanobacterium Synechocystis sp. PCC 6803 reveals a ΔMs = 0 signal, centered at a g-value of approximately 12, with 18 or more well-resolved ⁵⁵Mn hyperfine lines. This signal provides direct evidence for the presence of a tri- or tetranuclear coupled Mn cluster in the S₁-state. Electron spin echo (ESE) envelope modulation (ESEEM) and ESE-ENDOR experiments indicate that substrate water and small alcohol derived ligands are bound to the Mn cluster in the S₂-state of the cycle. Progress in modeling the magnetic interaction between the photo-oxidized Y^•_Z tyrosine and the Mn cluster is described, along with new pulsed EPR evidence supporting recent models that suggest Y^•_Z is directly involved in the water oxidation chemistry.

Original language	English
Pages (from-to)	272-285
Number of pages	14
Journal	ACS Symposium Series
Volume	692
State	Published - 1998

Cite this

@article{8f0c306dd2844cc083d7bf013f3a55ea,

title = "Progress in Characterization of the Photosystem II Oxygen Evolving Complex Using Advanced EPR Methods",

abstract = "We have utilized both continuous wave (CW) EPR and pulsed EPR spectroscopies to characterize the structure and function of the oxygen-evolving complex (OEC) of Photosystem II (PSII). Parallel polarization CW EPR spectroscopy of the dark-stable S1-state of the OEC in PSII particles isolated from the cyanobacterium Synechocystis sp. PCC 6803 reveals a ΔMs = 0 signal, centered at a g-value of approximately 12, with 18 or more well-resolved 55Mn hyperfine lines. This signal provides direct evidence for the presence of a tri- or tetranuclear coupled Mn cluster in the S1-state. Electron spin echo (ESE) envelope modulation (ESEEM) and ESE-ENDOR experiments indicate that substrate water and small alcohol derived ligands are bound to the Mn cluster in the S2-state of the cycle. Progress in modeling the magnetic interaction between the photo-oxidized Y•Z tyrosine and the Mn cluster is described, along with new pulsed EPR evidence supporting recent models that suggest Y•Z is directly involved in the water oxidation chemistry.",

author = "Britt, {R. David} and Force, {Dee Ann} and Campbell, {Kristy A.} and Randall, {David W.} and Gilchrist, {Lane M.} and Clemens, {Keri L.} and Gingell, {David M.} and Peloquin, {Jeffrey M.} and Pham, {Donna P.} and Debus, {Richard J.}",

year = "1998",

language = "English",

volume = "692",

pages = "272--285",

}

TY - JOUR

T1 - Progress in Characterization of the Photosystem II Oxygen Evolving Complex Using Advanced EPR Methods

AU - Britt, R. David

AU - Force, Dee Ann

AU - Campbell, Kristy A.

AU - Randall, David W.

AU - Gilchrist, Lane M.

AU - Clemens, Keri L.

AU - Gingell, David M.

AU - Peloquin, Jeffrey M.

AU - Pham, Donna P.

AU - Debus, Richard J.

PY - 1998

Y1 - 1998

N2 - We have utilized both continuous wave (CW) EPR and pulsed EPR spectroscopies to characterize the structure and function of the oxygen-evolving complex (OEC) of Photosystem II (PSII). Parallel polarization CW EPR spectroscopy of the dark-stable S1-state of the OEC in PSII particles isolated from the cyanobacterium Synechocystis sp. PCC 6803 reveals a ΔMs = 0 signal, centered at a g-value of approximately 12, with 18 or more well-resolved 55Mn hyperfine lines. This signal provides direct evidence for the presence of a tri- or tetranuclear coupled Mn cluster in the S1-state. Electron spin echo (ESE) envelope modulation (ESEEM) and ESE-ENDOR experiments indicate that substrate water and small alcohol derived ligands are bound to the Mn cluster in the S2-state of the cycle. Progress in modeling the magnetic interaction between the photo-oxidized Y•Z tyrosine and the Mn cluster is described, along with new pulsed EPR evidence supporting recent models that suggest Y•Z is directly involved in the water oxidation chemistry.

AB - We have utilized both continuous wave (CW) EPR and pulsed EPR spectroscopies to characterize the structure and function of the oxygen-evolving complex (OEC) of Photosystem II (PSII). Parallel polarization CW EPR spectroscopy of the dark-stable S1-state of the OEC in PSII particles isolated from the cyanobacterium Synechocystis sp. PCC 6803 reveals a ΔMs = 0 signal, centered at a g-value of approximately 12, with 18 or more well-resolved 55Mn hyperfine lines. This signal provides direct evidence for the presence of a tri- or tetranuclear coupled Mn cluster in the S1-state. Electron spin echo (ESE) envelope modulation (ESEEM) and ESE-ENDOR experiments indicate that substrate water and small alcohol derived ligands are bound to the Mn cluster in the S2-state of the cycle. Progress in modeling the magnetic interaction between the photo-oxidized Y•Z tyrosine and the Mn cluster is described, along with new pulsed EPR evidence supporting recent models that suggest Y•Z is directly involved in the water oxidation chemistry.

UR - http://www.scopus.com/inward/record.url?scp=0347652981&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0347652981

SN - 0097-6156

VL - 692

SP - 272

EP - 285

JO - ACS Symposium Series

JF - ACS Symposium Series

ER -

Progress in Characterization of the Photosystem II Oxygen Evolving Complex Using Advanced EPR Methods

Abstract

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