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Photosystem II in Different Parts of the Thylakoid Membrane: A Functional Comparison between Different Domains

Mamedov, Fikret LU ; Stefansson, Hreinn; Albertsson, Per-Åke LU and Styring, Stenbjörn LU (2000) In Biochemistry 39(34). p.10478-10486
Abstract
The electron transport properties of photosystem II (PSII) from five different domains of the thylakoid membrane were analyzed by flash-induced fluorescence kinetics. These domains are the entire grana, the grana core, the margins from the grana, the stroma lamellae, and the Y100 fraction (which represent more purified stroma lamellae). The two first fractions originate from appressed grana membranes and have PSII with a high proportion of O2-evolving centers (80-90%) and efficient electron transport on the acceptor side. About 30% of the granal PSII centers were found in the margin fraction. Two-thirds of those PSII centers evolve O2, but the electron transfer on the acceptor side is slowed. PSII from the stroma lamellae was less active.... (More)
The electron transport properties of photosystem II (PSII) from five different domains of the thylakoid membrane were analyzed by flash-induced fluorescence kinetics. These domains are the entire grana, the grana core, the margins from the grana, the stroma lamellae, and the Y100 fraction (which represent more purified stroma lamellae). The two first fractions originate from appressed grana membranes and have PSII with a high proportion of O2-evolving centers (80-90%) and efficient electron transport on the acceptor side. About 30% of the granal PSII centers were found in the margin fraction. Two-thirds of those PSII centers evolve O2, but the electron transfer on the acceptor side is slowed. PSII from the stroma lamellae was less active. The fraction containing the entire stroma has only 43% O2-evolving PSII centers and slow electron transfer on the acceptor side. In contrast, PSII centers of the Y100 fraction show no O2 evolution and were unable to reduce QB. Flash-induced fluorescence decay measurements in the presence of DCMU give information about the integrity of the donor side of PSII. We were able to distinguish between PSII centers with a functional Mn cluster and without any Mn cluster, and PSII centers which undergo photoactivation and have a partially assembled Mn cluster. From this analysis, we propose the existence of a PSII activity gradient in the thylakoid membrane. The gradient is directed from the stroma lamellae, where the Mn cluster is absent or inactive, via the margins where photoactivation accelerates, to the grana core domain where PSII is fully photoactivated. The photoactivation process correlates to the PSII diffusion along the membrane and is initiated in the stroma lamellae while the final steps take place in the appressed regions of the grana core. The margin domain is seemingly very important in this process. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biochemistry
volume
39
issue
34
pages
10478 - 10486
publisher
The American Chemical Society
external identifiers
  • scopus:0034730066
ISSN
0006-2960
DOI
10.1021/bi992877k
language
English
LU publication?
yes
id
c37d83db-a138-48f6-9fbb-c80f6fff7480 (old id 125124)
date added to LUP
2007-07-06 11:02:08
date last changed
2017-04-09 03:27:52
@article{c37d83db-a138-48f6-9fbb-c80f6fff7480,
  abstract     = {The electron transport properties of photosystem II (PSII) from five different domains of the thylakoid membrane were analyzed by flash-induced fluorescence kinetics. These domains are the entire grana, the grana core, the margins from the grana, the stroma lamellae, and the Y100 fraction (which represent more purified stroma lamellae). The two first fractions originate from appressed grana membranes and have PSII with a high proportion of O2-evolving centers (80-90%) and efficient electron transport on the acceptor side. About 30% of the granal PSII centers were found in the margin fraction. Two-thirds of those PSII centers evolve O2, but the electron transfer on the acceptor side is slowed. PSII from the stroma lamellae was less active. The fraction containing the entire stroma has only 43% O2-evolving PSII centers and slow electron transfer on the acceptor side. In contrast, PSII centers of the Y100 fraction show no O2 evolution and were unable to reduce QB. Flash-induced fluorescence decay measurements in the presence of DCMU give information about the integrity of the donor side of PSII. We were able to distinguish between PSII centers with a functional Mn cluster and without any Mn cluster, and PSII centers which undergo photoactivation and have a partially assembled Mn cluster. From this analysis, we propose the existence of a PSII activity gradient in the thylakoid membrane. The gradient is directed from the stroma lamellae, where the Mn cluster is absent or inactive, via the margins where photoactivation accelerates, to the grana core domain where PSII is fully photoactivated. The photoactivation process correlates to the PSII diffusion along the membrane and is initiated in the stroma lamellae while the final steps take place in the appressed regions of the grana core. The margin domain is seemingly very important in this process.},
  author       = {Mamedov, Fikret and Stefansson, Hreinn and Albertsson, Per-Åke and Styring, Stenbjörn},
  issn         = {0006-2960},
  language     = {eng},
  number       = {34},
  pages        = {10478--10486},
  publisher    = {The American Chemical Society},
  series       = {Biochemistry},
  title        = {Photosystem II in Different Parts of the Thylakoid Membrane: A Functional Comparison between Different Domains},
  url          = {http://dx.doi.org/10.1021/bi992877k},
  volume       = {39},
  year         = {2000},
}