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Photoactivation and Photoinhibition Are Competing in a Mutant of Chlamydomonas reinhardtii Lacking the 23-kDa Extrinsic Subunit of Photosystem II

Rova, E Maria; Mc Ewen, Birgitta; Fredriksson, Per-Olof and Styring, Stenbjörn LU (1996) In Journal of Biological Chemistry 271(46). p.28918-28924
Abstract
The process of photoactivation has been studied in dark grown cells of Chlamydomonas reinhardtii. A mutant, FUD 39, lacking the Cl-concentrating 23-kDa psbP protein of photosystem II was found to have a decreased capability to perform photoactivation. The yield of the process never reached wild type level, and contrary to the wild type, it was highly dependent on the intensity of the activating light, with a very narrow optimum around 1 µE m2 s1. The different behavior in the mutant can be explained by a requirement for a longer dark period, between the two photoacts, during the photoactivation. This is proposed to reflect the decreased Cl affinity in the mutant. Photoactivation in the mutant was also found to be very sensitive to... (More)
The process of photoactivation has been studied in dark grown cells of Chlamydomonas reinhardtii. A mutant, FUD 39, lacking the Cl-concentrating 23-kDa psbP protein of photosystem II was found to have a decreased capability to perform photoactivation. The yield of the process never reached wild type level, and contrary to the wild type, it was highly dependent on the intensity of the activating light, with a very narrow optimum around 1 µE m2 s1. The different behavior in the mutant can be explained by a requirement for a longer dark period, between the two photoacts, during the photoactivation. This is proposed to reflect the decreased Cl affinity in the mutant. Photoactivation in the mutant was also found to be very sensitive to competing photoinhibitory processes. The inhibition was located to the donor side of photosystem II and affected the photoactivation capability before electron transfer from Tyrz was inhibited. We propose an extended model for photoactivation in which an intermediate that is sensitive to photoinhibition is formed if Cl is not functionally bound to the manganese cluster. (Less)
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organization
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Contribution to journal
publication status
published
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in
Journal of Biological Chemistry
volume
271
issue
46
pages
28918 - 28924
publisher
ASBMB
external identifiers
  • scopus:0029826533
ISSN
1083-351X
language
English
LU publication?
yes
id
bef9c633-79f1-4e0f-93cb-c3a5a0ae3245 (old id 126344)
alternative location
http://www.jbc.org/cgi/reprint/271/46/28918
date added to LUP
2007-07-06 14:37:55
date last changed
2017-02-12 03:25:43
@article{bef9c633-79f1-4e0f-93cb-c3a5a0ae3245,
  abstract     = {The process of photoactivation has been studied in dark grown cells of Chlamydomonas reinhardtii. A mutant, FUD 39, lacking the Cl-concentrating 23-kDa psbP protein of photosystem II was found to have a decreased capability to perform photoactivation. The yield of the process never reached wild type level, and contrary to the wild type, it was highly dependent on the intensity of the activating light, with a very narrow optimum around 1 µE m2 s1. The different behavior in the mutant can be explained by a requirement for a longer dark period, between the two photoacts, during the photoactivation. This is proposed to reflect the decreased Cl affinity in the mutant. Photoactivation in the mutant was also found to be very sensitive to competing photoinhibitory processes. The inhibition was located to the donor side of photosystem II and affected the photoactivation capability before electron transfer from Tyrz was inhibited. We propose an extended model for photoactivation in which an intermediate that is sensitive to photoinhibition is formed if Cl is not functionally bound to the manganese cluster.},
  author       = {Rova, E Maria and Mc Ewen, Birgitta and Fredriksson, Per-Olof and Styring, Stenbjörn},
  issn         = {1083-351X},
  language     = {eng},
  number       = {46},
  pages        = {28918--28924},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {Photoactivation and Photoinhibition Are Competing in a Mutant of Chlamydomonas reinhardtii Lacking the 23-kDa Extrinsic Subunit of Photosystem II},
  volume       = {271},
  year         = {1996},
}