The low molecular weight protein PsaI stabilizes the light-harvesting complex II docking site of photosystem I
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The low molecular weight protein PsaI stabilizes the light-harvesting complex II docking site of photosystem I. / Plöchinger, Magdalena; Torabi, Salar; Rantala, Marjaana; Tikkanen, Mikko; Suorsa, Marjaana; Jensen, Poul Erik; Aro, Eva Mari; Meurer, Jörg.
I: Plant Physiology, Bind 172, Nr. 1, 2016, s. 450-463.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - The low molecular weight protein PsaI stabilizes the light-harvesting complex II docking site of photosystem I
AU - Plöchinger, Magdalena
AU - Torabi, Salar
AU - Rantala, Marjaana
AU - Tikkanen, Mikko
AU - Suorsa, Marjaana
AU - Jensen, Poul Erik
AU - Aro, Eva Mari
AU - Meurer, Jörg
N1 - © 2016 American Society of Plant Biologists. All rights reserved.
PY - 2016
Y1 - 2016
N2 - PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of PsaI destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated phosphorylation level of the LHCII under normal growth light conditions. Remarkably, LHCII was rapidly phosphorylated in ΔpsaI in darkness even after illumination with far-red light. We found that this dark phosphorylation also occurs in previously described mutants impaired in PSI function or state transition. A prompt shift of the plastoquinone (PQ) pool into a more reduced redox state in the dark caused an enhanced LHCII phosphorylation in ΔpsaI Since the redox status of the PQ pool is functionally connected to a series of physiological, biochemical, and gene expression reactions, we propose that the shift of mutant plants into state 2 in darkness represents a compensatory and/or protective metabolic mechanism. This involves an increased reduction and/or reduced oxidation of the PQ pool, presumably to sustain a balanced excitation of both photosystems upon the onset of light.
AB - PsaI represents one of three low molecular weight peptides of PSI. Targeted inactivation of the plastid PsaI gene in Nicotiana tabacum has no measurable effect on photosynthetic electron transport around PSI or on accumulation of proteins involved in photosynthesis. Instead, the lack of PsaI destabilizes the association of PsaL and PsaH to PSI, both forming the light-harvesting complex (LHC)II docking site of PSI. These alterations at the LHCII binding site surprisingly did not prevent state transition but led to an increased incidence of PSI-LHCII complexes, coinciding with an elevated phosphorylation level of the LHCII under normal growth light conditions. Remarkably, LHCII was rapidly phosphorylated in ΔpsaI in darkness even after illumination with far-red light. We found that this dark phosphorylation also occurs in previously described mutants impaired in PSI function or state transition. A prompt shift of the plastoquinone (PQ) pool into a more reduced redox state in the dark caused an enhanced LHCII phosphorylation in ΔpsaI Since the redox status of the PQ pool is functionally connected to a series of physiological, biochemical, and gene expression reactions, we propose that the shift of mutant plants into state 2 in darkness represents a compensatory and/or protective metabolic mechanism. This involves an increased reduction and/or reduced oxidation of the PQ pool, presumably to sustain a balanced excitation of both photosystems upon the onset of light.
KW - Journal Article
U2 - 10.1104/pp.16.00647
DO - 10.1104/pp.16.00647
M3 - Journal article
C2 - 27406169
VL - 172
SP - 450
EP - 463
JO - Plant Physiology
JF - Plant Physiology
SN - 0032-0889
IS - 1
ER -
ID: 169103118