The Relationship between the Binding of Dicyclohexylcarbodiimide and Quenching of Chlorophyll Fluorescence in the Light-Harvesting Proteins of Photosystem II†

Biochemistry ◽  
1998 ◽  
Vol 37 (33) ◽  
pp. 11586-11591 ◽  
Author(s):  
Alexander V. Ruban ◽  
Paolo Pesaresi ◽  
Ulrich Wacker ◽  
Klaus-Dieter J. Irrgang ◽  
Roberto Bassi ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Light Harvesting ◽  
The Relationship

scholarly journals Live-cell imaging of photosystem II antenna dissociation during state transitions

2009 ◽  
Vol 107 (5) ◽  
pp. 2337-2342 ◽  
Author(s):  
Masakazu Iwai ◽  
Makio Yokono ◽  
Noriko Inada ◽  
Jun Minagawa
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Light Harvesting ◽  
Live Cells ◽  
State Transitions ◽  
Fluorescence Lifetime Imaging ◽  
Energy Redistribution ◽  
Dominant Component ◽  
Light Harvesting Antenna

Plants and green algae maintain efficient photosynthesis under changing light environments by adjusting their light-harvesting capacity. It has been suggested that energy redistribution is brought about by shuttling the light-harvesting antenna complex II (LHCII) between photosystem II (PSII) and photosystem I (PSI) (state transitions), but such molecular remodeling has never been demonstrated in vivo. Here, using chlorophyll fluorescence lifetime imaging microscopy, we visualized phospho-LHCII dissociation from PSII in live cells of the green alga Chlamydomonas reinhardtii. Induction of energy redistribution in wild-type cells led to an increase in, and spreading of, a 250-ps lifetime chlorophyll fluorescence component, which was not observed in the stt7 mutant incapable of state transitions. The 250-ps component was also the dominant component in a mutant containing the light-harvesting antenna complexes but no photosystems. The appearance of the 250-ps component was accompanied by activation of LHCII phosphorylation, supporting the visualization of phospho-LHCII dissociation. Possible implications of the unbound phospho-LHCII on energy dissipation are discussed.

Regulation of Non-Photochemical Quenching of Chlorophyll Fluorescence in Plants

1995 ◽  
Vol 22 (2) ◽  
pp. 221 ◽  
Author(s):  
AV Ruban ◽  
P Horton
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Excited States ◽  
Light Harvesting ◽  
Structure And Function ◽  
Photochemical Quenching ◽  
Dynamic Nature ◽  
Dissipation Of Energy ◽  
And Function ◽  
Non Photochemical Quenching

Non-photochemical quenching of chlorophyll fluorescence indicates the de-excitation of light-generated excited states in the chlorophyll associated with photosystem II (PSII). The principle process contributing to this quenching is dependent on the formation of the thylakoid proton gradient and is an important mechanism for protecting PSII from photodamage. Evidence points to the importance of the light-harvesting chlorophyll proteins as the site of dissipation of energy, and suggests that the structure and function of these proteins are regulated by protonation and the ratio of zeaxanthin to violaxanthin. The minor light-harvesting proteins may have a particularly important role as the primary sites of proton binding and because of their enrichment in xanthophyll cycle carotenoids. The dynamic nature of the light-harvesting system is an important part of the process by which plants are able to adapt to different light environments.

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