scholarly journals Degradation of the D1 Protein of Photosystem-II Reaction Centre by Ultraviolet-B Radiation Requires the Presence of Functional Manganese on the Donor Side

2008 ◽  
Vol 227 (3) ◽  
pp. 723-729
Author(s):  
Roberto Barbato ◽  
Annalisa Frizzo ◽  
Giulia Friso ◽  
Fernanda Rigoni ◽  
Giorgio M. Giacometti
Keyword(s):  
Photosystem Ii ◽  
D1 Protein ◽  
Ultraviolet B ◽  
Reaction Centre ◽  
Donor Side ◽  
Ultraviolet B Radiation

Degradation of the D1 Protein of Photosystem-II Reaction Centre by Ultraviolet-B Radiation Requires the Presence of Functional Manganese on the Donor Side

1995 ◽  
Vol 227 (3) ◽  
pp. 723-729 ◽  
Author(s):  
Roberto Barbato ◽  
Annalisa Frizzo ◽  
Giulia Friso ◽  
Fernanda Rigoni ◽  
Giorgio M. Giacometti
Keyword(s):  
Photosystem Ii ◽  
D1 Protein ◽  
Ultraviolet B ◽  
Reaction Centre ◽  
Donor Side ◽  
Ultraviolet B Radiation

Ultraviolet-B Induced Damage to Photosystem II in Intact Filaments of Spirulina platensis

1998 ◽  
Vol 53 (5-6) ◽  
pp. 369-377 ◽  
Author(s):  
Bala Krishna Kolli ◽  
Swati Tiwari ◽  
Prasanna Mohanty
Keyword(s):  
Energy Transfer ◽  
Photosystem Ii ◽  
Chlorophyll A ◽  
Spirulina Platensis ◽  
Pool Size ◽  
Ultraviolet B ◽  
Emission Characteristics ◽  
Reaction Centre ◽  
Small Shift ◽  
Ultraviolet B Radiation

Abstract When Spirulina platensis filaments were exposed to 0.75 mW.m-2.s-1 of ultraviolet-B radiation (the ultraviolet-B radiation under clear sky condition is ~1.0 mW.m-2.s-1), an inhibition in photosystem II activity was observed, the inhibition being 90% after 90 min exposure. Upon exposure to ultraviolet-B, the room temperature emission characteristics of Spirulina cells were altered when excited with light primarily absorbed by chlorophyll a or phycobilisomes. When the cells were exposed for 3 h the emission at 685 nm (F685), when excited at 440 nm (primarily chlorophyll a absorption), was enhanced compared to 715 nm (F 715) band of photosystem I suggesting a decrease in energy transfer from photosystem II to photosys­ tem I. Similarly, when the cells were excited at 580 nm (primarily the phycobilisomes), the ratio of emission intensity at 685 nm (F685) to that of 655 nm (F655) was decreased in the exposed cells. This change in emission characteristics seems to be linked with the uncoupling of the energy transfer from allophycocyanin to chlorophyll a of photosystem II. A small shift in emission peak positions was also indicated when excited either at 440 nm or 580 nm. Analysis of the fast induction of chlorophyll a transients in the presence and absence of 10 μm 3-(3,4-dichlorophenyl)-l,l-dimethylurea (DCMU) indicated that ultraviolet-B expo­ sure initially affects Qᴀ, the primary stable acceptor of photosystem II, and then the plastoquinone (PQ) pool. Our results on the loss in photosystem Il-catalyzed Hill activity with p-benzoquinone or dichlorobenzoquinone as electron acceptors also supports the contention that ultraviolet-B, even at low dose, initially alters the Qᴀ of photosystem II and subsequently PQ pool. The analysis of functional pool size of Spirulina suggests a substantial decrease in the functional pool size after 2 h UV-B exposure. These results indicate that in Spirulina low intensity of ultraviolet-B initially damages the reaction centre of photosystem II.

Effects of Ultraviolet-B Radiation on Photosystem II of the Cyanobacterium Synechocystis sp. PCC 6083

1996 ◽  
Vol 242 (3) ◽  
pp. 799-806 ◽  
Author(s):  
Giorgio Mario Giacometti ◽  
Roberto Barbato ◽  
Simona Chiaramonte ◽  
Giulia Friso ◽  
Fernanda Rigoni
Keyword(s):  
Photosystem Ii ◽  
Ultraviolet B ◽  
Ultraviolet B Radiation ◽  
Synechocystis Sp

A possible relation between the function of photosystem II in oxygen evolution and the variable chlorophyll fluorescence

1989 ◽  
Vol 238 (1291) ◽  
pp. 127-136
Keyword(s):  
Chlorophyll Fluorescence ◽  
Photosystem Ii ◽  
Reaction Centre ◽  
Redox Potentials ◽  
Donor Side ◽  
Hypothetical Model ◽  
Surplus Energy ◽  
Variable Chlorophyll Fluorescence ◽  
And Function ◽  
Energy Dependent

A hypothetical model for the structure and function of photosystem II is proposed that attempts to incorporate different phenomena related to the variable chlorophyll fluorescence inherent in this photosystem. The involvement of pheophytin redox chemistry on both the acceptor and donor side of photosystem II is postulated to achieve redox potentials high enough to oxidize water. The presence of this symmetry would be the cause of inefficient photochemistry in photosystem II when, under unbalanced carbon metabolism, a surplus charge remains on the reaction centre. In addition, such a scheme would enable an efficient dissipation of surplus energy in the reaction centre itself, and would be the origin ofthe ‘energy-dependent’ quenching of chlorophyll fluorescence, q ( E ).

scholarly journals The Arabidopsis PsbO2 protein regulates dephosphorylation and turnover of the photosystem II reaction centre D1 protein

2007 ◽  
Vol 49 (3) ◽  
pp. 528-539 ◽  
Author(s):  
Björn Lundin ◽  
Maria Hansson ◽  
Benoît Schoefs ◽  
Alexander V. Vener ◽  
Cornelia Spetea
Keyword(s):  
Photosystem Ii ◽  
D1 Protein ◽  
Reaction Centre

scholarly journals Ultraviolet-B Radiation Impacts Light-Mediated Turnover of the Photosystem II Reaction Center Heterodimer in Arabidopsis Mutants Altered in Phenolic Metabolism

2000 ◽  
Vol 124 (3) ◽  
pp. 1275-1284 ◽  
Author(s):  
Isabelle S. Booij-James ◽  
Shyam K. Dube ◽  
Marcel A.K. Jansen ◽  
Marvin Edelman ◽  
Autar K. Mattoo
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Ultraviolet B ◽  
Phenolic Metabolism ◽  
Arabidopsis Mutants ◽  
Ultraviolet B Radiation
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