Chlorophyll Photobleaching in Pigment-Protein Complexes

1986 ◽  
Vol 41 (3) ◽  
pp. 284-290 ◽  
Author(s):  
Robert Carpentier ◽  
Roger M. Leblanc ◽  
Guy Bellemare
Keyword(s):  
Energy Transfer ◽  
Hordeum Vulgare ◽  
Chlamydomonas Reinhardtii ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Wild Type ◽  
Protection Mechanism ◽  
Long Wavelength ◽  
Pigment Protein Complexes ◽  
Type Mutant

Pigment photobleaching was performed in thylakoid membranes of Hordeum vulgare (wild type, mutant Chlorina f2, Norfluranzon treated seedlings) and in pigment-protein complexes (CP-I and LHCP) isolated from H. vulgare and Chlamydomonas reinhardtii. Multiphasic kinetics were obtained in all of the above cases. Energy transfer towards pigments absorbing at longer wavelength is postulated as a general protection mechanism against photobleaching. This mechanism explains a substantial bleaching of carotenoids and a faster bleaching of chlorophyll aggregates, absorbing at long wavelength. These conclusions were valid for isolated complexes as well as for thylakoid membranes, although membranes were less sensitive to light.

scholarly journals The role of LHCBM1 in non-photochemical quenching in Chlamydomonas reinhardtii

2022 ◽  
Author(s):  
Xin Liu ◽  
Wojciech J Nawrocki ◽  
Roberta Croce
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Protein Complexes ◽  
Ph Sensor ◽  
High Light ◽  
Photochemical Quenching ◽  
Knock Out ◽  
Photosynthetic Organisms ◽  
Pigment Protein Complexes ◽  
Non Photochemical Quenching

Non-photochemical quenching (NPQ) is the process that protects photosynthetic organisms from photodamage by dissipating the energy absorbed in excess as heat. In the model green alga Chlamydomonas reinhardtii, NPQ was abolished in the knock-out mutants of the pigment-protein complexes LHCSR3 and LHCBM1. However, while LHCSR3 was shown to be a pH sensor and switching to a quenched conformation at low pH, the role of LHCBM1 in NPQ has not been elucidated yet. In this work, we combine biochemical and physiological measurements to study short-term high light acclimation of npq5, the mutant lacking LHCBM1. We show that while in low light in the absence of this complex, the antenna size of PSII is smaller than in its presence, this effect is marginal in high light, implying that a reduction of the antenna is not responsible for the low NPQ. We also show that the mutant expresses LHCSR3 at the WT level in high light, indicating that the absence of this complex is also not the reason. Finally, NPQ remains low in the mutant even when the pH is artificially lowered to values that can switch LHCSR3 to the quenched conformation. It is concluded that both LHCSR3 and LHCBM1 need to be present for the induction of NPQ and that LHCBM1 is the interacting partner of LHCSR3. This interaction can either enhance the quenching capacity of LHCSR3 or connect this complex with the PSII supercomplex.

scholarly journals A photosynthetic antenna complex foregoes unity carotenoid-to-bacteriochlorophyll energy transfer efficiency to ensure photoprotection

2020 ◽  
Vol 117 (12) ◽  
pp. 6502-6508 ◽  
Author(s):  
Dariusz M. Niedzwiedzki ◽  
David J. K. Swainsbury ◽  
Daniel P. Canniffe ◽  
C. Neil Hunter ◽  
Andrew Hitchcock
Keyword(s):  
Energy Transfer ◽  
Transient Absorption ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Fluorescence Emission ◽  
Energy Transfer Efficiency ◽  
Transfer Efficiency ◽  
Light Harvesting Complexes ◽  
Antenna Complex ◽  
Pigment Protein Complexes

Carotenoids play a number of important roles in photosynthesis, primarily providing light-harvesting and photoprotective energy dissipation functions within pigment–protein complexes. The carbon–carbon double bond (C=C) conjugation length of carotenoids (N), generally between 9 and 15, determines the carotenoid-to-(bacterio)chlorophyll [(B)Chl] energy transfer efficiency. Here we purified and spectroscopically characterized light-harvesting complex 2 (LH2) fromRhodobacter sphaeroidescontaining theN= 7 carotenoid zeta (ζ)-carotene, not previously incorporated within a natural antenna complex. Transient absorption and time-resolved fluorescence show that, relative to the lifetime of the S1state of ζ-carotene in solvent, the lifetime decreases ∼250-fold when ζ-carotene is incorporated within LH2, due to transfer of excitation energy to the B800 and B850 BChlsa. These measurements show that energy transfer proceeds with an efficiency of ∼100%, primarily via the S1→ Qxroute because the S1→ S0fluorescence emission of ζ-carotene overlaps almost perfectly with the Qxabsorption band of the BChls. However, transient absorption measurements performed on microsecond timescales reveal that, unlike the nativeN≥ 9 carotenoids normally utilized in light-harvesting complexes, ζ-carotene does not quench excited triplet states of BChla, likely due to elevation of the ζ-carotene triplet energy state above that of BChla. These findings provide insights into the coevolution of photosynthetic pigments and pigment–protein complexes. We propose that theN≥ 9 carotenoids found in light-harvesting antenna complexes represent a vital compromise that retains an acceptable level of energy transfer from carotenoids to (B)Chls while allowing acquisition of a new, essential function, namely, photoprotective quenching of harmful (B)Chl triplets.

Strong light-induced reorganization of pigment–protein complexes of thylakoid membranes in rye (spectroscopic study)

2012 ◽  
Vol 169 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Ewa Janik ◽  
Waldemar Maksymiec ◽  
Wojciech Grudziński ◽  
Wiesław I. Gruszecki
Keyword(s):  
Spectroscopic Study ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Strong Light ◽  
Pigment Protein Complexes

scholarly journals Differential Mobility of Pigment-Protein Complexes in Granal and Agranal Thylakoid Membranes of C3 and C4 Plants

2012 ◽  
Vol 161 (1) ◽  
pp. 497-507 ◽  
Author(s):  
Helmut Kirchhoff ◽  
Richard M. Sharpe ◽  
Miroslava Herbstova ◽  
Robert Yarbrough ◽  
Gerald E. Edwards
Keyword(s):  
Protein Complexes ◽  
Thylakoid Membranes ◽  
C4 Plants ◽  
C3 And C4 Plants ◽  
Differential Mobility ◽  
Pigment Protein Complexes
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