scholarly journals PHOTOSYSTEM II SUBUNIT R Is Required for Efficient Binding of LIGHT-HARVESTING COMPLEX STRESS-RELATED PROTEIN3 to Photosystem II-Light-Harvesting Supercomplexes in Chlamydomonas reinhardtii

2015 ◽  
Vol 167 (4) ◽  
pp. 1566-1578 ◽  
Author(s):  
Huidan Xue ◽  
Ryutaro Tokutsu ◽  
Sonja Verena Bergner ◽  
Martin Scholz ◽  
Jun Minagawa ◽  
...  
2020 ◽  
Author(s):  
Julianne M. Troiano ◽  
Federico Perozeni ◽  
Raymundo Moya ◽  
Luca Zuliani ◽  
Kwangryul Baek ◽  
...  

AbstractUnder high light conditions, oxygenic photosynthetic organisms avoid photodamage by thermally dissipating excess absorbed energy, which is called non-photochemical quenching (NPQ). In green algae, a chlorophyll and carotenoid-binding protein, light-harvesting complex stress-related (LHCSR3), detects excess energy via pH and serves as a quenching site. However, the mechanisms by which LHCSR3 functions have not been determined. Using a combined in vivo and in vitro approach, we identify two parallel yet distinct quenching processes, individually controlled by pH and carotenoid composition, and their likely molecular origin within LHCSR3 from Chlamydomonas reinhardtii. The pH-controlled quenching is removed within a mutant LHCSR3 that lacks the protonable residues responsible for sensing pH. Constitutive quenching in zeaxanthin-enriched systems demonstrates zeaxanthin-controlled quenching, which may be shared with other light-harvesting complexes. We show that both quenching processes prevent the formation of damaging reactive oxygen species, and thus provide distinct timescales and mechanisms of protection in a changing environment.


1984 ◽  
Vol 98 (1) ◽  
pp. 1-7 ◽  
Author(s):  
F A Wollman ◽  
P Delepelaire

We have used a new method to extensively modify the redox state of the plastoquinone pool in Chlamydomonas reinhardtii intact cells. This was achieved by an anaerobic treatment that inhibits the chlororespiratory pathway recently described by P. Bennoun (Proc. Natl. Acad. Sci. USA, 1982, 79:4352-4356). A state I (plus 3,4-dichlorophenyl-1,1-dimethylurea) leads to anaerobic state transition induced a decrease in the maximal fluorescence yield at room temperature and in the FPSII/FPSI ratio at 77 degrees K, which was three times larger than in a classical state I leads to state II transition. The fluorescence changes observed in vivo were similar in amplitude to those observed in vitro upon transfer to the light of dark-adapted, broken chloroplasts incubated in the presence of ATP. We then compared the phosphorylation pattern of thylakoid polypeptides in C. reinhardtii in vitro and in vivo using gamma-[32P]ATP and [32P]orthophosphate labeling, respectively. The same set of polypeptides, mainly light-harvesting complex polypeptides, was phosphorylated in both cases. We observed that this phosphorylation process is reversible and is mediated by the redox state of the plastoquinone pool in vivo as well as in vitro. Similar changes of even larger amplitude were observed with the F34 mutant intact cells lacking in photosystem II centers. The presence of the photosystem II centers is then not required for the occurrence of the plastoquinone-mediated phosphorylation of light-harvesting complex polypeptides.


2014 ◽  
Vol 26 (4) ◽  
pp. 1598-1611 ◽  
Author(s):  
Sabrina Grewe ◽  
Matteo Ballottari ◽  
Marcelo Alcocer ◽  
Cosimo D’Andrea ◽  
Olga Blifernez-Klassen ◽  
...  

2016 ◽  
Vol 113 (27) ◽  
pp. 7673-7678 ◽  
Author(s):  
Emine Dinc ◽  
Lijin Tian ◽  
Laura M. Roy ◽  
Robyn Roth ◽  
Ursula Goodenough ◽  
...  

To avoid photodamage, photosynthetic organisms are able to thermally dissipate the energy absorbed in excess in a process known as nonphotochemical quenching (NPQ). Although NPQ has been studied extensively, the major players and the mechanism of quenching remain debated. This is a result of the difficulty in extracting molecular information from in vivo experiments and the absence of a validation system for in vitro experiments. Here, we have created a minimal cell of the green alga Chlamydomonas reinhardtii that is able to undergo NPQ. We show that LHCII, the main light harvesting complex of algae, cannot switch to a quenched conformation in response to pH changes by itself. Instead, a small amount of the protein LHCSR1 (light-harvesting complex stress related 1) is able to induce a large, fast, and reversible pH-dependent quenching in an LHCII-containing membrane. These results strongly suggest that LHCSR1 acts as pH sensor and that it modulates the excited state lifetimes of a large array of LHCII, also explaining the NPQ observed in the LHCSR3-less mutant. The possible quenching mechanisms are discussed.


eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Julianne M Troiano ◽  
Federico Perozeni ◽  
Raymundo Moya ◽  
Luca Zuliani ◽  
Kwangyrul Baek ◽  
...  

Under high light, oxygenic photosynthetic organisms avoid photodamage by thermally dissipating absorbed energy, which is called nonphotochemical quenching. In green algae, a chlorophyll and carotenoid-binding protein, light-harvesting complex stress-related (LHCSR3), detects excess energy via a pH drop and serves as a quenching site. Using a combined in vivo and in vitro approach, we investigated quenching within LHCSR3 from Chlamydomonas reinhardtii. In vitro two distinct quenching processes, individually controlled by pH and zeaxanthin, were identified within LHCSR3. The pH-dependent quenching was removed within a mutant LHCSR3 that lacks the residues that are protonated to sense the pH drop. Observation of quenching in zeaxanthin-enriched LHCSR3 even at neutral pH demonstrated zeaxanthin-dependent quenching, which also occurs in other light-harvesting complexes. Either pH- or zeaxanthin-dependent quenching prevented the formation of damaging reactive oxygen species, and thus the two quenching processes may together provide different induction and recovery kinetics for photoprotection in a changing environment.


2021 ◽  
Author(s):  
Ingrid Guarnetti Prandi ◽  
Vladislav Sláma ◽  
Cristina Pecorilla ◽  
Lorenzo Cupellini ◽  
Benedetta Mennucci

Light-harvesting complexes (LHCs) are pigment-protein complexes whose main function is to capture sunlight and transfer the energy to reaction centers of photosystems. In response to varying light conditions, LH complexes also play photoregulation and photoprotection roles. In algae and mosses, a sub-family of LHCs, Light-Harvesting complex stress related (LHCSR), is responsible for photoprotective quenching. Despite their functional and evolutionary importance, no direct structural information on LHCSRs is available that can explain their unique properties. In this work we propose a structural model of LHCSR1 from the moss P. Patens, obtained through an integrated computational strategy that combines homology modeling, molecular dynamics, and multiscale quantum chemical calculations. The model is validated by reproducing the spectral properties of LHCSR1. Our model reveals the structural specificity of LHCSR1, as compared with the CP29 LH complex, and poses the basis for understanding photoprotective quenching in mosses.


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