Biochemical and molecular properties of LHCX1, the essential regulator of dynamic photoprotection in diatoms

2021 ◽  
Author(s):  
Vasco Giovagnetti ◽  
Marianne Jaubert ◽  
Mahendra K Shukla ◽  
Petra Ungerer ◽  
Jean-Pierre Bouly ◽  
...  
Keyword(s):  
Light Harvesting ◽  
Functional Divergence ◽  
Selective Advantage ◽  
Targeted Mutagenesis ◽  
Intermittent Light ◽  
Light Harvesting Complex ◽  
Dynamic Tracking ◽  
Ecological Success ◽  
Energy Dependent ◽  
Light Harvesting Antenna

Abstract Light harvesting is regulated by a process triggered by the acidification of the thylakoid lumen, known as nonphotochemical “energy-dependent quenching” (qE). In diatoms, qE is controlled by the light-harvesting complex (LHC) protein LHCX1, while the LHC stress-related (LHCSR) and photosystem II subunit S proteins are essential for green algae and plants, respectively. Here, we report a biochemical and molecular characterization of LHCX1 to investigate its role in qE. We found that, when grown under intermittent light, Phaeodactylum tricornutum forms very large qE, due to LHCX1 constitutive upregulation. This “super qE” is abolished in LHCX1 knockout mutants. Biochemical and spectroscopic analyses of LHCX1 reveal that this protein might differ in the character of binding pigments relative to the major pool of light-harvesting antenna proteins. The possibility of transient pigment binding or not binding pigments at all is discussed. Targeted mutagenesis of putative protonatable residues (D95 and E205) in transgenic P. tricornutum lines does not alter qE capacity, showing that they are not involved in sensing lumen pH, differently from residues conserved in LHCSR3. Our results suggest functional divergence between LHCX1 and LHCSR3 in qE modulation. We propose that LHCX1 evolved independently to facilitate dynamic tracking of light fluctuations in turbulent waters. The evolution of LHCX(-like) proteins in organisms with secondary red plastids, such as diatoms, might have conferred a selective advantage in the control of dynamic photoprotection, ultimately resulting in their ecological success.

scholarly journals Excitation energy transfer and equilibration process in LHCII studied by multidimensional electronic spectroscopy

2019 ◽  
Vol 205 ◽  
pp. 09038
Author(s):  
Thanh Nhut Do ◽  
Adriana Huerta-Viga ◽  
Cheng Zhang ◽  
Parveen Akhtar ◽  
Pawei J. Nowakowski ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Light Harvesting ◽  
Electronic Spectroscopy ◽  
Excitation Energy Transfer ◽  
Phenomenological Analysis ◽  
Two Dimensional ◽  
Light Harvesting Complex ◽  
Light Harvesting Complex Ii ◽  
Equilibration Process ◽  
Light Harvesting Antenna

Light-harvesting complex II (LHCII) – the light-harvesting antenna of Photosystem II – is a naturally abundant system that plays an important role in photosynthesis. In this study, we present a phenomenological analysis of the excitonic energy transfer in LHCII using ultrafast two-dimensional electronic spectroscopy, that we find compares well with previous theoretical and experimental results.

scholarly journals Investigations of the role of the main light-harvesting chlorophyll-protein complex in thylakoid membranes. Reconstitution of depleted membranes from intermittent-light-grown plants with the isolated complex.

1984 ◽  
Vol 98 (1) ◽  
pp. 163-172 ◽  
Author(s):  
D A Day ◽  
I J Ryrie ◽  
N Fuad
Keyword(s):  
Photosystem Ii ◽  
Light Harvesting ◽  
Gradient Centrifugation ◽  
Freeze Fracture ◽  
Direct Role ◽  
Lhc Ii ◽  
Intermittent Light ◽  
Light Harvesting Complex ◽  
Thylakoid Stacking

The functions of the light-harvesting complex of photosystem II (LHC-II) have been studied using thylakoids from intermittent-light-grown (IML) plants, which are deficient in this complex. These chloroplasts have no grana stacks and only limited lamellar appression in situ. In vitro the thylakoids showed limited but significant Mg2+-induced membrane appression and a clear segregation of membrane particles into such regions. This observation, together with the immunological detection of small quantities of LHC-II apoproteins, suggests that the molecular mechanism of appression may be similar to the more extensive thylakoid stacking seen in normal chloroplasts and involve LHC-II polypeptides directly. To study LHC-II function directly, a sonication-freeze-thaw procedure was developed for controlled insertion of purified LHC-II into IML membranes. Incorporation was demonstrated by density gradient centrifugation, antibody agglutination tests, and freeze-fracture electron microscopy. The reconstituted membranes, unlike the parent IML membranes, exhibited both extensive membrane appression and increased room temperature fluorescence in the presence of cations, and a decreased photosystem I activity at low light intensity. These membranes thus mimic normal chloroplasts in this regard, suggesting that the incorporated LHC-II interacts with photosystem II centers in IML membranes and exerts a direct role in the regulation of excitation energy distribution between the two photosystems.

scholarly journals UV-B photoreceptor-mediated protection of the photosynthetic machinery inChlamydomonas reinhardtii

2016 ◽  
Vol 113 (51) ◽  
pp. 14864-14869 ◽  
Author(s):  
Guillaume Allorent ◽  
Linnka Lefebvre-Legendre ◽  
Richard Chappuis ◽  
Marcel Kuntz ◽  
Thuy B. Truong ◽  
...  
Keyword(s):  
Photosynthetic Activity ◽  
Light Harvesting ◽  
Nonphotochemical Quenching ◽  
High Light ◽  
Light Energy ◽  
Light Harvesting Complex ◽  
Subsequent Exposure ◽  
Photosynthetic Machinery ◽  
Life On Earth ◽  
Energy Dependent

Life on earth is dependent on the photosynthetic conversion of light energy into chemical energy. However, absorption of excess sunlight can damage the photosynthetic machinery and limit photosynthetic activity, thereby affecting growth and productivity. Photosynthetic light harvesting can be down-regulated by nonphotochemical quenching (NPQ). A major component of NPQ is qE (energy-dependent nonphotochemical quenching), which allows dissipation of light energy as heat. Photodamage peaks in the UV-B part of the spectrum, but whether and how UV-B induces qE are unknown. Plants are responsive to UV-B via the UVR8 photoreceptor. Here, we report in the green algaChlamydomonas reinhardtiithat UVR8 induces accumulation of specific members of the light-harvesting complex (LHC) superfamily that contribute to qE, in particular LHC Stress-Related 1 (LHCSR1) and Photosystem II Subunit S (PSBS). The capacity for qE is strongly induced by UV-B, although the patterns of qE-related proteins accumulating in response to UV-B or to high light are clearly different. The competence for qE induced by acclimation to UV-B markedly contributes to photoprotection upon subsequent exposure to high light. Our study reveals an anterograde link between photoreceptor-mediated signaling in the nucleocytosolic compartment and the photoprotective regulation of photosynthetic activity in the chloroplast.

The Effect of Cd on Chlorophyll and Light-Harvesting Complex II Biosynthesis in Greening Plants

1999 ◽  
Vol 54 (9-10) ◽  
pp. 740-745 ◽  
Author(s):  
Leto Tziveleka ◽  
Athanassios Kaldis ◽  
Attila Hegedüs ◽  
Judit Kissimon ◽  
Anastasia Prombona ◽  
...  
Keyword(s):  
Phaseolus Vulgaris ◽  
Light Harvesting ◽  
Northern Hybridization ◽  
Total Chlorophyll ◽  
Intermittent Light ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

The effect of Cd on chlorophyll (Chl) as well as on light-harvesting complex II (LHCII) accumulation, has been examined during the early stages of development in etiolated Phaseolus vulgaris leaves exposed to intermittent light-dark cycles. We found that at the Cd concentrations studied, both Chl and LHCII accumulation were drastically reduced, although the LDS-solubilized total leaf protein level remained unaffected. However, on the basis of total chlorophyll present, the amount of stabilized LHCII was similar in both Cd-treated and nontreated samples. Additionally, the thylakoid-bound protease known to degrade LHCII, was found to be inhibited by Cd treatment both in vivo and in vitro. Finally, Northern hybridization analysis indicated that Cd affects LHCII accumulation by reducing drastically the steadystate level of Lhcb transcripts

The evolution of the photoprotective antenna proteins in oxygenic photosynthetic eukaryotes

2018 ◽  
Vol 46 (5) ◽  
pp. 1263-1277 ◽  
Author(s):  
Vasco Giovagnetti ◽  
Alexander V. Ruban
Keyword(s):  
Vascular Plants ◽  
Light Harvesting ◽  
Current Knowledge ◽  
Complex Stress ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Photosynthetic Organisms ◽  
Photosynthetic Eukaryotes ◽  
Non Photochemical Quenching ◽  
Energy Dependent

Photosynthetic organisms require rapid and reversible down-regulation of light harvesting to avoid photodamage. Response to unpredictable light fluctuations is achieved by inducing energy-dependent quenching, qE, which is the major component of the process known as non-photochemical quenching (NPQ) of chlorophyll fluorescence. qE is controlled by the operation of the xanthophyll cycle and accumulation of specific types of proteins, upon thylakoid lumen acidification. The protein cofactors so far identified to modulate qE in photosynthetic eukaryotes are the photosystem II subunit S (PsbS) and light-harvesting complex stress-related (LHCSR/LHCX) proteins. A transition from LHCSR- to PsbS-dependent qE took place during the evolution of the Viridiplantae (also known as ‘green lineage’ organisms), such as green algae, mosses and vascular plants. Multiple studies showed that LHCSR and PsbS proteins have distinct functions in the mechanism of qE. LHCX(-like) proteins are closely related to LHCSR proteins and found in ‘red lineage’ organisms that contain secondary red plastids, such as diatoms. Although LHCX proteins appear to control qE in diatoms, their role in the mechanism remains poorly understood. Here, we present the current knowledge on the functions and evolution of these crucial proteins, which evolved in photosynthetic eukaryotes to optimise light harvesting.

scholarly journals Macroscale structural changes of thylakoid architecture during high light acclimation in Chlamydomonas reinhardtii

2021 ◽  
Author(s):  
Mimi Broderson ◽  
Krishna K. Niyogi ◽  
Masakazu Iwai
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Structural Changes ◽  
Light Harvesting ◽  
Structural Response ◽  
Super Resolution ◽  
High Light ◽  
Loss Of Function ◽  
Light Harvesting Complex ◽  
Protein Levels ◽  
Light Harvesting Antenna

Photoprotection mechanisms are ubiquitous among photosynthetic organisms. The photoprotection capacity of the green alga Chlamydomonas reinhardtii is correlated with protein levels of stress-related light-harvesting complex (LHCSR) proteins, which are strongly induced by high light (HL). However, the dynamic response of overall thylakoid structure during acclimation to growth in HL has not been characterized. Here, we combined live-cell super-resolution microscopy and analytical membrane subfractionation to investigate macroscale structural changes of thylakoid membranes during HL acclimation in C. reinhardtii. Subdiffraction-resolution bioimaging revealed that overall thylakoid structures became thinned and shrunken during HL acclimation. The stromal space around the pyrenoid also became enlarged. Analytical density-dependent membrane fractionation indicated that the structural changes were partly a consequence of membrane unstacking. The analysis of both an LHCSR loss-of- function mutant, npq4 lhcsr1, and a regulatory mutant that over-expresses LHCSR, spa1-1, showed that structural changes occurred independently of LHCSR protein levels, demonstrating that LHCSR was neither necessary nor sufficient to induce the thylakoid structural changes associated with HL acclimation. In contrast, stt7-9, a mutant lacking a kinase of major light-harvesting antenna proteins, had a distinct thylakoid structural response during HL acclimation relative to all other lines tested. Thus, while LHCSR and the antenna protein phosphorylation are core features of HL acclimation, it appears that only the latter acts as a determinant for thylakoid structural rearrangements. These results indicate that two independent mechanisms occur simultaneously to cope with HL conditions. Possible scenarios for HL-induced thylakoid structural changes are discussed.

Protein Subunits of Bacteriochlorophylls B 802 and B 855 of the Light-Harvesting Complex II of Rhodopseudomonas capsulata

1979 ◽  
Vol 34 (3-4) ◽  
pp. 196-199 ◽  
Author(s):  
Reiner Feick ◽  
Gerhart Drews
Keyword(s):  
Molecular Weight ◽  
Light Harvesting ◽  
Polyacrylamide Gel Electrophoresis ◽  
Rhodopseudomonas Capsulata ◽  
Ir Absorption ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii ◽  
The One ◽  
Light Harvesting Antenna

Abstract The light-harvesting antenna complex II of Rhodopseudomonas capsulata is characterized by two prominent IR-absorption maxima at 802 and 855 nm and three polypeptides of 14,000, 10,000 and 8,000 molecular weight (SDS-polyacrylamide gel electrophoresis). Bacteriochlorophyll (Bchl) is associated with the two lower molecular weight polypeptides. The membranes of the mutant Y 5, which lades reaction center and light harvesting complex I (B 875), were treated with trypsin. The 14,000 polypeptide was rapidly digested by trypsin, but the absorption spectrum of the membrane and the activity of the cytochrome c oxidase were not altered. Subsequently the 8,000 polypeptide was degraded. The digestion of the 8,000 polypeptide was concomitant with and proportional to the loss of absorbance at 802 nm. The absorption peak at 855 nm and the content of the 10,000 molecular weight polypeptide were, in contrast, stable for a longer time, but were also lost simultaneously.These results, in combination with the recent publications of Sauer and Austin (Biochemistry 17, 2011, 1978), and Cogdell and Crofts (Biochim. Biophys. Acta 502, 409, 1978) support the idea that the two molecules of Bchl associated with the 10,000 polypeptide are responsible for the 855 nm peak while the one or two mol of Bchl associated with 8,000 polypeptide result in the 802 nm absorption maximum.

Macroorganisation and flexibility of thylakoid membranes

2019 ◽  
Vol 476 (20) ◽  
pp. 2981-3018 ◽  
Author(s):  
Petar H. Lambrev ◽  
Parveen Akhtar
Keyword(s):  
Light Harvesting ◽  
Current Knowledge ◽  
Three Dimensional ◽  
Photosynthetic Apparatus ◽  
Dynamic Responses ◽  
State Transitions ◽  
Photochemical Quenching ◽  
Light Harvesting Complex ◽  
Complex Ii ◽  
Light Harvesting Complex Ii

Abstract The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) — the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid–protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Sign in / Sign up

Export Citation Format

Share Document