scholarly journals Composition, phosphorylation and dynamic organization of photosynthetic protein complexes in plant thylakoid membrane

2020 ◽  
Vol 19 (5) ◽  
pp. 604-619 ◽  
Author(s):  
Marjaana Rantala ◽  
Sanna Rantala ◽  
Eva-Mari Aro
Keyword(s):  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Protein Network ◽  
Membrane Ultrastructure ◽  
Dynamic Organization ◽  
Photosynthetic Protein Complexes

Here we present an overview of the composition and organization of photosynthetic protein complexes in thylakoid membrane and discuss the consequences of the light-induced protein network re-organization to the thylakoid membrane ultrastructure.

scholarly journals Fast Diffusion of the Unassembled PetC1-GFP Protein in the Cyanobacterial Thylakoid Membrane

Life ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Radek Kaňa ◽  
Gábor Steinbach ◽  
Roman Sobotka ◽  
György Vámosi ◽  
Josef Komenda
Keyword(s):  
Membrane Proteins ◽  
Single Molecule ◽  
Protein Interactions ◽  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Correlation Spectroscopy ◽  
Membrane Microdomains ◽  
Fast Diffusion ◽  
Light Harvesting Complexes ◽  
Term Survival

Biological membranes were originally described as a fluid mosaic with uniform distribution of proteins and lipids. Later, heterogeneous membrane areas were found in many membrane systems including cyanobacterial thylakoids. In fact, cyanobacterial pigment–protein complexes (photosystems, phycobilisomes) form a heterogeneous mosaic of thylakoid membrane microdomains (MDs) restricting protein mobility. The trafficking of membrane proteins is one of the key factors for long-term survival under stress conditions, for instance during exposure to photoinhibitory light conditions. However, the mobility of unbound ‘free’ proteins in thylakoid membrane is poorly characterized. In this work, we assessed the maximal diffusional ability of a small, unbound thylakoid membrane protein by semi-single molecule FCS (fluorescence correlation spectroscopy) method in the cyanobacterium Synechocystis sp. PCC6803. We utilized a GFP-tagged variant of the cytochrome b6f subunit PetC1 (PetC1-GFP), which was not assembled in the b6f complex due to the presence of the tag. Subsequent FCS measurements have identified a very fast diffusion of the PetC1-GFP protein in the thylakoid membrane (D = 0.14 − 2.95 µm2s−1). This means that the mobility of PetC1-GFP was comparable with that of free lipids and was 50–500 times higher in comparison to the mobility of proteins (e.g., IsiA, LHCII—light-harvesting complexes of PSII) naturally associated with larger thylakoid membrane complexes like photosystems. Our results thus demonstrate the ability of free thylakoid-membrane proteins to move very fast, revealing the crucial role of protein–protein interactions in the mobility restrictions for large thylakoid protein complexes.

scholarly journals Optimization of light harvesting and photoprotection: molecular mechanisms and physiological consequences

2012 ◽  
Vol 367 (1608) ◽  
pp. 3455-3465 ◽  
Author(s):  
Peter Horton
Keyword(s):  
Protein Interactions ◽  
Thylakoid Membrane ◽  
Molecular Mechanisms ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Efficient Energy Transfer ◽  
Light Harvesting Complexes ◽  
Functional Flexibility ◽  
Jan Anderson ◽  
Repulsive Forces

The distinctive lateral organization of the protein complexes in the thylakoid membrane investigated by Jan Anderson and co-workers is dependent on the balance of various attractive and repulsive forces. Modulation of these forces allows critical physiological regulation of photosynthesis that provides efficient light-harvesting in limiting light but dissipation of excess potentially damaging radiation in saturating light. The light-harvesting complexes (LHCII) are central to this regulation, which is achieved by phosphorylation of stromal residues, protonation on the lumen surface and de-epoxidation of bound violaxanthin. The functional flexibility of LHCII derives from a remarkable pigment composition and configuration that not only allow efficient absorption of light and efficient energy transfer either to photosystem II or photosystem I core complexes, but through subtle configurational changes can also exhibit highly efficient dissipative reactions involving chlorophyll–xanthophyll and/or chlorophyll–chlorophyll interactions. These changes in function are determined at a macroscopic level by alterations in protein–protein interactions in the thylakoid membrane. The capacity and dynamics of this regulation are tuned to different physiological scenarios by the exact protein and pigment content of the light-harvesting system. Here, the molecular mechanisms involved will be reviewed, and the optimization of the light-harvesting system in different environmental conditions described.

scholarly journals From isolated light-harvesting complexes to the thylakoid membrane: a single-molecule perspective

Nanophotonics ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 81-92 ◽  
Author(s):  
J. Michael Gruber ◽  
Pavel Malý ◽  
Tjaart P.J. Krüger ◽  
Rienk van Grondelle
Keyword(s):  
Single Molecule ◽  
Thylakoid Membrane ◽  
Light Harvesting ◽  
Protein Complexes ◽  
Conformational Dynamics ◽  
Physical Models ◽  
Photochemical Quenching ◽  
Light Harvesting Complexes ◽  
Fluorescence Measurements

AbstractThe conversion of solar radiation to chemical energy in plants and green algae takes place in the thylakoid membrane. This amphiphilic environment hosts a complex arrangement of light-harvesting pigment-protein complexes that absorb light and transfer the excitation energy to photochemically active reaction centers. This efficient light-harvesting capacity is moreover tightly regulated by a photoprotective mechanism called non-photochemical quenching to avoid the stress-induced destruction of the catalytic reaction center. In this review we provide an overview of single-molecule fluorescence measurements on plant light-harvesting complexes (LHCs) of varying sizes with the aim of bridging the gap between the smallest isolated complexes, which have been well-characterized, and the native photosystem. The smallest complexes contain only a small number (10–20) of interacting chlorophylls, while the native photosystem contains dozens of protein subunits and many hundreds of connected pigments. We discuss the functional significance of conformational dynamics, the lipid environment, and the structural arrangement of this fascinating nano-machinery. The described experimental results can be utilized to build mathematical-physical models in a bottom-up approach, which can then be tested on larger in vivo systems. The results also clearly showcase the general property of biological systems to utilize the same system properties for different purposes. In this case it is the regulated conformational flexibility that allows LHCs to switch between efficient light-harvesting and a photoprotective function.

scholarly journals Regulatory factors for the assembly of thylakoid membrane protein complexes

2012 ◽  
Vol 367 (1608) ◽  
pp. 3420-3429 ◽  
Author(s):  
Wei Chi ◽  
Jinfang Ma ◽  
Lixin Zhang
Keyword(s):  
Membrane Protein ◽  
Thylakoid Membrane ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Protein Complexes ◽  
Thylakoid Membranes ◽  
Regulatory Factors ◽  
Photosynthetic Organisms ◽  
Photosynthetic Complexes ◽  
Membrane Protein Complexes

Major multi-protein photosynthetic complexes, located in thylakoid membranes, are responsible for the capture of light and its conversion into chemical energy in oxygenic photosynthetic organisms. Although the structures and functions of these photosynthetic complexes have been explored, the molecular mechanisms underlying their assembly remain elusive. In this review, we summarize current knowledge of the regulatory components involved in the assembly of thylakoid membrane protein complexes in photosynthetic organisms. Many of the known regulatory factors are conserved between prokaryotes and eukaryotes, whereas others appear to be newly evolved or to have expanded predominantly in eukaryotes. Their specific features and fundamental differences in cyanobacteria, green algae and land plants are discussed.

scholarly journals Atomic force microscopy visualizes mobility of photosynthetic proteins in grana thylakoid membranes

2018 ◽  
Author(s):  
Bibiana Onoa ◽  
Shingo Fukuda ◽  
Masakazu Iwai ◽  
Carlos Bustamante ◽  
Krishna K. Niyogi
Keyword(s):  
High Speed ◽  
Spinacia Oleracea ◽  
Protein Complexes ◽  
Rotational Diffusion ◽  
Thylakoid Membranes ◽  
Spatiotemporal Resolution ◽  
Force Microscopy ◽  
Photosynthetic Complexes ◽  
Protein Density ◽  
Photosynthetic Protein Complexes

ABSTRACTThylakoid membranes in chloroplasts contain photosynthetic protein complexes that convert light energy into chemical energy. Photosynthetic protein complexes are considered to undergo structural reorganization to maintain the efficiency of photochemical reactions. A detailed description of the mobility of photosynthetic complexes in real-time is necessary to understand how macromolecular organization of the membrane is altered by environmental fluctuations. Here, we used high-speed atomic force microscopy to visualize and characterize the in situ mobility of individual protein complexes in grana thylakoid membranes isolated from Spinacia oleracea. Our observations reveal that these membranes can harbor complexes with at least two distinctive classes of mobility. A large fraction of grana membranes contained proteins with quasi-static mobility, exhibiting molecular displacements smaller than 10 nm2. In the remaining fraction, the protein mobility is variable with molecular displacements of up to 100 nm2. This visualization at high-spatiotemporal resolution enabled us to estimate an average diffusion coefficient of ∼1 nm2 s-1. Interestingly, both confined and Brownian diffusion models could describe the protein mobility of the second group of membranes. We also provide the first direct evidence of rotational diffusion of photosynthetic complexes. The rotational diffusion of photosynthetic complexes could be an adaptive response to the high protein density in the membrane to guarantee the efficiency of electron transfer reactions. This characterization of the mobility of individual photosynthetic complexes in grana membranes establishes a foundation that could be adapted to study the dynamics of the complexes inside the intact and photosynthetically functional thylakoid membranes to be able to understand its structural responses to diverse environmental fluctuations.STATEMENT OF SIGNIFICANCEWe characterized the dynamics of individual photosynthetic protein complexes in grana thylakoid membranes from Spinacia oleracea by high-speed atomic microscopy (HS-AFM). Direct visualization at high spatiotemporal resolution unveils that the mobility of photosynthetic proteins is heterogeneous but governed by the confinement effect imposed by the high protein density in the thylakoid membrane. The photosynthetic complexes display rotational diffusion, which might be a consequence of the crowded environment in the membrane and a mechanism to sustain an efficient electron transfer chain.

Vipp1 is required for basic thylakoid membrane formation but not for the assembly of thylakoid protein complexes

2007 ◽  
Vol 45 (2) ◽  
pp. 119-128 ◽  
Author(s):  
Elena Aseeva ◽  
Friederich Ossenbühl ◽  
Claudia Sippel ◽  
Won K. Cho ◽  
Bernhard Stein ◽  
...  
Keyword(s):  
Thylakoid Membrane ◽  
Protein Complexes ◽  
Membrane Formation ◽  
Thylakoid Protein
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