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A structure of the relict phycobilisome from a thylakoid-free cyanobacterium
Phycobilisomes are megacomplexes in cyanobacteria that capture light. Here, authors characterize a relict paddle-shaped phycobilisome structure, revealing phycobilisome diversity prior to the development of thylakoids.
- Han-Wei Jiang
- , Hsiang-Yi Wu
- & Ming-Yang Ho
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Article
| Open Access
Structure of a monomeric photosystem I core associated with iron-stress-induced-A proteins from Anabaena sp. PCC 7120
IsiAs are unique light-harvesting complexes in cyanobacteria. Here, authors solved the structure of a PSI monomer associated with six IsiAs from Anabaena by cryo-EM, which provide insights into molecular diversity and functions of different IsiAs.
- Ryo Nagao
- , Koji Kato
- & Jian-Ren Shen
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Article
| Open Access
Uphill energy transfer mechanism for photosynthesis in an Antarctic alga
A light-harvesting chlorophyll-binding protein complex from an Antarctic green alga called Prasiola crispa can excite photosystem II with low energy far-red light. Here, through Cryo-EM analysis, the authors reveal its ring-shaped structure with 11-fold symmetry at 3.13 Å resolution.
- Makiko Kosugi
- , Masato Kawasaki
- & Toshiya Senda
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Article
| Open Access
Molecular asymmetry of a photosynthetic supercomplex from green sulfur bacteria
Cryo-EM reveals an asymmetric bacterial photosynthetic supercomplex built upon a homodimeric reaction center core. The structure provides mechanistic insights into light excitation transfer and a possible evolutionary transition intermediate of photosynthetic machinery.
- Ryan Puskar
- , Chloe Du Truong
- & Po-Lin Chiu
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Article
| Open Access
The antenna of far-red absorbing cyanobacteria increases both absorption and quantum efficiency of Photosystem II
Some cyanobacteria acclimate to far-red light by integrating chlorophyll f into their photosystems. Additional chlorophylls typically slow down charge separation but here the authors show that charge separation in chlorophyll-f-containing Photosystem II is faster in the presence of red-shifted allophycocyanin antennas.
- Vincenzo Mascoli
- , Ahmad Farhan Bhatti
- & Roberta Croce
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Article
| Open Access
Exact simulation of pigment-protein complexes unveils vibronic renormalization of electronic parameters in ultrafast spectroscopy
Multimode vibronic mixing in model photosynthetic systems revealed by numerically exact simulations is shown to strongly modify linear and non-linear optical responses and facilitate the persistence of coherent dynamics.
- F. Caycedo-Soler
- , A. Mattioni
- & M. B. Plenio
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Article
| Open Access
Structural basis for different types of hetero-tetrameric light-harvesting complexes in a diatom PSII-FCPII supercomplex
Fucoxanthin chlorophyll a/c-binding proteins (FCPs) harvest light energy in diatoms. The authors analyzed a structure of PSII-FCPII supercomplex at high resolution by cryo-EM, which identified each FCP subunit and pigment network in the supercomplex.
- Ryo Nagao
- , Koji Kato
- & Jian-Ren Shen
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Article
| Open Access
Plant LHC-like proteins show robust folding and static non-photochemical quenching
Plant light harvesting complex (LHC)‐like proteins protect the photosynthetic machinery from excess light. Here the authors show that plant LHC‐like dimers are stabilized by associated pigments and can quench chlorophyll fluorescence via direct energy transfer from chlorophyll to zeaxanthin.
- Petra Skotnicová
- , Hristina Staleva-Musto
- & Roman Sobotka
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Article
| Open Access
Scaffolding proteins guide the evolution of algal light harvesting antennas
Cryptophytes acquired plastids from red algae but replaced the light-harvesting phycobilisome with a unique cryptophyte antenna. Here via analysis of phycobilisome cryo-EM structures, Rathbone et al. propose that the α subunit of the cryptophyte antenna originated from phycobilisome linker proteins
- Harry W. Rathbone
- , Katharine A. Michie
- & Paul M. G. Curmi
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Article
| Open Access
Role of an ancient light-harvesting protein of PSI in light absorption and photoprotection
LHCR proteins are ancient chlorophyll a-binding antennas that evolved in diverse algae of the red lineage. Here Lu et al. characterize a red lineage LHCR mutant and show reduced oxidative damage in high light but attenuated growth under low light, thus demonstrating how LHCR proteins impact the balance between photoprotection and light harvesting.
- Yandu Lu
- , Qinhua Gan
- & Krishna K. Niyogi
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Article
| Open Access
The role of mixed vibronic Qy-Qx states in green light absorption of light-harvesting complex II
The green component of the solar spectrum can efficiently drive natural photosynthesis, but the process has been little investigated due to the complexity of the excited states involved. Here the authors utilize polarization-dependent two-dimensional electronic-vibrational spectroscopy to define the origin and dynamics of these states in light-harvesting complex II.
- Eric A. Arsenault
- , Yusuke Yoneda
- & Graham R. Fleming
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Article
| Open Access
Structural basis for assembly and function of a diatom photosystem I-light-harvesting supercomplex
One of the major photosynthetic light-harvesting complexes (LHCs) are fucoxanthin chlorophyll a/c-binding proteins (FCPs), which are present in diatoms, a major group of algae. Here, the authors present the cryo-EM structure of the photosystem I-FCP (PSI-FCPI) supercomplex isolated from the marine centric diatom Chaetoceros gracilis that contains 16 FCPI subunits surrounding the PSI core and discuss possible excitation energy transfer pathways.
- Ryo Nagao
- , Koji Kato
- & Fusamichi Akita
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Article
| Open Access
Polychromatic solar energy conversion in pigment-protein chimeras that unite the two kingdoms of (bacterio)chlorophyll-based photosynthesis
The spectra of light used by photosynthetic organisms are determined by their pigmentation colour palettes. Here Liu et al. show that a genetically-encoded chimera of light-harvesting proteins from plants and reaction centres from purple bacteria allows for polychromatic solar energy harvesting.
- Juntai Liu
- , Vincent M. Friebe
- & Michael R. Jones
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| Open Access
Observation of dissipative chlorophyll-to-carotenoid energy transfer in light-harvesting complex II in membrane nanodiscs
Resolving the kinetics of energy dissipation during photosynthesis is challenging due to complex photophysics and the coexistence of multiple antenna proteins. Here Son et al. overcome this by applying ultrabroadband 2D spectroscopy to LHCII reconstituted in lipid nanodiscs, revealing mechanisms of dissipation enhanced by the membrane.
- Minjung Son
- , Alberta Pinnola
- & Gabriela S. Schlau-Cohen
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Article
| Open Access
Biomimetic light-harvesting funnels for re-directioning of diffuse light
Sunlight harvesting and redirection is a promising concept for sustainable energy conversion, however losses have hindered progress. Here the authors construct a simple biomimetic device which minimises losses by using reservoirs of randomly-oriented dyes to funnel energy onto individual emitting parallel acceptors.
- Alexander Pieper
- , Manuel Hohgardt
- & Peter Jomo Walla
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Article
| Open Access
Different carotenoid conformations have distinct functions in light-harvesting regulation in plants
Carotenoids can dissipate excess energy captured by photosynthetic light-harvesting complexes to prevent photodamage. Here, via spectroscopic and in silico approaches, Liguori et al. resolve different carotenoid dark states and propose conformational changes that permit them to act as either energy donors or quenchers.
- Nicoletta Liguori
- , Pengqi Xu
- & Roberta Croce
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| Open Access
Mapping the ultrafast flow of harvested solar energy in living photosynthetic cells
During photosynthesis, energy is transferred from photosynthetic antenna to reaction centers via ultrafast energy transfer. Here the authors track energy transfer in photosynthetic bacteria using two-dimensional electronic spectroscopy and show that these transfer dynamics constrain antenna complex organization.
- Peter D. Dahlberg
- , Po-Chieh Ting
- & Gregory S. Engel
Structural insights into photosystem II supercomplex and trimeric FCP antennae of a centric diatom Cyclotella meneghiniana