scholarly journals Diversification of light capture ability was accompanied by the evolution of phycobiliproteins in cryptophyte algae

2019 ◽  
Vol 286 (1902) ◽  
pp. 20190655 ◽  
Author(s):  
Matthew J. Greenwold ◽  
Brady R. Cunningham ◽  
Eric M. Lachenmyer ◽  
John Michael Pullman ◽  
Tammi L. Richardson ◽  
...  

Evolutionary biologists have long sought to identify phenotypic traits whose evolution enhances an organism's performance in its environment. Diversification of traits related to resource acquisition can occur owing to spatial or temporal resource heterogeneity. We examined the ability to capture light in the Cryptophyta, a phylum of single-celled eukaryotic algae with diverse photosynthetic pigments, to better understand how acquisition of an abiotic resource may be associated with diversification. Cryptophytes originated through secondary endosymbiosis between an unknown eukaryotic host and a red algal symbiont. This merger resulted in distinctive pigment–protein complexes, the cryptophyte phycobiliproteins, which are the products of genes from both ancestors. These novel complexes may have facilitated diversification across environments where the spectrum of light available for photosynthesis varies widely. We measured light capture and pigments under controlled conditions in a phenotypically and phylogenetically diverse collection of cryptophytes. Using phylogenetic comparative methods, we found that phycobiliprotein characteristics were evolutionarily associated with diversification of light capture in cryptophytes, while non-phycobiliprotein pigments were not. Furthermore, phycobiliproteins were evolutionarily labile with repeated transitions and reversals. Thus, the endosymbiotic origin of cryptophyte phycobiliproteins provided an evolutionary spark that drove diversification of light capture, the resource that is the foundation of photosynthesis.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Harry W. Rathbone ◽  
Katharine A. Michie ◽  
Michael J. Landsberg ◽  
Beverley R. Green ◽  
Paul M. G. Curmi

AbstractPhotosynthetic organisms have developed diverse antennas composed of chromophorylated proteins to increase photon capture. Cryptophyte algae acquired their photosynthetic organelles (plastids) from a red alga by secondary endosymbiosis. Cryptophytes lost the primary red algal antenna, the red algal phycobilisome, replacing it with a unique antenna composed of αβ protomers, where the β subunit originates from the red algal phycobilisome. The origin of the cryptophyte antenna, particularly the unique α subunit, is unknown. Here we show that the cryptophyte antenna evolved from a complex between a red algal scaffolding protein and phycoerythrin β. Published cryo-EM maps for two red algal phycobilisomes contain clusters of unmodelled density homologous to the cryptophyte-αβ protomer. We modelled these densities, identifying a new family of scaffolding proteins related to red algal phycobilisome linker proteins that possess multiple copies of a cryptophyte-α-like domain. These domains bind to, and stabilise, a conserved hydrophobic surface on phycoerythrin β, which is the same binding site for its primary partner in the red algal phycobilisome, phycoerythrin α. We propose that after endosymbiosis these scaffolding proteins outcompeted the primary binding partner of phycoerythrin β, resulting in the demise of the red algal phycobilisome and emergence of the cryptophyte antenna.


2013 ◽  
Vol 453 (1) ◽  
pp. 304-307 ◽  
Author(s):  
A. A. Ashikhmin ◽  
Yu. E. Erokhin ◽  
Z. K. Makhneva ◽  
A. A. Moskalenko

Author(s):  
Navassard V. Karapetyan ◽  
Marina G. Rakhimberdieva ◽  
Yulia V. Bolychevtseva ◽  
Andrei A. Moskalenko ◽  
Nina Yu. Kuznetsova ◽  
...  

2022 ◽  
Author(s):  
Xin Liu ◽  
Wojciech J Nawrocki ◽  
Roberta Croce

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.


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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