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Jiang HW, Wu HY, Wang CH, Yang CH, Ko JT, Ho HC, Tsai MD, Bryant DA, Li FW, Ho MC, Ho MY. A structure of the relict phycobilisome from a thylakoid-free cyanobacterium. Nat Commun 2023; 14:8009. [PMID: 38049400 PMCID: PMC10696076 DOI: 10.1038/s41467-023-43646-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 11/15/2023] [Indexed: 12/06/2023] Open
Abstract
Phycobilisomes (PBS) are antenna megacomplexes that transfer energy to photosystems II and I in thylakoids. PBS likely evolved from a basic, inefficient form into the predominant hemidiscoidal shape with radiating peripheral rods. However, it has been challenging to test this hypothesis because ancestral species are generally inaccessible. Here we use spectroscopy and cryo-electron microscopy to reveal a structure of a "paddle-shaped" PBS from a thylakoid-free cyanobacterium that likely retains ancestral traits. This PBS lacks rods and specialized ApcD and ApcF subunits, indicating relict characteristics. Other features include linkers connecting two chains of five phycocyanin hexamers (CpcN) and two core subdomains (ApcH), resulting in a paddle-shaped configuration. Energy transfer calculations demonstrate that chains are less efficient than rods. These features may nevertheless have increased light absorption by elongating PBS before multilayered thylakoids with hemidiscoidal PBS evolved. Our results provide insights into the evolution and diversification of light-harvesting strategies before the origin of thylakoids.
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Affiliation(s)
- Han-Wei Jiang
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Hsiang-Yi Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chun-Hsiung Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Cheng-Han Yang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Jui-Tse Ko
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Han-Chen Ho
- Department of Anatomy, Tzu Chi University, Hualien, Taiwan
| | - Ming-Daw Tsai
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Fay-Wei Li
- Boyce Thompson Institute, Ithaca, NY, USA
- Plant Biology Section, Cornell University, Ithaca, NY, USA
| | - Meng-Chiao Ho
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
- Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
- Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan.
| | - Ming-Yang Ho
- Department of Life Science, National Taiwan University, Taipei, Taiwan.
- Institute of Plant Biology, National Taiwan University, Taipei, Taiwan.
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Pessi IS, Popin RV, Durieu B, Lara Y, Tytgat B, Savaglia V, Roncero-Ramos B, Hultman J, Verleyen E, Vyverman W, Wilmotte A. Novel diversity of polar Cyanobacteria revealed by genome-resolved metagenomics. Microb Genom 2023; 9:mgen001056. [PMID: 37417735 PMCID: PMC10438808 DOI: 10.1099/mgen.0.001056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/30/2023] [Indexed: 07/08/2023] Open
Abstract
Benthic microbial mats dominated by Cyanobacteria are important features of polar lakes. Although culture-independent studies have provided important insights into the diversity of polar Cyanobacteria, only a handful of genomes have been sequenced to date. Here, we applied a genome-resolved metagenomics approach to data obtained from Arctic, sub-Antarctic and Antarctic microbial mats. We recovered 37 metagenome-assembled genomes (MAGs) of Cyanobacteria representing 17 distinct species, most of which are only distantly related to genomes that have been sequenced so far. These include (i) lineages that are common in polar microbial mats such as the filamentous taxa Pseudanabaena, Leptolyngbya, Microcoleus/Tychonema and Phormidium; (ii) the less common taxa Crinalium and Chamaesiphon; (iii) an enigmatic Chroococcales lineage only distantly related to Microcystis; and (iv) an early branching lineage in the order Gloeobacterales that is distributed across the cold biosphere, for which we propose the name Candidatus Sivonenia alaskensis. Our results show that genome-resolved metagenomics is a powerful tool for expanding our understanding of the diversity of Cyanobacteria, especially in understudied remote and extreme environments.
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Affiliation(s)
- Igor S. Pessi
- Department of Microbiology, University of Helsinki, Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), Helsinki, Finland
| | - Rafael V. Popin
- Department of Microbiology, University of Helsinki, Helsinki, Finland
| | - Benoit Durieu
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
| | - Yannick Lara
- Early Life Traces & Evolution-Astrobiology, UR-Astrobiology, University of Liège, Liège, Belgium
| | - Bjorn Tytgat
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Valentina Savaglia
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Beatriz Roncero-Ramos
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
- Department of Plant Biology and Ecology, University of Sevilla, Sevilla, Spain
| | - Jenni Hultman
- Department of Microbiology, University of Helsinki, Helsinki, Finland
- Helsinki Institute of Sustainability Science (HELSUS), Helsinki, Finland
- Natural Resources Institute Finland (LUKE), Helsinki, Finland
| | - Elie Verleyen
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Wim Vyverman
- Laboratory of Protistology & Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Annick Wilmotte
- InBioS – Centre for Protein Engineering, University of Liège, Liège, Belgium
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Rockwell NC, Lagarias JC. GUN4 appeared early in cyanobacterial evolution. PNAS NEXUS 2023; 2:pgad131. [PMID: 37152672 PMCID: PMC10156173 DOI: 10.1093/pnasnexus/pgad131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 03/15/2023] [Accepted: 04/06/2023] [Indexed: 05/09/2023]
Abstract
Photosynthesis relies on chlorophylls, which are synthesized via a common tetrapyrrole trunk pathway also leading to heme, vitamin B12, and other pigmented cofactors. The first committed step for chlorophyll biosynthesis is insertion of magnesium into protoporphyrin IX by magnesium chelatase. Magnesium chelatase is composed of H-, I-, and D-subunits, with the tetrapyrrole substrate binding to the H-subunit. This subunit is rapidly inactivated in the presence of substrate, light, and oxygen, so oxygenic photosynthetic organisms require mechanisms to protect magnesium chelatase from similar loss of function. An additional protein, GUN4, binds to the H-subunit and to tetrapyrroles. GUN4 has been proposed to serve this protective role via its ability to bind linear tetrapyrroles (bilins). In the current work, we probe the origins of bilin binding by GUN4 via comparative phylogenetic analysis and biochemical validation of a conserved bilin-binding motif. Based on our results, we propose that bilin-binding GUN4 proteins arose early in cyanobacterial evolution and that this early acquisition represents an ancient adaptation for maintaining chlorophyll biosynthesis in the presence of light and oxygen.
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Molecular Evolution of Far-Red Light-Acclimated Photosystem II. Microorganisms 2022; 10:microorganisms10071270. [PMID: 35888987 PMCID: PMC9325196 DOI: 10.3390/microorganisms10071270] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/17/2022] [Accepted: 06/18/2022] [Indexed: 12/10/2022] Open
Abstract
Cyanobacteria are major contributors to global carbon fixation and primarily use visible light (400-700 nm) to drive oxygenic photosynthesis. When shifted into environments where visible light is attenuated, a small, but highly diverse and widespread number of cyanobacteria can express modified pigments and paralogous versions of photosystem subunits and phycobiliproteins that confer far-red light (FRL) absorbance (700-800 nm), a process termed far-red light photoacclimation, or FaRLiP. During FaRLiP, alternate photosystem II (PSII) subunits enable the complex to bind chlorophylls d and f, which absorb at lower energy than chlorophyll a but still support water oxidation. How the FaRLiP response arose remains poorly studied. Here, we report ancestral sequence reconstruction and structure-based molecular evolutionary studies of the FRL-specific subunits of FRL-PSII. We show that the duplications leading to the origin of two PsbA (D1) paralogs required to make chlorophyll f and to bind chlorophyll d in water-splitting FRL-PSII are likely the first to have occurred prior to the diversification of extant cyanobacteria. These duplications were followed by those leading to alternative PsbC (CP43) and PsbD (D2) subunits, occurring early during the diversification of cyanobacteria, and culminating with those leading to PsbB (CP47) and PsbH paralogs coincident with the radiation of the major groups. We show that the origin of FRL-PSII required the accumulation of a relatively small number of amino acid changes and that the ancestral FRL-PSII likely contained a chlorophyll d molecule in the electron transfer chain, two chlorophyll f molecules in the antenna subunits at equivalent positions, and three chlorophyll a molecules whose site energies were altered. The results suggest a minimal model for engineering far-red light absorbance into plant PSII for biotechnological applications.
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Mallén-Ponce MJ, Huertas MJ, Florencio FJ. Exploring the Diversity of the Thioredoxin Systems in Cyanobacteria. Antioxidants (Basel) 2022; 11:antiox11040654. [PMID: 35453339 PMCID: PMC9025218 DOI: 10.3390/antiox11040654] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 03/25/2022] [Accepted: 03/26/2022] [Indexed: 02/04/2023] Open
Abstract
Cyanobacteria evolved the ability to perform oxygenic photosynthesis using light energy to reduce CO2 from electrons extracted from water and form nutrients. These organisms also developed light-dependent redox regulation through the Trx system, formed by thioredoxins (Trxs) and thioredoxin reductases (TRs). Trxs are thiol-disulfide oxidoreductases that serve as reducing substrates for target enzymes involved in numerous processes such as photosynthetic CO2 fixation and stress responses. We focus on the evolutionary diversity of Trx systems in cyanobacteria and discuss their phylogenetic relationships. The study shows that most cyanobacteria contain at least one copy of each identified Trx, and TrxA is the only one present in all genomes analyzed. Ferredoxin thioredoxin reductase (FTR) is present in all groups except Gloeobacter and Prochlorococcus, where there is a ferredoxin flavin-thioredoxin reductase (FFTR). Our data suggest that both TRs may have coexisted in ancestral cyanobacteria together with other evolutionarily related proteins such as NTRC or DDOR, probably used against oxidative stress. Phylogenetic studies indicate that they have different evolutionary histories. As cyanobacteria diversified to occupy new habitats, some of these proteins were gradually lost in some groups. Finally, we also review the physiological relevance of redox regulation in cyanobacteria through the study of target enzymes.
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Affiliation(s)
- Manuel J. Mallén-Ponce
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
- Correspondence: (M.J.M.-P.); (M.J.H.)
| | - María José Huertas
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
- Correspondence: (M.J.M.-P.); (M.J.H.)
| | - Francisco J. Florencio
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Américo Vespucio 49, 41092 Sevilla, Spain;
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Profesor García González s/n, 41012 Sevilla, Spain
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