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Gisriel CJ, Shen G, Brudvig GW, Bryant DA. Structure of the antenna complex expressed during far-red light photoacclimation in Synechococcus sp. PCC 7335. J Biol Chem 2024; 300:105590. [PMID: 38141759 PMCID: PMC10810746 DOI: 10.1016/j.jbc.2023.105590] [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: 10/22/2023] [Revised: 11/28/2023] [Accepted: 12/12/2023] [Indexed: 12/25/2023] Open
Abstract
Far-red light photoacclimation, or FaRLiP, is a facultative response exhibited by some cyanobacteria that allows them to absorb and utilize lower energy light (700-800 nm) than the wavelengths typically used for oxygenic photosynthesis (400-700 nm). During this process, three essential components of the photosynthetic apparatus are altered: photosystem I, photosystem II, and the phycobilisome. In all three cases, at least some of the chromophores found in these pigment-protein complexes are replaced by chromophores that have red-shifted absorbance relative to the analogous complexes produced in visible light. Recent structural and spectroscopic studies have elucidated important features of the two photosystems when altered to absorb and utilize far-red light, but much less is understood about the modified phycobiliproteins made during FaRLiP. We used single-particle, cryo-EM to determine the molecular structure of a phycobiliprotein core complex comprising allophycocyanin variants that absorb far-red light during FaRLiP in the marine cyanobacterium Synechococcus sp. PCC 7335. The structure reveals the arrangement of the numerous red-shifted allophycocyanin variants and the probable locations of the chromophores that serve as the terminal emitters in this complex. It also suggests how energy is transferred to the photosystem II complexes produced during FaRLiP. The structure additionally allows comparisons with other previously studied allophycocyanins to gain insights into how phycocyanobilin chromophores can be tuned to absorb far-red light. These studies provide new insights into how far-red light is harvested and utilized during FaRLiP, a widespread cyanobacterial photoacclimation mechanism.
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Affiliation(s)
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Gary W Brudvig
- Department of Chemistry, Yale University, New Haven, Connecticut, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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Gupta A, Pandey P, Gupta R, Tiwari S, Singh SP. Responding to light signals: a comprehensive update on photomorphogenesis in cyanobacteria. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2023; 29:1915-1930. [PMID: 38222287 PMCID: PMC10784256 DOI: 10.1007/s12298-023-01386-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 01/16/2024]
Abstract
Cyanobacteria are ancestors of chloroplast and perform oxygen-evolving photosynthesis similar to higher plants and algae. However, an obligatory requirement of photons for their growth results in the exposure of cyanobacteria to varying light conditions. Therefore, the light environment could act as a signal to drive the developmental processes, in addition to photosynthesis, in cyanobacteria. These Gram-negative prokaryotes exhibit characteristic light-dependent developmental processes that maximize their fitness and resource utilization. The development occurring in response to radiance (photomorphogenesis) involves fine-tuning cellular physiology, morphology and metabolism. The best-studied example of cyanobacterial photomorphogenesis is chromatic acclimation (CA), which allows a selected number of cyanobacteria to tailor their light-harvesting antenna called phycobilisome (PBS). The tailoring of PBS under existing wavelengths and abundance of light gives an advantage to cyanobacteria over another photoautotroph. In this work, we will provide a comprehensive update on light-sensing, molecular signaling and signal cascades found in cyanobacteria. We also include recent developments made in other aspects of CA, such as mechanistic insights into changes in the size and shape of cells, filaments and carboxysomes.
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Affiliation(s)
- Anjali Gupta
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, UP 221005 India
| | - Priyul Pandey
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, UP 221005 India
| | - Rinkesh Gupta
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, UP 221005 India
| | - Sapna Tiwari
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, UP 221005 India
| | - Shailendra Pratap Singh
- Department of Botany, Centre of Advanced Study in Botany, Institute of Science, Banaras Hindu University, Varanasi, UP 221005 India
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Dodson EJ, Ma J, Suissa Szlejf M, Maroudas-Sklare N, Paltiel Y, Adir N, Sun S, Sui SF, Keren N. The structural basis for light acclimation in phycobilisome light harvesting systems systems in Porphyridium purpureum. Commun Biol 2023; 6:1210. [PMID: 38012412 PMCID: PMC10682464 DOI: 10.1038/s42003-023-05586-4] [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: 03/30/2023] [Accepted: 11/14/2023] [Indexed: 11/29/2023] Open
Abstract
Photosynthetic organisms adapt to changing light conditions by manipulating their light harvesting complexes. Biophysical, biochemical, physiological and genetic aspects of these processes are studied extensively. The structural basis for these studies is lacking. In this study we address this gap in knowledge by focusing on phycobilisomes (PBS), which are large structures found in cyanobacteria and red algae. In this study we focus on the phycobilisomes (PBS), which are large structures found in cyanobacteria and red algae. Specifically, we examine red algae (Porphyridium purpureum) grown under a low light intensity (LL) and a medium light intensity (ML). Using cryo-electron microscopy, we resolve the structure of ML-PBS and compare it to the LL-PBS structure. The ML-PBS is 13.6 MDa, while the LL-PBS is larger (14.7 MDa). The LL-PBS structure have a higher number of closely coupled chromophore pairs, potentially the source of the red shifted fluorescence emission from LL-PBS. Interestingly, these differences do not significantly affect fluorescence kinetics parameters. This indicates that PBS systems can maintain similar fluorescence quantum yields despite an increase in LL-PBS chromophore numbers. These findings provide a structural basis to the processes by which photosynthetic organisms adapt to changing light conditions.
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Affiliation(s)
- Emma Joy Dodson
- Department of Plant and Environmental Science, The Alexander Silberman Institute of Life Sciences, The Hebrew University in Jerusalem, Jerusalem, Israel
| | - Jianfei Ma
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Maayan Suissa Szlejf
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 32000, Haifa, Israel
| | - Naama Maroudas-Sklare
- Department of Applied Physics, The Hebrew University in Jerusalem, Jerusalem, Israel
| | - Yossi Paltiel
- Department of Applied Physics, The Hebrew University in Jerusalem, Jerusalem, Israel
| | - Noam Adir
- Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, 32000, Haifa, Israel
| | - Shan Sun
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Sen-Fang Sui
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structures, Beijing Advanced Innovation Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- School of Life Sciences, Cryo-EM Center, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Nir Keren
- Department of Plant and Environmental Science, The Alexander Silberman Institute of Life Sciences, The Hebrew University in Jerusalem, Jerusalem, Israel.
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Chen M, Sawicki A, Wang F. Modeling the Characteristic Residues of Chlorophyll f Synthase (ChlF) from Halomicronema hongdechloris to Determine Its Reaction Mechanism. Microorganisms 2023; 11:2305. [PMID: 37764149 PMCID: PMC10535343 DOI: 10.3390/microorganisms11092305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/07/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Photosystem II (PSII) is a quinone-utilizing photosynthetic system that converts light energy into chemical energy and catalyzes water splitting. PsbA (D1) and PsbD (D2) are the core subunits of the reaction center that provide most of the ligands to redox-active cofactors and exhibit photooxidoreductase activities that convert quinone and water into quinol and dioxygen. The performed analysis explored the putative uncoupled electron transfer pathways surrounding P680+ induced by far-red light (FRL) based on photosystem II (PSII) complexes containing substituted D1 subunits in Halomicronema hongdechloris. Chlorophyll f-synthase (ChlF) is a D1 protein paralog. Modeling PSII-ChlF complexes determined several key protein motifs of ChlF. The PSII complexes included a dysfunctional Mn4CaO5 cluster where ChlF replaced the D1 protein. We propose the mechanism of chlorophyll f synthesis from chlorophyll a via free radical chemistry in an oxygenated environment created by over-excited pheophytin a and an inactive water splitting reaction owing to an uncoupled Mn4CaO5 cluster in PSII-ChlF complexes. The role of ChlF in the formation of an inactive PSII reaction center is under debate, and putative mechanisms of chlorophyll f biosynthesis are discussed.
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Affiliation(s)
- Min Chen
- School of Life and Environmental Sciences, University of Sydney, Sydney, NSW 2006, Australia
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Gisriel CJ, Elias E, Shen G, Soulier NT, Flesher DA, Gunner MR, Brudvig GW, Croce R, Bryant DA. Helical allophycocyanin nanotubes absorb far-red light in a thermophilic cyanobacterium. SCIENCE ADVANCES 2023; 9:eadg0251. [PMID: 36961897 PMCID: PMC10038336 DOI: 10.1126/sciadv.adg0251] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
To compete in certain low-light environments, some cyanobacteria express a paralog of the light-harvesting phycobiliprotein, allophycocyanin (AP), that strongly absorbs far-red light (FRL). Using cryo-electron microscopy and time-resolved absorption spectroscopy, we reveal the structure-function relationship of this FRL-absorbing AP complex (FRL-AP) that is expressed during acclimation to low light and that likely associates with chlorophyll a-containing photosystem I. FRL-AP assembles as helical nanotubes rather than typical toroids due to alterations of the domain geometry within each subunit. Spectroscopic characterization suggests that FRL-AP nanotubes are somewhat inefficient antenna; however, the enhanced ability to harvest FRL when visible light is severely attenuated represents a beneficial trade-off. The results expand the known diversity of light-harvesting proteins in nature and exemplify how biological plasticity is achieved by balancing resource accessibility with efficiency.
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Affiliation(s)
| | - Eduard Elias
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Gaozhong Shen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Nathan T. Soulier
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - David A. Flesher
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - M. R. Gunner
- Department of Physics, City College of New York, New York, NY 10031, USA
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, CT 06520, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Roberta Croce
- Department of Physics and Astronomy, and LaserLaB Amsterdam, Vrije Universiteit Amsterdam, De Boelelaan 1081, 1081 HV, Amsterdam, The Netherlands
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
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