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Elias E, Brache K, Schäfers J, Croce R. Coloring Outside the Lines: Exploiting Pigment-Protein Synergy for Far-Red Absorption in Plant Light-Harvesting Complexes. J Am Chem Soc 2024; 146:3508-3520. [PMID: 38286009 PMCID: PMC10859958 DOI: 10.1021/jacs.3c13373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 01/11/2024] [Accepted: 01/11/2024] [Indexed: 01/31/2024]
Abstract
Plants are designed to utilize visible light for photosynthesis. Expanding this light absorption toward the far-red could boost growth in low-light conditions and potentially increase crop productivity in dense canopies. A promising strategy is broadening the absorption of antenna complexes to the far-red. In this study, we investigated the capacity of the photosystem I antenna protein Lhca4 to incorporate far-red absorbing chlorophylls d and f and optimize their spectra. We demonstrate that these pigments can successfully bind to Lhca4, with the protein environment further red-shifting the chlorophyll d absorption, markedly extending the absorption range of this complex above 750 nm. Notably, chlorophyll d substitutes the canonical chlorophyll a red-forms, resulting in the most red-shifted emission observed in a plant light-harvesting complex. Using ultrafast spectroscopy, we show that the introduction of these novel chlorophylls does not interfere with the excited state decay or the energy equilibration processes within the complex. The results demonstrate the feasibility of engineering plant antennae to absorb deeper into the far-red region while preserving their functional and structural integrity, paving the way for innovative strategies to enhance photosynthesis.
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Affiliation(s)
- Eduard Elias
- Department of Physics and
Astronomy and Institute for Lasers, Life and Biophotonics, Faculty
of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Katrin Brache
- Department of Physics and
Astronomy and Institute for Lasers, Life and Biophotonics, Faculty
of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Judith Schäfers
- Department of Physics and
Astronomy and Institute for Lasers, Life and Biophotonics, Faculty
of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
| | - Roberta Croce
- Department of Physics and
Astronomy and Institute for Lasers, Life and Biophotonics, Faculty
of Sciences, Vrije Universiteit Amsterdam, de Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
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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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Zhou LJ, Höppner A, Wang YQ, Hou JY, Scheer H, Zhao KH. Crystallographic and biochemical analyses of a far-red allophycocyanin to address the mechanism of the super-red-shift. PHOTOSYNTHESIS RESEARCH 2024:10.1007/s11120-023-01066-2. [PMID: 38182842 DOI: 10.1007/s11120-023-01066-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/03/2023] [Indexed: 01/07/2024]
Abstract
Far-red absorbing allophycocyanins (APC), identified in cyanobacteria capable of FRL photoacclimation (FaRLiP) and low-light photoacclimation (LoLiP), absorb far-red light, functioning in energy transfer as light-harvesting proteins. We report an optimized method to obtain high purity far-red absorbing allophycocyanin B, AP-B2, of Chroococcidiopsis thermalis sp. PCC7203 by synthesis in Escherichia coli and an improved purification protocol. The crystal structure of the trimer, (PCB-ApcD5/PCB-ApcB2)3, has been resolved to 2.8 Å. The main difference to conventional APCs absorbing in the 650-670 nm range is a largely flat chromophore with the co-planarity extending, in particular, from rings BCD to ring A. This effectively extends the conjugation system of PCB and contributes to the super-red-shifted absorption of the α-subunit (λmax = 697 nm). On complexation with the β-subunit, it is even further red-shifted (λmax, absorption = 707 nm, λmax, emission = 721 nm). The relevance of ring A for this shift is supported by mutagenesis data. A variant of the α-subunit, I123M, has been generated that shows an intense FR-band already in the absence of the β-subunit, a possible model is discussed. Two additional mechanisms are known to red-shift the chromophore spectrum: lactam-lactim tautomerism and deprotonation of the chromophore that both mechanisms appear inconsistent with our data, leaving this question unresolved.
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Affiliation(s)
- Li-Juan Zhou
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, The People's Republic of China
| | - Astrid Höppner
- Center for Structural Studies, Heinrich-Heine-Universität, Düsseldorf, Germany
| | - Yi-Qing Wang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, The People's Republic of China
| | - Jian-Yun Hou
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, The People's Republic of China
| | - Hugo Scheer
- Department Biologie I, Universität München, Menzinger Str. 67, 80638, Munich, Germany
| | - Kai-Hong Zhao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, The People's Republic of China.
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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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Gisriel CJ, Bryant DA, Brudvig GW, Cardona T. Molecular diversity and evolution of far-red light-acclimated photosystem I. FRONTIERS IN PLANT SCIENCE 2023; 14:1289199. [PMID: 38053766 PMCID: PMC10694217 DOI: 10.3389/fpls.2023.1289199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/31/2023] [Indexed: 12/07/2023]
Abstract
The need to acclimate to different environmental conditions is central to the evolution of cyanobacteria. Far-red light (FRL) photoacclimation, or FaRLiP, is an acclimation mechanism that enables certain cyanobacteria to use FRL to drive photosynthesis. During this process, a well-defined gene cluster is upregulated, resulting in changes to the photosystems that allow them to absorb FRL to perform photochemistry. Because FaRLiP is widespread, and because it exemplifies cyanobacterial adaptation mechanisms in nature, it is of interest to understand its molecular evolution. Here, we performed a phylogenetic analysis of the photosystem I subunits encoded in the FaRLiP gene cluster and analyzed the available structural data to predict ancestral characteristics of FRL-absorbing photosystem I. The analysis suggests that FRL-specific photosystem I subunits arose relatively late during the evolution of cyanobacteria when compared with some of the FRL-specific subunits of photosystem II, and that the order Nodosilineales, which include strains like Halomicronema hongdechloris and Synechococcus sp. PCC 7335, could have obtained FaRLiP via horizontal gene transfer. We show that the ancestral form of FRL-absorbing photosystem I contained three chlorophyll f-binding sites in the PsaB2 subunit, and a rotated chlorophyll a molecule in the A0B site of the electron transfer chain. Along with our previous study of photosystem II expressed during FaRLiP, these studies describe the molecular evolution of the photosystem complexes encoded by the FaRLiP gene cluster.
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Affiliation(s)
| | - Donald A. Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States
| | - Gary W. Brudvig
- Department of Chemistry, Yale University, New Haven, CT, United States
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Tanai Cardona
- Department of Life Sciences, Imperial College London, London, United Kingdom
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, United Kingdom
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Gisriel CJ, Elias E, Shen G, Soulier NT, Brudvig GW, Croce R, Bryant DA. Structural comparison of allophycocyanin variants reveals the molecular basis for their spectral differences. PHOTOSYNTHESIS RESEARCH 2023:10.1007/s11120-023-01048-4. [PMID: 37773575 DOI: 10.1007/s11120-023-01048-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/05/2023] [Indexed: 10/01/2023]
Abstract
Allophycocyanins are phycobiliproteins that absorb red light and transfer the energy to the reaction centers of oxygenic photosynthesis in cyanobacteria and red algae. Recently, it was shown that some allophycocyanins absorb far-red light and that one subset of these allophycocyanins, comprising subunits from the ApcD4 and ApcB3 subfamilies (FRL-AP), form helical nanotubes. The lowest energy absorbance maximum of the oligomeric ApcD4-ApcB3 complexes occurs at 709 nm, which is unlike allophycocyanin (AP; ApcA-ApcB) and allophycocyanin B (AP-B; ApcD-ApcB) trimers that absorb maximally at ~ 650 nm and ~ 670 nm, respectively. The molecular bases of the different spectra of AP variants are presently unclear. To address this, we structurally compared FRL-AP with AP and AP-B, performed spectroscopic analyses on FRL-AP, and leveraged computational approaches. We show that among AP variants, the α-subunit constrains pyrrole ring A of its phycocyanobilin chromophore to different extents, and the coplanarity of ring A with rings B and C sets a baseline for the absorbance maximum of the chromophore. Upon oligomerization, the α-chromophores of all AP variants exhibit a red shift of the absorbance maximum of ~ 25 to 30 nm and band narrowing. We exclude excitonic coupling in FRL-AP as the basis for this red shift and extend the results to discuss AP and AP-B. Instead, we attribute these spectral changes to a conformational alteration of pyrrole ring D, which becomes more coplanar with rings B and C upon oligomerization. This study expands the molecular understanding of light-harvesting attributes of phycobiliproteins and will aid in designing phycobiliproteins for biotechnological applications.
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Affiliation(s)
| | - Eduard Elias
- Department of Physics and Astronomy and Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam, 1081 HV, Amsterdam, 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
- Department of Biology, University of California San Diego, La Jolla, CA, 92093, 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 Institute for Lasers, Life and Biophotonics, Faculty of Sciences, VU University Amsterdam, 1081 HV, Amsterdam, Netherlands.
| | - Donald A Bryant
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
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