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Communications Biology May 2024Photosynthetic cryptophytes are eukaryotic algae that utilize membrane-embedded chlorophyll a/c binding proteins (CACs) and lumen-localized phycobiliproteins (PBPs) as...
Photosynthetic cryptophytes are eukaryotic algae that utilize membrane-embedded chlorophyll a/c binding proteins (CACs) and lumen-localized phycobiliproteins (PBPs) as their light-harvesting antennae. Cryptophytes go through logarithmic and stationary growth phases, and may adjust their light-harvesting capability according to their particular growth state. How cryptophytes change the type/arrangement of the photosynthetic antenna proteins to regulate their light-harvesting remains unknown. Here we solve four structures of cryptophyte photosystem I (PSI) bound with CACs that show the rearrangement of CACs at different growth phases. We identify a cryptophyte-unique protein, PsaQ, which harbors two chlorophyll molecules. PsaQ specifically binds to the lumenal region of PSI during logarithmic growth phase and may assist the association of PBPs with photosystems and energy transfer from PBPs to photosystems.
Topics: Photosystem I Protein Complex; Cryptophyta; Light-Harvesting Protein Complexes; Chlorophyll; Chlorophyll Binding Proteins; Photosynthesis; Phycobiliproteins
PubMed: 38734819
DOI: 10.1038/s42003-024-06268-5 -
Marine Drugs Apr 2024Red phycoerythrin (R-PE) is a highly valuable protein found in an edible seaweed, . It is used extensively in biotechnological applications due to its strong...
Red phycoerythrin (R-PE) is a highly valuable protein found in an edible seaweed, . It is used extensively in biotechnological applications due to its strong fluorescence and stability in diverse environments. However, the current methods for extracting and purifying R-PE are costly and unsustainable. The aim of the present study was to enhance the financial viability of the process by improving the extraction and purification of R-PE from dried and to further enhance R-PE value by incorporating it into a tandem dye for molecular biology applications. A combination of ultrafiltration, ion exchange chromatography, and gel filtration yielded concentrated (1 mg·mL) R-PE at 99% purity. Using purified PE and Cyanine5 (Cy5), an organic tandem dye, phycoerythrin-Cy5 (PE-Cy5), was subsequently established. In comparison to a commercially available tandem dye, PE-Cy5 exhibited 202.3% stronger fluorescence, rendering it suitable for imaging and analyzes that require high sensitivity, enhanced signal-to-noise ratio, broad dynamic range, or shorter exposure times to minimize potential damage to samples. The techno-economic analysis confirmed the financial feasibility of the innovative technique for the extraction and purification of R-PE and PE-Cy5 production.
Topics: Phycoerythrin; Carbocyanines; Seaweed; Fluorescent Dyes; Chromatography, Ion Exchange; Chromatography, Gel; Ultrafiltration; Rhodophyta; Pigments, Biological; Edible Seaweeds; Porphyra
PubMed: 38786588
DOI: 10.3390/md22050197 -
Nature Communications Dec 2023
PubMed: 38114511
DOI: 10.1038/s41467-023-44394-6 -
ACS Omega Nov 2023The construction of artificial systems for solar energy harvesting is still a challenge. There needs to be a light-harvesting antenna with a broad absorption spectrum...
The construction of artificial systems for solar energy harvesting is still a challenge. There needs to be a light-harvesting antenna with a broad absorption spectrum and then the possibility to transfer harvested energy to the reaction center, converting photons into a storable form of energy. Bioinspired and bioderivative elements may help in achieving this aim. Here, we present an option for light harvesting: a nanobiohybrid of colloidal, semiconductor quantum dots (QDs) and natural photosynthetic antennae assembled on the surface of a carbon nanotube. For that, we used QDs of cadmium telluride and cyanobacterial phycobilisome rods (PBSr) or light-harvesting complex II (LHCII) of higher plants. For this nanobiohybrid, we confirmed composition and organization using infrared spectroscopy, X-ray photoelectron spectroscopy, and high-resolution confocal microscopy. Then, we proved that within such an assembly, there is a resonance energy transfer from QD to PBSr or LHCII. When such a nanobiohybrid was further combined with thylakoids, the energy was transferred to photosynthetic reaction centers and efficiently powered the photosystem I reaction center. The presented construct is proof of a general concept, combining interacting elements on a platform of a nanotube, allowing further variation within assembled elements.
PubMed: 37969970
DOI: 10.1021/acsomega.3c07673 -
Communications Biology Sep 2023The mechanisms of acclimating to a nitrogen-fluctuating environment are necessary for the survival of aquatic cyanobacteria in their natural habitats, but our...
The mechanisms of acclimating to a nitrogen-fluctuating environment are necessary for the survival of aquatic cyanobacteria in their natural habitats, but our understanding is still far from complete. Here, the synthesis of phycobiliprotein is confirmed to be much earlier than that of photosystem components during recovery from nitrogen chlorosis and an unknown protein Ssr1698 is discovered to be involved in this synthetic process. The unknown protein is further identified as a c-type heme oxygenase (cHO) in tetrapyrrole biosynthetic pathway and catalyzes the opening of heme ring to form biliverdin IXα, which is required for phycobilin production and ensuing phycobiliprotein synthesis. In addition, the cHO-dependent phycobiliprotein is found to be vital for the growth of cyanobacterial cells during chlorosis and regreening through its nitrogen-storage and light-harvesting functions, respectively. Collectively, the cHO expressed preferentially during recovery from nitrogen chlorosis is identified in photosynthetic organisms and the dual function of this enzyme-dependent phycobiliprotein is proposed to be an important mechanism for acclimation of aquatic cyanobacteria to a nitrogen-fluctuating environment.
Topics: Humans; Heme Oxygenase (Decyclizing); Cyanobacteria; Acclimatization; Anemia, Hypochromic; Nitrogen; Phycobiliproteins
PubMed: 37714932
DOI: 10.1038/s42003-023-05315-x -
Communications Biology Nov 2023Photosynthetic organisms adapt to changing light conditions by manipulating their light harvesting complexes. Biophysical, biochemical, physiological and genetic aspects...
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.
Topics: Phycobilisomes; Porphyridium; Cryoelectron Microscopy; Rhodophyta; Acclimatization
PubMed: 38012412
DOI: 10.1038/s42003-023-05586-4 -
Nature Communications Jul 2023Phycobilisomes (PBS) are the major light harvesting complexes of photosynthesis in the cyanobacteria and red algae. CpcL-PBS is a type of small PBS in cyanobacteria that...
Phycobilisomes (PBS) are the major light harvesting complexes of photosynthesis in the cyanobacteria and red algae. CpcL-PBS is a type of small PBS in cyanobacteria that transfers energy directly to photosystem I without the core structure. Here we report the cryo-EM structure of the CpcL-PBS from the cyanobacterium Synechocystis sp. PCC 6803 at 2.6-Å resolution. The structure shows the CpcD domain of ferredoxin: NADP oxidoreductase is located at the distal end of CpcL-PBS, responsible for its attachment to PBS. With the evidence of ultrafast transient absorption and fluorescence spectroscopy, the roles of individual bilins in energy transfer are revealed. The bilin β located near photosystem I has an enhanced planarity and is the red-bilin responsible for the direct energy transfer to photosystem I.
Topics: Phycobilisomes; Photosystem I Protein Complex; Cryoelectron Microscopy; Synechocystis; Spectrometry, Fluorescence; Energy Transfer; Bacterial Proteins
PubMed: 37407580
DOI: 10.1038/s41467-023-39689-7 -
Nutrients Jun 2024, commonly known as , is a photosynthetic filamentous cyanobacterium (blue-green microalga) that has been utilized as a food source since ancient times. More recently,... (Review)
Review
, commonly known as , is a photosynthetic filamentous cyanobacterium (blue-green microalga) that has been utilized as a food source since ancient times. More recently, it has gained significant popularity as a dietary supplement due to its rich content of micro- and macro-nutrients. Of particular interest is a water soluble phycobiliprotein derived from known as phycocyanin C (C-PC), which stands out as the most abundant protein in this cyanobacterium. C-PC is a fluorescent protein, with its chromophore represented by the tetrapyrrole molecule phycocyanobilin B (PCB-B). While C-PC is commonly employed in food for its coloring properties, it also serves as the molecular basis for numerous nutraceutical features associated with . Indeed, the comprehensive C-PC, and to some extent, the isolated PCB-B, has been linked to various health-promoting effects. These benefits encompass conditions triggered by oxidative stress, inflammation, and other pathological conditions. The present review focuses on the bio-pharmacological properties of these molecules, positioning them as promising agents for potential new applications in the expanding nutraceutical market.
Topics: Dietary Supplements; Spirulina; Phycocyanin; Humans; Phycobilins; Phycobiliproteins; Oxidative Stress
PubMed: 38892686
DOI: 10.3390/nu16111752 -
Environmental Monitoring and Assessment Aug 2023Worldwide, there has been an increase in the presence of potentially toxic cyanobacterial blooms in drinking water sources and within drinking water treatment plants...
Worldwide, there has been an increase in the presence of potentially toxic cyanobacterial blooms in drinking water sources and within drinking water treatment plants (DWTPs). The objective of this study is to validate the use of in situ probes for the detection and management of cyanobacterial breakthrough in high and low-risk DWTPs. In situ phycocyanin YSI EXO2 probes were devised for remote control and data logging to monitor the cyanobacteria in raw, clarified, filtered, and treated water in three full-scale DWTPs. An additional probe was installed inside the sludge holding tank to measure the water quality of the surface of the sludge storage tank in a high-risk DWTP. Simultaneous grab samplings were carried out for taxonomic cell counts and toxin analysis. A total of 23, 9, and 4 field visits were conducted at the three DWTPs. Phycocyanin readings showed a 93-fold fluctuation within 24 h in the raw water of the high cyanobacterial risk plant, with higher phycocyanin levels during the afternoon period. These data provide new information on the limitations of weekly or daily grab sampling. Also, different moving averages for the phycocyanin probe readings can be used to improve the interpretation of phycocyanin signal trends. The in situ probe successfully detected high cyanobacterial biovolumes entering the clarification process in the high-risk plant. Grab sampling results revealed high cyanobacterial biovolumes in the sludge for both high and low-risk plants.
Topics: Phycocyanin; Drinking Water; Sewage; Environmental Monitoring; Cyanobacteria
PubMed: 37589790
DOI: 10.1007/s10661-023-11657-0 -
Archives of Razi Institute Dec 2023The present study was performed to evaluate the effect of phycoerythrin (PE) treatment extracted from Nostoc sp. on the shelf-life extension of the Nile Tilapia ()...
The present study was performed to evaluate the effect of phycoerythrin (PE) treatment extracted from Nostoc sp. on the shelf-life extension of the Nile Tilapia () fillet at 4°C and 8°C. After extraction and purification of pigment in BG-110 medium, the pigment PE was extracted and purified with 56% ammonium sulfate followed by dialysis. After that, the effect of pigment on and were investigated. The fillet samples were immersed in pigment solution, and their physicochemical, microbiological and sensory properties were examined. The results showed that the concentration and purity of the pigments increased after the dialysis. The results from performed chemical tests and total number of living mesophilic bacteria, psychrotrophic bacteria, coagulase positive, and coliform bacteria of the samples compared to the blank sample showed that sample treated with algae extracts were able to control the increase in these parameters. In these tests, the highest levels belonged to Nile Tilapia fillet sample Nile Tilapia fillet coated with PE solution at a temperature 8°C and the lowest amount was observed with fillet coated with PE solution at a temperature of 4˚C (P≤0.05). The results of sensory evaluation showed that the highest score of taste, texture, color, and total acceptance were observed for Nile Tilapia fillet coated with PE solution at temperature 8°C. In conclusion, the extract pigments from sp. has strong antimicrobial activity and can maintain the quality parameters for controlling of spoilage bacteria and extend the shelf-life of .
Topics: Animals; Cichlids; Phycoerythrin; Staphylococcus aureus; Nostoc; Refrigeration; Escherichia coli; Food Storage; Food Preservation; Seafood; Anti-Infective Agents
PubMed: 38828175
DOI: 10.32592/ARI.2023.78.6.1811