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Proceedings of the National Academy of... Mar 2021Marine cyanobacteria owe their ubiquity in part to the wide pigment diversity of their light-harvesting complexes. In open ocean waters, cells predominantly possess...
Marine cyanobacteria owe their ubiquity in part to the wide pigment diversity of their light-harvesting complexes. In open ocean waters, cells predominantly possess sophisticated antennae with rods composed of phycocyanin and two types of phycoerythrins (PEI and PEII). Some strains are specialized for harvesting either green or blue light, while others can dynamically modify their light absorption spectrum to match the dominant ambient color. This process, called type IV chromatic acclimation (CA4), has been linked to the presence of a small genomic island occurring in two configurations (CA4-A and CA4-B). While the CA4-A process has been partially characterized, the CA4-B process has remained an enigma. Here we characterize the function of two members of the phycobilin lyase E/F clan, MpeW and MpeQ, in sp. strain A15-62 and demonstrate their critical role in CA4-B. While MpeW, encoded in the CA4-B island and up-regulated in green light, attaches the green light-absorbing chromophore phycoerythrobilin to cysteine-83 of the PEII α-subunit in green light, MpeQ binds phycoerythrobilin and isomerizes it into the blue light-absorbing phycourobilin at the same site in blue light, reversing the relationship of MpeZ and MpeY in the CA4-A strain RS9916. Our data thus reveal key molecular differences between the two types of chromatic acclimaters, both highly abundant but occupying distinct complementary ecological niches in the ocean. They also support an evolutionary scenario whereby CA4-B island acquisition allowed former blue light specialists to become chromatic acclimaters, while former green light specialists would have acquired this capacity by gaining a CA4-A island.
Topics: Acclimatization; Aquatic Organisms; Bacterial Proteins; Cloning, Molecular; Escherichia coli; Gene Expression Regulation, Bacterial; Genetic Complementation Test; Genetic Vectors; Genomic Islands; Light; Light-Harvesting Protein Complexes; Lyases; Phycobilins; Phycocyanin; Phycoerythrin; Phylogeny; Pigments, Biological; Protein Subunits; Recombinant Proteins; Synechococcus; Urobilin
PubMed: 33627406
DOI: 10.1073/pnas.2019715118 -
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 -
Biochimica Et Biophysica Acta.... Apr 2019In this study, we use ultrafast time-resolved absorption and fluorescence spectroscopies to examine A. marina phycobilisomes isolated from cells grown under light of...
In this study, we use ultrafast time-resolved absorption and fluorescence spectroscopies to examine A. marina phycobilisomes isolated from cells grown under light of different intensities and spectral regimes. Investigations were performed at room temperature and at 77 K. The study demonstrates that if complexes are stabilized by high phosphate (900 mM) buffer, there are no differences between them in temporal and spectral properties of fluorescence. However, when the complexes are allowed to disassemble into trimers in low phosphate (50 mM) buffer, differences are clearly observed. The fluorescence properties of intact or disassembled phycobilisomes from cells grown in low intensity white light are unresponsive to variation in phosphate concentration. This antenna complex was further studied in detail with application of femtosecond time-resolved absorption at room temperature. Combined spectroscopic and kinetic analysis of time-resolved fluorescence and absorption data of this antenna allowed us to identify spectrally different forms of phycocyanobilins and to propose a simplified model of how they could be distributed within the phycobilisome structure.
Topics: Bacterial Proteins; Cyanobacteria; Phycobilins; Phycobilisomes; Phycocyanin; Spectrometry, Fluorescence
PubMed: 30703363
DOI: 10.1016/j.bbabio.2019.01.002 -
Microbial Cell Factories Mar 2019Phycobiliproteins (PBPs) are light-harvesting protein found in cyanobacteria, red algae and the cryptomonads. They have been widely used as fluorescent labels in...
BACKGROUND
Phycobiliproteins (PBPs) are light-harvesting protein found in cyanobacteria, red algae and the cryptomonads. They have been widely used as fluorescent labels in cytometry and immunofluorescence analysis. A number of PBPs has been produced in metabolically engineered Escherichia coli. However, the recombinant PBPs are incompletely chromophorylated, and the underlying mechanisms are not clear.
RESULTS AND DISCUSSION
In this work, a pathway for SLA-PEB [a fusion protein of streptavidin and allophycocyanin that covalently binds phycoerythrobilin (PEB)] biosynthesis in E. coli was constructed using a single-expression plasmid strategy. Compared with a previous E. coli strain transformed with dual plasmids, the E. coli strain transformed with a single plasmid showed increased plasmid stability and produced SLA-PEB with a higher chromophorylation ratio. To achieve full chromophorylation of SLA-PEB, directed evolution was employed to improve the catalytic performance of lyase CpcS. In addition, the catalytic abilities of heme oxygenases from different cyanobacteria were investigated based on biliverdin IXα and PEB accumulation. Upregulation of the heme biosynthetic pathway genes was also carried out to increase heme availability and PEB biosynthesis in E. coli. Fed-batch fermentation was conducted for the strain V5ALD, which produced recombinant SLA-PEB with a chromophorylation ratio of 96.7%.
CONCLUSION
In addition to reporting the highest chromophorylation ratio of recombinant PBPs to date, this work demonstrated strategies for improving the chromophorylation of recombinant protein, especially biliprotein with heme, or its derivatives as a prosthetic group.
Topics: Cyanobacteria; Escherichia coli; Metabolic Engineering; Phycobilins; Phycobiliproteins; Phycocyanin; Phycoerythrin; Plasmids; Recombinant Fusion Proteins; Streptavidin
PubMed: 30894191
DOI: 10.1186/s12934-019-1100-6 -
The Journal of Biological Chemistry Nov 1991An enzyme extract from the phycocyanin-containing unicellular rhodophyte, Cyanidium caldarium, reductively transforms biliverdin IX alpha to phycocyanobilin, the...
An enzyme extract from the phycocyanin-containing unicellular rhodophyte, Cyanidium caldarium, reductively transforms biliverdin IX alpha to phycocyanobilin, the chromophore of phycocyanin, in the presence of NADPH. Unpurified cell extract forms both 3(E)-phycocyanobilin, which is identical to the major pigment that is released from phycocyanin by methanolysis, and 3(Z)-phycocyanobilin, which is obtained as a minor methanolysis product. After removal of low molecular weight material from the cell extract, only 3(Z)-phycocyanobilin is formed. 3(E)-Phycocyanobilin formation from biliverdin IX alpha, and the ability to isomerize 3(Z)-phycocyanobilin to 3(E)-phycocyanobilin, are reconstituted by the addition of glutathione to the incubation mixture. Partially purified protein fractions derived from the initial enzyme extract form 3(Z)-phycocyanobilin plus two additional, violet colored bilins, upon incubation with NADPH and biliverdin IX alpha. Further purified protein fractions produce only the violet colored bilins from biliverdin IX alpha. One of these bilins was identified as 3(Z)-phycoerythrobilin by comparative spectrophotometry, reverse-phase high pressure liquid chromatography, and 1H NMR spectroscopy. A C. caldarium protein fraction catalyzes the conversion of 3(Z)-phycoerythrobilin to 3(Z)-phycocyanobilin. This fraction also catalyzes the conversion of 3(E)-phycoerythrobilin to 3(E)-phycocyanobilin. The conversion of phycoerythrobilins to phycocyanobilins requires neither biliverdin nor NADPH. The synthesis of phycoerythrobilin and its conversion to phycocyanobilin by extracts of C. caldarium, a species that does not contain phycoerythrin, indicates that phycoerythrobilin is a biosynthetic precursor to phycocyanobilin. The enzymatic conversion of the ethylidine group from the Z to the E configuration suggests that the E-isomer is the precursor to the protein-bound chromophore.
Topics: Biliverdine; Chromatography, High Pressure Liquid; Glutathione; Isomerism; Light-Harvesting Protein Complexes; Magnetic Resonance Spectroscopy; Molecular Structure; Phycobilins; Phycocyanin; Plant Proteins; Pyrroles; Rhodophyta; Spectrophotometry; Tetrapyrroles
PubMed: 1939256
DOI: No ID Found -
International Journal of Molecular... Aug 2018The objective of the present study was to identify peptides, based on active components of the red algae seaweed Pyropia yezoensis, able to inhibit the generation of...
The objective of the present study was to identify peptides, based on active components of the red algae seaweed Pyropia yezoensis, able to inhibit the generation of reactive oxygen species (ROS), which is associated with aging and oxidative activities. Phycobilin, specific to red algae, covalently binds with water‑soluble proteins. There are three types of pigment bound proteins, known as phycobiliproteins (PBPs): Phycoerythrin (PE), phycocyanin (PC) and allophycocyanin (APC). In the present study, PBPs reported previously to have antioxidant activities in P. yezoensis were identified and, based on these data, several peptides were synthesized (PBP 1‑13) and their inhibition of ROS generation was examined. The existence of PBPs of each type, PE, PC and APC, was established in P. yezoensis and all were analyzed. In addition, PBP 1‑2 and 7‑9 peptides from PE were synthesized and showed antioxidant activities in HepG2 cells. In HepG2 cells, treatment with PBP2 reduced hydrogen peroxide‑mediated oxidative stress and restored the expression of superoxide dismutase (SOD). Furthermore, phosphorylated nuclear factor erythroid‑derived 2‑like 2 (Nrf2) was elevated by PBP2 treatment. Overall, these results suggested that Nrf2-SOD pathways may be involved in the PBP2‑mediated antioxidant effects. Therefore, from the investigations of P. yezoensis, several candidate peptides were identified with promising antioxidant and, potentially, anti‑aging properties.
Topics: Antioxidants; Hep G2 Cells; Humans; Oxidative Stress; Peptides; Phycobiliproteins; Reactive Oxygen Species; Rhodophyta; Superoxide Dismutase
PubMed: 29717771
DOI: 10.3892/ijmm.2018.3650 -
Nature Communications May 2017Marine chromophoric dissolved organic matter (CDOM) and its related fluorescent components (FDOM), which are widely distributed but highly photobleached in the surface...
Marine chromophoric dissolved organic matter (CDOM) and its related fluorescent components (FDOM), which are widely distributed but highly photobleached in the surface ocean, are critical in regulating light attenuation in the ocean. However, the origins of marine FDOM are still under investigation. Here we show that cultured picocyanobacteria, Synechococcus and Prochlorococcus, release FDOM that closely match the typical fluorescent signals found in oceanic environments. Picocyanobacterial FDOM also shows comparable apparent fluorescent quantum yields and undergoes similar photo-degradation behaviour when compared with deep-ocean FDOM, further strengthening the similarity between them. Ultrahigh-resolution mass spectrometry (MS) and nuclear magnetic resonance spectroscopy reveal abundant nitrogen-containing compounds in Synechococcus DOM, which may originate from degradation products of the fluorescent phycobilin pigments. Given the importance of picocyanobacteria in the global carbon cycle, our results indicate that picocyanobacteria are likely to be important sources of marine autochthonous FDOM, which may accumulate in the deep ocean.
Topics: Aquatic Organisms; Carbon Cycle; Fluorescent Dyes; Magnetic Resonance Spectroscopy; Nitrogen; Oceans and Seas; Photobleaching; Phycobilins; Prochlorococcus; Seawater; Synechococcus
PubMed: 28513605
DOI: 10.1038/ncomms15284 -
Photosynthesis Research Jun 2020The crystal structure of phycocyanin (pr-PC) isolated from Phormidium rubidum A09DM (P. rubidum) is described at a resolution of 1.17 Å. Electron density maps derived...
The crystal structure of phycocyanin (pr-PC) isolated from Phormidium rubidum A09DM (P. rubidum) is described at a resolution of 1.17 Å. Electron density maps derived from crystallographic data showed many clear differences in amino acid sequences when compared with the previously obtained gene-derived sequences. The differences were found in 57 positions (30 in α-subunit and 27 in β-subunit of pr-PC), in which all residues except one (β145Arg) are not interacting with the three phycocyanobilin chromophores. Highly purified pr-PC was then sequenced by mass spectrometry (MS) using LC-MS/MS. The MS data were analyzed using two independent proteomic search engines. As a result of this analysis, complete agreement between the polypeptide sequences and the electron density maps was obtained. We attribute the difference to multiple genes in the bacterium encoding the phycocyanin apoproteins and that the gene sequencing sequenced the wrong ones. We are not implying that protein sequencing by mass spectrometry is more accurate than that of gene sequencing. The final 1.17 Å structure of pr-PC allows the chromophore interactions with the protein to be described with high accuracy.
Topics: Amino Acid Sequence; Chromatography, Liquid; Crystallography; Phormidium; Phycobilins; Phycocyanin; Proteomics; Sequence Analysis, Protein; Tandem Mass Spectrometry
PubMed: 32303893
DOI: 10.1007/s11120-020-00746-7 -
Proceedings of the National Academy of... Dec 2004Directed evolution of a cyanobacterial phytochrome was undertaken to elucidate the structural basis of its light sensory activity by remodeling the chemical environment...
Directed evolution of a cyanobacterial phytochrome was undertaken to elucidate the structural basis of its light sensory activity by remodeling the chemical environment of its linear tetrapyrrole prosthetic group. In addition to identifying a small region of the apoprotein critical for maintaining phytochrome's native spectroscopic properties, our studies revealed a tyrosine-to-histidine mutation that transformed phytochrome into an intensely red fluorescent biliprotein. This tyrosine is conserved in all members of the phytochrome superfamily, implicating direct participation in the primary photoprocess of phytochromes. Fluorescent phytochrome mutants also hold great promise to expand the present repertoire of genetically encoded fluorescent proteins into the near infrared.
Topics: Bacterial Proteins; Color; Evolution, Molecular; Fluorescence; Infrared Rays; Molecular Structure; Multigene Family; Mutation; Photoreceptors, Microbial; Phycobilins; Phycocyanin; Phytochrome; Protein Kinases; Pyrroles; Spectrometry, Fluorescence; Synechocystis; Tetrapyrroles
PubMed: 15548612
DOI: 10.1073/pnas.0407645101 -
The Journal of General Physiology Mar 1950A polarographic oxygen determination, with tissue in direct contact with a stationary platinum electrode, has been used to measure the photosynthetic response of marine...
A polarographic oxygen determination, with tissue in direct contact with a stationary platinum electrode, has been used to measure the photosynthetic response of marine algae. These were exposed to monochromatic light, of equal energy, at some 35 points through the visible spectrum (derived from a monochromator). Ulva and Monostroma (green algae) show action spectra which correspond very closely to their absorption spectra. Coilodesme (a brown alga) shows almost as good correspondence, including the spectral region absorbed by the carotenoid, fucoxanthin. In green and brown algae, light absorbed by both chlorophyll and carotenoids seems photosynthetically effective, although some inactive absorption by carotenoids is indicated. Action spectra for a wide variety of red algae, however, show marked deviations from their corresponding absorption spectra. The photosynthetic rates are high in the spectral regions absorbed by the water-soluble "phycobilin" pigments (phycoerythrin and phycocyanin), while the light absorbed by chlorophyll and carotenoids is poorly utilized for oxygen production. In red algae containing chiefly phycoerythrin, the action spectrum closely resembles that of the water-extracted pigment, with peaks corresponding to its absorption maxima (495, 540, and 565 mmicro). Such algae include Delesseria, Schizymenia, and Porphyrella. In the genus Porphyra, there is a series P. nereocystis, P. naiadum, and P. perforata, with increasingly more phycocyanin and less phycoerythrin: the action spectra reflect this, with increasing activity in the orange-red region (600 to 640 mmicro) where phycocyanin absorbs. In all these red algae, photosynthesis is almost minimal at 435 mmicro and 675 mmicro, where chlorophyll shows maximum absorption. Although the chlorophylls (and carotenoids) are present in quantities comparable to the green algae, their function is apparently not that of a primary light absorber; this role is taken over by the phycobilins. In this respect the red algae (Rhodophyta) appear unique among photosynthetic plants.
Topics: Chlorophyll; Eukaryota; Light; Oxygen; Photosynthesis; Xanthophylls
PubMed: 15406376
DOI: 10.1085/jgp.33.4.389