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The Journal of Physical Chemistry. B May 2023Aquatic photosynthetic organisms evolved to use a variety of light frequencies to perform photosynthesis. Phycobiliprotein phycocyanin 645 (PC645) is a light-harvesting...
Aquatic photosynthetic organisms evolved to use a variety of light frequencies to perform photosynthesis. Phycobiliprotein phycocyanin 645 (PC645) is a light-harvesting complex in cryptophyte algae able to transfer the absorbed green solar light to other antennas with over 99% efficiency. The infrared signatures of the phycobilin pigments embedded in PC645 are difficult to access and could provide useful information to understand the mechanism behind the high efficiency of energy transfer in PC645. We use visible-pump IR-probe and two-dimensional electronic vibrational spectroscopy to study the dynamical evolution and assign the fingerprint mid-infrared signatures to each pigment in PC645. Here, we report the pigment-specific vibrational markers that enable us to track the spatial flow of excitation energy between the phycobilin pigment pairs. We speculate that two high-frequency modes (1588 and 1596 cm) are involved in the vibronic coupling leading to fast (
Topics: Phycobilins; Phycocyanin; Phycobiliproteins; Photosynthesis
PubMed: 37192324
DOI: 10.1021/acs.jpcb.3c01352 -
The Journal of Biological Chemistry Aug 1992The unicellular red alga, Cyanidium caldarium, synthesizes phycocyanobilin from protoheme via biliverdin IX alpha. In vitro transformation of protoheme to biliverdin IX... (Comparative Study)
Comparative Study
The unicellular red alga, Cyanidium caldarium, synthesizes phycocyanobilin from protoheme via biliverdin IX alpha. In vitro transformation of protoheme to biliverdin IX alpha and biliverdin IX alpha to phycobilins were previously shown to require NADPH, ferredoxin, and ferredoxin-NADP+ reductase, as well as specific heme oxygenase and phycobilin formation enzymes. The role of NADPH in these reactions was investigated in this study. The C. caldarium enzymatic activities that catalyze biliverdin IX alpha formation from protoheme, and phycobilin formation from biliverdin IX alpha, were partially purified by differential (NH4)2SO4 precipitation. The enzyme fractions, when supplemented with a light-driven ferredoxin-reducing photosystem I fraction derived from spinach leaves, catalyzed light-dependent transformation of protoheme to biliverdin IX alpha and biliverdin IX alpha to phycobilins, with or without the addition of NADPH and ferredoxin-NADP+ reductase. In the dark, neither reaction occurred unless NADPH and ferredoxin-NADP+ reductase were supplied. These results indicate that the only role of NADPH in both reactions of phycobilin biosynthesis, in vitro, is to reduce ferredoxin via ferredoxin-NADP+ reductase and that reduced ferredoxin can directly supply the electrons needed to drive both steps in the transformation of protoheme to phycocyanobilin.
Topics: Cell Fractionation; Ferredoxins; Heme; Heme Oxygenase (Decyclizing); Kinetics; Molecular Structure; NADP; Oxidation-Reduction; Phycobilins; Phycocyanin; Pyrroles; Rhodophyta; Tetrapyrroles
PubMed: 1644795
DOI: No ID Found -
Microbial Cell Factories Jul 2021The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging....
BACKGROUND
The development of multiple gene expression systems, especially those based on the physical signals, such as multiple color light irradiations, is challenging. Complementary chromatic acclimation (CCA), a photoreversible process that facilitates the control of cellular expression using light of different wavelengths in cyanobacteria, is one example. In this study, an artificial CCA systems, inspired by type III CCA light-regulated gene expression, was designed by employing a single photosensor system, the CcaS/CcaR green light gene expression system derived from Synechocystis sp. PCC6803, combined with G-box (the regulator recognized by activated CcaR), the cognate cpcG2 promoter, and the constitutively transcribed promoter, the P promoter.
RESULTS
One G-box was inserted upstream of the cpcG2 promoter and a reporter gene, the rfp gene (green light-induced gene expression), and the other G-box was inserted between the P promoter and a reporter gene, the bfp gene (red light-induced gene expression). The Escherichia coli transformants with plasmid-encoded genes were evaluated at the transcriptional and translational levels under red or green light illumination. Under green light illumination, the transcription and translation of the rfp gene were observed, whereas the expression of the bfp gene was repressed. Under red light illumination, the transcription and translation of the bfp gene were observed, whereas the expression of the rfp gene was repressed. During the red and green light exposure cycles at every 6 h, BFP expression increased under red light exposure while RFP expression was repressed, and RFP expression increased under green light exposure while BFP expression was repressed.
CONCLUSION
An artificial CCA system was developed to realize a multiple gene expression system, which was regulated by two colors, red and green lights, using a single photosensor system, the CcaS/CcaR system derived from Synechocystis sp. PCC6803, in E. coli. The artificial CCA system functioned repeatedly during red and green light exposure cycles. These results demonstrate the potential application of this CCA gene expression system for the production of multiple metabolites in a variety of microorganisms, such as cyanobacteria.
Topics: Escherichia coli; Gene Expression; Gene Expression Regulation, Bacterial; Genes, Reporter; Light; Luminescent Proteins; Phycobilins; Phycocyanin; Promoter Regions, Genetic; Synechocystis; Transcription, Genetic; Transformation, Bacterial; Red Fluorescent Protein
PubMed: 34225717
DOI: 10.1186/s12934-021-01621-3 -
Frontiers in Microbiology 2022Increased anthropogenic nutrient loading has led to eutrophication of aquatic ecosystems, which is the major cause of harmful cyanobacteria blooms. Element stoichiometry...
Increased anthropogenic nutrient loading has led to eutrophication of aquatic ecosystems, which is the major cause of harmful cyanobacteria blooms. Element stoichiometry of cyanobacteria bloom is subject to nutrient availabilities and may significantly contribute to primary production and biogeochemical cycling. Phycobilisome is the antenna of the photosynthetic pigment apparatus in cyanobacteria, which contains phycobilin pigments (PBPs) and linker proteins. This nitrogen (N)-rich protein complex has the potential to support growth as a N-storage site and may play a major role in the variability of cyanobacteria N stoichiometry. However, the regulation of PBPs during bloom formation remains unclear. We investigated the temporal variation of N allocation into PBPs and element stoichiometry for two ubiquitous cyanobacteria species, and , in a batch culture experiment with different initial N availabilities. Our results indicated that the N allocation into PBPs is species-dependent and tightly regulated by the availability of nutrients fueling population expansion. During the batch culture experiment, different nutrient uptake rates led to distinct stoichiometric imbalances of N and phosphorus (P), which substantially altered cyanobacteria C: N and C: P stoichiometry. invested cellular N into PBPs and exhibited greater flexibility in C: N and C: P stoichiometry than . The dynamics of such N-rich macromolecules may help explain the N stoichiometry variation during a bloom and the interspecific difference between and . Our study provides a quantitative understanding of the elemental stoichiometry and the regulation of PBPs for non-diazotrophic and diazotrophic cyanobacteria blooms.
PubMed: 35722313
DOI: 10.3389/fmicb.2022.850997 -
Scientific Reports Dec 2017Techniques such as Stochastic Optical Reconstruction Microscopy (STORM) and Structured Illumination Microscopy (SIM) have increased the achievable resolution of optical...
Techniques such as Stochastic Optical Reconstruction Microscopy (STORM) and Structured Illumination Microscopy (SIM) have increased the achievable resolution of optical imaging, but few fluorescent proteins are suitable for super-resolution microscopy, particularly in the far-red and near-infrared emission range. Here we demonstrate the applicability of CpcA, a subunit of the photosynthetic antenna complex in cyanobacteria, for STORM and SIM imaging. The periodicity and width of fabricated nanoarrays of CpcA, with a covalently attached phycoerythrobilin (PEB) or phycocyanobilin (PCB) chromophore, matched the lines in reconstructed STORM images. SIM and STORM reconstructions of Escherichia coli cells harbouring CpcA-labelled cytochrome bd ubiquinol oxidase in the cytoplasmic membrane show that CpcA-PEB and CpcA-PCB are suitable for super-resolution imaging in vivo. The stability, ease of production, small size and brightness of CpcA-PEB and CpcA-PCB demonstrate the potential of this largely unexplored protein family as novel probes for super-resolution microscopy.
Topics: Bacterial Proteins; Light-Harvesting Protein Complexes; Photosynthesis; Phycobilins; Phycocyanin; Phycoerythrin; Stochastic Processes; Synechocystis
PubMed: 29196704
DOI: 10.1038/s41598-017-16834-z -
Proceedings of the National Academy of... Feb 2020The three-dimensional (3D) crystal structures of the GAF3 domain of cyanobacteriochrome Slr1393 ( PCC6803) carrying a phycocyanobilin chromophore could be solved in both...
The three-dimensional (3D) crystal structures of the GAF3 domain of cyanobacteriochrome Slr1393 ( PCC6803) carrying a phycocyanobilin chromophore could be solved in both 15- dark-adapted state, Pr, λ = 649 nm, and 15- photoproduct, Pg, λ = 536 nm (resolution, 1.6 and 1.86 Å, respectively). The structural data allowed identifying the large spectral shift of the Pr-to-Pg conversion as resulting from an out-of-plane rotation of the chromophore's peripheral rings and an outward movement of a short helix formed from a formerly unstructured loop. In addition, a third structure (2.1-Å resolution) starting from the photoproduct crystals allowed identification of elements that regulate the absorption maxima. In this peculiar form, generated during X-ray exposition, protein and chromophore conformation still resemble the photoproduct state, except for the D-ring already in 15- configuration and tilted out of plane akin the dark state. Due to its formation from the photoproduct, it might be considered an early conformational change initiating the parental state-recovering photocycle. The high quality and the distinct features of the three forms allowed for applying quantum-chemical calculations in the framework of multiscale modeling to rationalize the absorption maxima changes. A systematic analysis of the PCB chromophore in the presence and absence of the protein environment showed that the direct electrostatic effect is negligible on the spectral tuning. However, the protein forces the outer pyrrole rings of the chromophore to deviate from coplanarity, which is identified as the dominating factor for the color regulation.
Topics: Bacterial Proteins; Binding Sites; Crystallography, X-Ray; Light; Models, Molecular; Photochemical Processes; Photoreceptors, Microbial; Phycobilins; Phycocyanin; Protein Conformation; Protein Domains; Structure-Activity Relationship; Synechocystis
PubMed: 31964827
DOI: 10.1073/pnas.1910208117 -
Frontiers in Microbiology 2023Cyanophages affect the abundance, diversity, metabolism, and evolution of picocyanobacteria in marine ecosystems. Here we report an estuarine phage, S-CREM2, which...
Cyanophages affect the abundance, diversity, metabolism, and evolution of picocyanobacteria in marine ecosystems. Here we report an estuarine phage, S-CREM2, which represents a novel viral genus and leads to the establishment of a new T4-like cyanophage clade named cluster C. S-CREM2 possesses the longest tail (~418 nm) among isolated cyanomyoviruses and encodes six tail-related proteins that are exclusively homologous to those predicted in the cluster C cyanophages. Furthermore, S-CREM2 may carry three regulatory proteins in the virion, which may play a crucial role in optimizing the host intracellular environment for viral replication at the initial stage of infection. The cluster C cyanophages lack auxiliary metabolic genes (AMGs) that are commonly found in cyanophages of the T4-like clusters A and B and encode unique AMGs like an S-type phycobilin lyase gene. A variation in the composition of tRNA and regulatory RNA genes was observed between the marine and freshwater phage strains in cluster C, reflecting their different modes of coping with hosts and habitats. The cluster C cyanophages are widespread in estuarine and coastal regions and exhibit equivalent or even higher relative abundance compared to those of clusters A and B cyanophages in certain estuarine regions. The isolation of cyanophage S-CREM2 provides new insights into the phage-host interactions mediated by both newly discovered AMGs and virion-associated proteins and emphasizes the ecological significance of cluster C cyanophages in estuarine environments.
PubMed: 38029084
DOI: 10.3389/fmicb.2023.1293846 -
Biomolecules Dec 2020The Balaruc-les-Bains' thermal mud was found to be colonized predominantly by microorganisms, with cyanobacteria constituting the primary organism in the microbial...
The Balaruc-les-Bains' thermal mud was found to be colonized predominantly by microorganisms, with cyanobacteria constituting the primary organism in the microbial biofilm observed on the mud surface. The success of cyanobacteria in colonizing this specific ecological niche can be explained in part by their taxa-specific adaptation capacities, and also the diversity of bioactive natural products that they synthesize. This array of components has physiological and ecological properties that may be exploited for various applications. Nine cyanobacterial strains were isolated from Balaruc thermal mud and maintained in the Paris Museum Collection (PMC). Full genome sequencing was performed coupled with targeted and untargeted metabolomic analyses (HPLC-DAD and LC-MS/MS). Bioassays were performed to determine antioxidant, anti-inflammatory, and wound-healing properties. Biosynthetic pathways for phycobiliproteins, scytonemin, and carotenoid pigments and 124 metabolite biosynthetic gene clusters (BGCs) were characterized. Several compounds with known antioxidant or anti-inflammatory properties, such as carotenoids, phycobilins, mycosporine-like amino acids, and aeruginosins, and other bioactive metabolites like microginins, microviridins, and anabaenolysins were identified. Secretion of the proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-8 appeared to be inhibited by crude extracts of PMC 877.14, sp. PMC 881.14, and PMC 885.14. The extract of the sp. PMC 882.14 strain was able to slightly enhance migration of HaCat cells that may be helpful in wound healing. Several antioxidant compounds were detected, but no significant effects on nitric oxide secretion were observed. There was no cytotoxicity on the three cell types tested, indicating that cyanobacterial extracts may have anti-inflammatory therapeutic potential without harming body cells. These data open up promising uses for these extracts and their respective molecules in drugs or thermal therapies.
Topics: Animals; Anti-Inflammatory Agents; Antioxidants; Biological Products; Cell Line; Cell Movement; Cyanobacteria; France; Genome, Bacterial; Humans; Mice; Mud Therapy; RAW 264.7 Cells; Wound Healing
PubMed: 33383796
DOI: 10.3390/biom11010028 -
Nature Communications Jul 2019The Gram-positive bacterium Bacillus subtilis exhibits complex spatial and temporal gene expression signals. Although optogenetic tools are ideal for studying such...
The Gram-positive bacterium Bacillus subtilis exhibits complex spatial and temporal gene expression signals. Although optogenetic tools are ideal for studying such processes, none has been engineered for this organism. Here, we port a cyanobacterial light sensor pathway comprising the green/red photoreversible two-component system CcaSR, two metabolic enzymes for production of the chromophore phycocyanobilin (PCB), and an output promoter to control transcription of a gene of interest into B. subtilis. Following an initial non-functional design, we optimize expression of pathway genes, enhance PCB production via a translational fusion of the biosynthetic enzymes, engineer a strong chimeric output promoter, and increase dynamic range with a miniaturized photosensor kinase. Our final design exhibits over 70-fold activation and rapid response dynamics, making it well-suited to studying a wide range of gene regulatory processes. In addition, the synthetic biology methods we develop to port this pathway should make B. subtilis easier to engineer in the future.
Topics: Bacillus subtilis; Bacterial Proteins; Gene Expression Regulation, Bacterial; Light; Metabolic Engineering; Optogenetics; Photoreceptors, Microbial; Phycobilins; Phycocyanin; Phytochrome; Promoter Regions, Genetic; Protein Kinases
PubMed: 31308373
DOI: 10.1038/s41467-019-10906-6 -
Polymers Mar 2023The food industry is a high consumer of polymer packing materials, sealing materials, and engineering components used in production equipment. Biobased polymer...
The food industry is a high consumer of polymer packing materials, sealing materials, and engineering components used in production equipment. Biobased polymer composites used in the food industry are obtained by incorporating different biogenic materials into the structure of a base polymer matrix. Renewable resources such as microalgae, bacteria, and plants may be used as biogenic materials for this purpose. Photoautotrophic microalgae are valuable microorganisms that are able to harvest sunlight energy and capture CO into biomass. They are characterized by their metabolic adaptability to environmental conditions, higher photosynthetic efficiency than terrestrial plants, and natural macromolecules and pigments. The flexibility of microalgae to grow in either low-nutrient or nutrient-rich environments (including wastewater) has led to the attention for their use in various biotechnological applications. Carbohydrates, proteins, and lipids are the main three classes of macromolecular compounds contained in microalgal biomass. The content in each of these components depends on their growth conditions. In general, proteins represent 40-70% of microalgae dry biomass, followed by carbohydrates (10-30%) and lipids (5-20%). A distinctive feature of microalgae cells is the presence of light-harvesting compounds such as photosynthetic pigments carotenoids, chlorophylls, and phycobilins, which are also receiving growing interest for applications in various industrial fields. The study comparatively reports on polymer composites obtained with biomass made of two species of green microalgae: and filamentous, gram-negative cyanobacterium . Experiments were conducted to reach an incorporation ratio of the biogenic material into the matrix in the 5-30% range, and the resulting materials were characterized by their mechanical and physicochemical properties.
PubMed: 36987138
DOI: 10.3390/polym15061357