Phycocyanin in physical chemical studies

Berns, Donald S.; MacColl, Robert

doi:10.1021/cr00094a005

Cited by 91 publications

(67 citation statements)

References 66 publications

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“…Phycocyanin is isomerised by high pH and urea concentrations (Berns and Maccoll, 1989), both common conditions in WSPs, and hence the dissolved pigment is not detected by spectrofluorometry within hours to days of cell lysis. This results in an apparent lag in cyanobacterial reduction following H 2 O 2 addition.…”

Section: Cyanobacterial Dynamicsmentioning

confidence: 99%

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Barrington

Ghadouani

Ivey

2013

Hydrol. Earth Syst. Sci.

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Abstract. Cyanobacteria and cyanotoxins are a risk to human and ecological health, and a hindrance to biological wastewater treatment. This study investigated the use of hydrogen peroxide (H 2 O 2 ) for the removal of cyanobacteria and cyanotoxins from within waste stabilization ponds (WSPs). The daily dynamics of cyanobacteria and microcystins (commonly occurring cyanotoxins) were examined following the addition of H 2 O 2 to wastewater within both the laboratory and at the full scale within a maturation WSP, the final pond in a wastewater treatment plant. Hydrogen peroxide treatment at concentrations ≥ 0.1 mg H 2 O 2 µg −1 total phytoplankton chlorophyll a led to the lysis of cyanobacteria, in turn releasing intracellular microcystins to the dissolved state. In the full-scale trial, dissolved microcystins were then degraded to negligible concentrations by H 2 O 2 and environmental processes within five days. A shift in the phytoplankton assemblage towards beneficial Chlorophyta species was also observed within days of H 2 O 2 addition. However, within weeks, the Chlorophyta population was significantly reduced by the re-establishment of toxic cyanobacterial species. This re-establishment was likely due to the inflow of cyanobacteria from ponds earlier in the treatment train, suggesting that whilst H 2 O 2 may be a suitable short-term management technique, it must be coupled with control over inflows if it is to improve WSP performance in the longer term.

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Section: Cyanobacterial Dynamicsmentioning

confidence: 99%

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Barrington

Ghadouani

Ivey

2013

Hydrol. Earth Syst. Sci.

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“…Conversely, phycobilisomes/phycobiliproteins are denatured and almost depigmented after exposure to organic solvents (Cohen-Bazire and Bryant, 1982;MacColl, 1983), and, therefore, they are commonly extracted in phosphate buffer solution at neutral (or slightly acidic) pH. In aqueous solvents, phycobiliproteins may dissociate, forming lower weight complexes, depending on the organism of origin as well as on the extraction conditions, such as the solvent, the ionic-strength, the pH and their own concentration (MacColl, 1983;Glazer, 1988;Berns and MacColl, 1989). The main components of phycobiliproteins are protein subunits α and β, which form the monomeric unit (αβ).…”

Section: Introductionmentioning

confidence: 99%

Chlorophyll a interference in phycocyanin and allophycocyanin spectrophotometric quantification

et al. 2017

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The accurate quantification of cyanobacteria phycobiliproteins is an important aspect in various research topics, such as cyanobacteria ecology and physiology studies, and especially to calibrate algorithms used in remote sensing of cyanobacterial blooms. Here we present a spectroscopic approach, exploiting spectrophotometric equations, aimed at improving the phycocyanin and allophycocyanin quantification when chlorophyll a is present in the phycobiliprotein aqueous extract.

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“…C-PC is a water-soluble three-pigment protein found in phycobilisomes (20,21), which are specialized antenna complexes (22) that expand spectral coverage, absorb additional energy, and provide photoprotection in cyanobacteria (23,24). Recently observed "blinking" in single intact phycobilisomes, of unknown origin and not predicted de novo based on crystal structure, has been proposed to play a key role in photoprotection and light adaptation (25).…”

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confidence: 99%

Direct single-molecule measurements of phycocyanobilin photophysics in monomeric C-phycocyanin

Squires

Moerner

2017

Proc. Natl. Acad. Sci. U.S.A.

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Phycobilisomes are highly organized pigment-protein antenna complexes found in the photosynthetic apparatus of cyanobacteria and rhodophyta that harvest solar energy and transport it to the reaction center. A detailed bottom-up model of pigment organization and energy transfer in phycobilisomes is essential to understanding photosynthesis in these organisms and informing rational design of artificial light-harvesting systems. In particular, heterogeneous photophysical behaviors of these proteins, which cannot be predicted de novo, may play an essential role in rapid light adaptation and photoprotection. Furthermore, the delicate architecture of these pigment-protein scaffolds sensitizes them to external perturbations, for example, surface attachment, which can be avoided by study in free solution or in vivo. Here, we present single-molecule characterization of C-phycocyanin (C-PC), a threepigment biliprotein that self-assembles to form the midantenna rods of cyanobacterial phycobilisomes. Using the Anti-Brownian Electrokinetic (ABEL) trap to counteract Brownian motion of single particles in real time, we directly monitor the changing photophysical states of individual C-PC monomers from Spirulina platensis in free solution by simultaneous readout of their brightness, fluorescence anisotropy, fluorescence lifetime, and emission spectra. These include single-chromophore emission states for each of the three covalently bound phycocyanobilins, providing direct measurements of the spectra and photophysics of these chemically identical molecules in their native protein environment. We further show that a simple Förster resonant energy transfer (FRET) network model accurately predicts the observed photophysical states of C-PC and suggests highly variable quenching behavior of one of the chromophores, which should inform future studies of higherorder complexes.photosynthetic protein | C-phycocyanin | ABEL trap | single-molecule spectroscopy | photodynamics P hotosynthetic antenna structures based on pigment-protein complexes have garnered broad interest as model systems for solar energy harvesting that can directly inform development of alternative energy technologies (1). These systems transfer absorbed energy quickly and efficiently to reaction centers, and must rapidly adapt to changing irradiance to maintain photosynthetic efficiency while protecting against oxidative damage. These macroscopic behaviors of photosynthetic antenna systems are dictated by the nanoscale heterogeneous properties of the individual proteins from which they are assembled; therefore, constructing bottom-up models will be essential to fully understanding these systems. A variety of standard single-molecule techniques have been previously used to optically characterize individual antenna complexes and their substituent components, for example at low concentration (2-4) or immobilized on a surface (5-9) or in a polymer matrix (10). However, studying photosynthetic antenna proteins at the single-molecule level remains challenging (11) due to the...

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Phycocyanin in physical chemical studies

Cited by 91 publications

References 66 publications

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Cyanobacterial and microcystins dynamics following the application of hydrogen peroxide to waste stabilisation ponds

Chlorophyll a interference in phycocyanin and allophycocyanin spectrophotometric quantification

Direct single-molecule measurements of phycocyanobilin photophysics in monomeric C-phycocyanin

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