Photophysical Properties of Phycobiliproteins From Phycobilisomes: Fluorescence Lifetimes, Quantum Yields, and Polarization Spectra

Grabowski, J.; Gantt, Elisabeth

doi:10.1111/j.1751-1097.1978.tb06927.x

Cited by 134 publications

(56 citation statements)

References 33 publications

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“…2D). The decline in absorbance was primarily attributed to a decrease in chlorophyll concentration in single cells, because even the longest wavelength-absorbing subunit of PBS, APC, showed only 5% to 7% of absorbance compared with the peak at around 650 nm (Grabowski and Gantt, 1978;Murakami et al, 1981;Rolinski et al, 1999;MacColl et al, 2003). Based on these absorbance values and an estimate of the optical path length (Supplemental Text S4), the total amounts of chlorophyll in the terminal and intercalary heterocysts were estimated to be 50% and 71%, respectively, of that in a vegetative cell (Supplemental Table S2).…”

Section: Number and Oligomeric Status Of Psi And Psii In Single Cellsmentioning

confidence: 99%

Transformation of Thylakoid Membranes during Differentiation from Vegetative Cell into Heterocyst Visualized by Microscopic Spectral Imaging

2012

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Some filamentous cyanobacteria carry out oxygenic photosynthesis in vegetative cells and nitrogen fixation in specialized cells known as heterocysts. Thylakoid membranes in vegetative cells contain photosystem I (PSI) and PSII, while those in heterocysts contain predominantly PSI. Therefore, the thylakoid membranes change drastically when differentiating from a vegetative cell into a heterocyst. The dynamics of these changes have not been sufficiently characterized in situ. Here, we used time-lapse fluorescence microspectroscopy to analyze cells of Anabaena variabilis under nitrogen deprivation at approximately 295 K. PSII degraded simultaneously with allophycocyanin, which forms the core of the light-harvesting phycobilisome. The other phycobilisome subunits that absorbed shorter wavelengths persisted for a few tens of hours in the heterocysts. The wholethylakoid average concentration of PSI was similar in heterocysts and nearby vegetative cells. PSI was best quantified by selective excitation at a physiological temperature (approximately 295 K) under 785-nm continuous-wave laser irradiation, and detection of higher energy shifted fluorescence around 730 nm. Polar distribution of thylakoid membranes in the heterocyst was confirmed by PSI-rich fluorescence imaging. The findings and methodology used in this work increased our understanding of how photosynthetic molecular machinery is transformed to adapt to different nutrient environments and provided details of the energetic requirements for diazotrophic growth.

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Section: Number and Oligomeric Status Of Psi And Psii In Single Cellsmentioning

confidence: 99%

Transformation of Thylakoid Membranes during Differentiation from Vegetative Cell into Heterocyst Visualized by Microscopic Spectral Imaging

2012

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“…where C is a collection of constants that considers a refraction index n = 1.567 [19,20,37,38], S include the spectroscopic properties of the interacting chromophores, I is the overlap integral between the emission and absorption spectra of the donor and acceptor chromophores respectively as described in [20]. Considering the homology among phycocyanins [39] and the structural similarity of the residues in contact with the chromophores (Fig.…”

Section: Energy Transfer Calculationsmentioning

confidence: 99%

The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC–PC complex

Contreras‐Martel

Matamala

Bruna

et al. 2007

Biophysical Chemistry

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Phycocyanin is a phycobiliprotein involved in light harvesting and conduction of light to the reaction centers in cyanobacteria and red algae. The structure of C-phycocyanin from Gracilaria chilensis was solved by X-ray crystallography at 2.0 Å resolution in space group P2 1 . An interaction model between two PC heterohexamers was built, followed by molecular dynamic refinement. The best model showed an inter-hexamer rotation of 23°. The coordinates of a PC heterohexamer (αβ) 6 and of the PC-PC complex were used to perform energy transfer calculations between chromophores pairs using the fluorescence resonance energy transfer approach (FRET). Two main intra PC (

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“…Spectra were determined at room temperature as described (17). For fluorescence spectra, samples were diluted in KPO4 (pH 7.0) to a protein concentration ofca.…”

Section: Methodsmentioning

confidence: 99%

Formation of hybrid phycobilisomes by association of phycobiliproteins from Nostoc and Fremyella

Canaani

Gantt

1982

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

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Formation of phycobilisomes has been accomplished in vitro from isolated phycobiliprotein fractions obtained from the same blue-green alga (intrageneric) and from different blue-green algae (intergeneric). Phycobilisomes, which are supramolecular complexes of phycobiliproteins, serve as major lightharvesting antennae for photosynthesis in blue-green and red algae. Intrageneric association into energetically functional phycobilisomes, previously reported to occur with Nostoc sp. allophycocyanin and phycoerythrin-phycocyanin complexes [Canaani, O., Lipschultz, C. A. & Gantt, E. (1980) FEBS Lett 115,[225][226][227][228][229], has been obtained with FremyeUa diplosiphon. By their spectral properties (absorption, fluorescence excitation, and emission) and electron microscopic images, the native and in vitro-associated phycobilisomes were virtually indistinguishable. Intergeneric phycobilisomes have been produced from allophycocyanin ofNostoc sp. strain Mac. and phycoerythrin-phycocyanin of F. diplosiphon, as well as from the reverse mixtures. The yield of intergeneric phycobilisomes, favored by higher phycobiliprotein content in 0.75 M phosphate, pH 7.0/2.0 M sucrose, was 40-60%. Energy transfer to the terminal long-wavelength-emitting allophycocyanin in the phycobilisomes was evident from the 670-675 nm fluorescence emission peaks. Furthermore, excitation spectra showed the contribution ofthe respective phycoerythrins (Fremyella, Am. 570; Nostoc, Am 573 and 553 nm), as well as that of phycocyanin and short-wavelength-absorbing allophycocyanin. Phycobilisomes of Nostoc and Fremyella, analyzed by NaDodSO4/polyacrylamide gel electrophoresis, possessed a number ofpolypeptides having similar molecular weights: the usual a-and ,B-phycobilin-containing polypeptides of Mr 15,000-22,000, a faint band at Mr ca. 95,000, and a prominent band at Mr ca. 31,000. The Mr 31,000 polypeptide is assumed to provide the recognition site for attachment of the phycoerythrin-phycocyanin complexes with the allophycocyanin core. In vitro association was not obtained between allophycocyanin from Nostoc and phycoerythrin-phycocyanin complexes from Phormium persicinum or Porphyridium sordidum.

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Photophysical Properties of Phycobiliproteins From Phycobilisomes: Fluorescence Lifetimes, Quantum Yields, and Polarization Spectra

Cited by 134 publications

References 33 publications

Transformation of Thylakoid Membranes during Differentiation from Vegetative Cell into Heterocyst Visualized by Microscopic Spectral Imaging

Transformation of Thylakoid Membranes during Differentiation from Vegetative Cell into Heterocyst Visualized by Microscopic Spectral Imaging

The structure at 2 Å resolution of Phycocyanin from Gracilaria chilensis and the energy transfer network in a PC–PC complex

Formation of hybrid phycobilisomes by association of phycobiliproteins from Nostoc and Fremyella

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