Properties and <i>N</i>-terminal sequence of allophycocyanin from the unicellular rhodophyte <i>Cyanidium caldarium</i>

Brown, Anne S.; Troxler, Robert F.

doi:10.1042/bj1630571

Cited by 37 publications

(12 citation statements)

References 40 publications

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“…This band is shifted to 625 nm and diminishes in intensity in pH 8.0 phosphate buffer, I 0.1. This spectrum is generally similar to those obtained with protein from either mesophilic or thermophilic algae (5,6).…”

Section: C-supporting

confidence: 63%

“…At pH 7.0, the predominant 6S species was virtually completely converted to I I S hexamer in the presence of 2 M salt. At pH 6.0 no perturbation of 6S-1 1S equilibrium was noted, probably due to the initial presence of large amounts of hexamer (82% before the addition of salt). C-Phycocyanin solutions were dialyzed at pH 7.0 in the presence of a saturated benzene solution or 0.01 M phenol solution.…”

Section: C-mentioning

confidence: 99%

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Psychrophile C-Phycocyanin

Adams¹,

Kao²,

Berns³

1979

Plant Physiol.

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C-Phycocyanin was purified from an alga isolated in the Antarctic in 1968 and grown since that time in our laboratory at 4 C. Certain of its spectroscopic and immunochemical properties were studied, along with detailed examinations of its chemical composition and quaternary structure. The hexamer-trmer equilibrium in the protein solution was studied as a function of pH, ionic strength, temperature, and susceptibility to certain small molecules. A major emphasis of the work was placed on a comparison of its protein-protein interactions with those of C-phycocyanins from both mesophilic and thermophilk algae.The chromoprotein C-phycocyanin, an accessory photosynthetic pigment found in blue-green and red algae, has been examined in this laboratory from a variety of algal species that grow at extremes of temperature, salinity, and acidity (2, 13-16, 18, 19). In particular, C-phycocyanin isolated from thermotolerant organisms has been studied in an effort to understand what modifications in phycocyanin structure could occur at the molecular level to adjust to this environmental extreme. Sedimentation velocity experiments have shown the interesting result that the aggregation of this protein is saliently changed when mesophilic and thermophilic C-phycocyanins are compared. To have a more complete view of this concept, it is desirable to obtain data on algae that thrive in very cold environments. Will such C-phycocyanin behave as those from the higher temperature organisms and display peculiar aggregation, or will the needs of life in the cold require no changes in these parameters?To determine whether survival at low temperature has an influence on protein properties, we report in the present work observations on aggregation behavior, amino acid composition, subunit structure, isoelectric point, absorption, fluorescence, and circular dichroism spectra, and immunochemical properties of Cphycocyanin isolated from the psychrophilic blue-green alga, Microcoleus vaginatus. These findings will be compared with those for C-phycocyanin from mesophilic and thermophilic algae. The general problem of biological adaptation to cold has been reviewed (7,12) (9) for carbohydrate. Allophycocyanin and phycoerythrin were also purified by ammonium sulfate fractionation from this alga. In general, the phycoerythrin precipitated with lower and allophycocyanin with higher ammonium sulfate concentrations than C-phycocyanin. Isoelectric focusing was performed on the 110 ml LKB Ampholine column (8101) with a sucrose gradient as a stabilizing system.The amino acid analysis employed the method of Spackman et al. (23) with 6 N HCI hydrolysis at 110 C. An analysis was also performed with 4 N methanesulfonic acid hydrolysis at 110 C for 22 h to ascertain the presence of tryptophan (22).Fluorescence spectra were obtained with a Baird-Atomic fluorescence spectrophotometer SF-1 at room temperature (23 C). An RCA model 4832 photomultiplier was used since its spectral response did not change significantly over the region 300 to 800 nm. The A i...

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Section: C-supporting

confidence: 63%

Section: C-mentioning

confidence: 99%

Psychrophile C-Phycocyanin

Adams¹,

Kao²,

Berns³

1979

Plant Physiol.

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“…[17][18][19][20] Foguel and Weber 5 were also able to obtain subunits by the application of low temperature at high pressure, and they showed that the visible spectra of the subunits had a similar shape and maximum but much lower intensity than that of monomers. Schneider and coworkers 21 also studied spectral changes in biliproteins that were induced by high pressures.…”

Section: Subunits and Their Complex Behaviors In Reassociation Experimentioning

confidence: 95%

Allophycocyanin: Trimers, monomers, subunits, and homodimers

2003

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Allophycocyanin is a photosynthetic light-harvesting pigment-protein complex located in the phycobilisomes of cyanobacteria and red algae. Using dynamic light scattering and circular dichroism, solutions of purified allophycocyanin were shown to consist of homogeneous trimers (alpha3beta3) with a nonspherical shape over a very wide range of protein concentrations at pH 6.0 and 20 degrees C. Deconvolutions of the visible circular dichroism spectrum of the trimer were carried out for the first determination of the individual spectra of all six-component chromophores. The chromophores were shown to be in different microenvironments that helped determine the spectrum of the trimer. Monomers (alpha beta) that were formed in either the presence of 0.50M NaSCN or at 45 degrees C were shown to be completely reversible to trimers. However, subunits (alpha and beta) that were formed in either the presence of 8M urea or at 60 degrees C, using spectroscopy and gel-filtration column chromatography, were observed to only partially reconstitute trimers. Homodimers (alpha2 and/or beta2) formed during the regeneration of trimers. The homodimer, which was detected for the first time when both subunits were present, was shown to be in equilibrium with its subunits. Unlike the trimer situation, subunits were found to fully reconstitute monomers in the presence of 0.50M NaSCN. These results suggest a route to trimer assembly from subunits with monomers serving as intermediaries and the homodimers forming in a nonproductive step that did not interfere with the overall assembly scheme.

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“…Native APC from Synechocystis sp. PCC 6803 was isolated on a brushite (CaHPO 4 Á2H 2 O) column, and further purified with a Superdex 200 size-exclusion column (Brown and Troxler 1977), and digested as above.…”

Section: Tryptic Digestion Of Apcmentioning

confidence: 99%

Biosynthesis of fluorescent cyanobacterial allophycocyanin trimer in Escherichia coli

Liu

Chen

et al. 2010

Photosynth Res

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Allophycocyanin (APC), a cyanobacterial photosynthetic phycobiliprotein, functions in energy transfer as a light-harvesting protein. One of the prominent spectroscopic characteristics of APC is a strong red-shift in the absorption and emission maxima when monomers are assembled into a trimer. Previously, holo-APC a and b subunits (holo-ApcA and ApcB) were successfully synthesized in Escherichia coli. In this study, both holo-subunits from Synechocystis sp. PCC 6803 were co-expressed in E. coli, and found to self-assemble into trimers. The recombinant APC trimer was purified by metal affinity and size-exclusion chromatography, and had a native structure identical to native APC, as determined by characteristic spectroscopic measurements, fluorescence quantum yield, tryptic digestion analysis, and molecular weight measurements. Combined with results from a study in which only the monomer was formed, our results indicate that bilin synthesis and the subsequent attachment to apo-subunits are important for the successful assembly of APC trimers. This is the first study to report on the assembly of recombinant ApcA and ApcB into a trimer with native structure. Our study provides a promising method for producing better fluorescent tags, as well as a method to facilitate the genetic analysis of APC trimer assembly and biological function.

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Properties and N-terminal sequence of allophycocyanin from the unicellular rhodophyte Cyanidium caldarium

Cited by 37 publications

References 40 publications

Psychrophile C-Phycocyanin

Psychrophile C-Phycocyanin

Allophycocyanin: Trimers, monomers, subunits, and homodimers

Biosynthesis of fluorescent cyanobacterial allophycocyanin trimer in Escherichia coli

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