SUBUNIT SEPARATION (α, αprime;, β) OF CRYPTOMONAD BILIPROTEINS *

Guard-Friar, Deborah; MacColl, Robert

doi:10.1111/j.1751-1097.1986.tb05594.x

Cited by 30 publications

(9 citation statements)

References 11 publications

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“…Its chromophore content is unique and differs from that of C-phycocyanin in that its ,B subunit has a cryptoviolin chromophore in addition to the usual two phycocyanobilins. Its a subunit, however, has the same chromophore content as C-phycocyanin but differs from that found for cryptomonad phycocyanin 645 (15,18). A common feature in the chromophore contents of cryptomonad biliproteins is that cryptoviolin is always present ( 14,(17)(18)(19).…”

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confidence: 85%

Immunochemistry on Cryptomonad Biliproteins

Guard-Friar¹,

Eisenberg²,

Edwards³

et al. 1986

Plant Physiol.

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ABSTRACIA survey is made of the immunochemical behavior of four of the six known types of cryptomonad biliproteins: phycocyanins 612 and 645 and phycoerythrins 545 and 566. They were compared both among themselves and to selected biliproteins isolated from blue-green and red algae. All the cryptomonad biliproteins were shown to be closely related to each other by Ouchterlony double diffusion technics. An antigenic relationship among all the cryptomonad biliproteins and B-phycoerythrin (red alp) and C-phycoerythrin (blue-green alga) was established. Only a very marginal cross-reactivity was found between C-phycocyanin (blue-green algae) and the cryptomonad biliproteins. These results suggest a common ancestor for the photosynthetic units of all three biliprotein-containing phyla.Biliproteins are light harvesting and excitation energy transfer chromoproteins that function as accessory pigments for PSII in the photosynthesis of blue-green (cyanobacterial), red, and cryptomonad algae. Cryptomonad biliproteins are unusual in that they apparently do not form phycobilisomes and in the cryptomonads no analog of allophycocyanin has yet been detected. There are six biliproteins in the cryptomonads, phycocyanins 612, 630, 645, and phycoerythrins 545, 555, 566, with only one type usually found in each alga.Immunochemical studies on biliproteins have greatly emphasized blue-green and red algal examples. By 1967 four publications had established in a very extensive and decisive manner three basic rules governing the immunochemical behavior of these two types of algal biliproteins (1-3, 29). These three generalizations are: all phycocyanins from both blue-green (procaryotes) or red (eucaryotes) algae are immunochemically very similar; all phycoerythrins of all spectral types (C-, R-, B-) are immunochemically closely related whether they are from bluegreen or red algae; no phycocyanin is related immunochemically to any phycoerythrin. This last rule holds even when the phycocyanin and phycoerythrin are isolated from the same alga. These first two results were most important because of the great differences in structure between procaryotic blue-green algae and eucaryotic red algae. The immunochemical results then established the principle that, although major cellular changes have occurred in the evolution from procaryotes to eucaryotes, the individual proteins could remain virtually unaltered. Subsequent research has shown that the two subunits of phycoerythrin are immunochemically related (27) Research on the immunochemistry of cryptomonad biliproteins, has been much less extensive and then usually only a fragment of a larger study. It is therefore not too surprising that unlike the comparison of blue-green and red algal biliproteins, cryptomonad results have been so far perhaps inconclusive and controversial (2,4,12,13,16,26,29). We, therefore, undertook an immunochemical investigation using Ouchterlony doublediffusion and four different cryptomonad biliproteins. Two different phycoerythrins and two different phycocyanins ...

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confidence: 85%

Immunochemistry on Cryptomonad Biliproteins

Guard-Friar¹,

Eisenberg²,

Edwards³

et al. 1986

Plant Physiol.

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“…Three different Cr-PEs (Cr-PE 545, Cr-PE 555, and Cr-PE 566) and four distinct Cr-PCs (Cr-PC 569, Cr-PC 612, Cr-PC 630, and Cr-PC 645) have been described (Hill and Rowan 1989;Wedemayer et al 1991). These biliproteins are isolated as -,~50,000 kDa c~c~'32 complexes (e.g., MOrschel and Wehrmeyer 1975;Sidler et al 1985;Guard-Friar and MacColl 1986) which carry one covalently bound bilin on the a and three on the 3 subunit. The a subunits are encoded by a small nuclear multigene family (Jenkins et al 1990), while the/3 subunit is encoded on the chloroplast genome (Douglas 1992).…”

Section: Introductionmentioning

confidence: 99%

Cryptomonad biliproteins: Bilin types and locations

1996

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Two crytophycean phycocyanins (Cr-PCs), Hemiselmis strain HP9001 Cr-PC 612 and Falcomonas daucoides Cr-PC 69 were purified and characterized with respect to bilin numbers, types and locations. Each biliprotein carried one bilin on the α subunit and three on the β subunit. Cr-PC 612 carried phycocyanobilin at α-Cys-18, β-Cys-82, and β-Cys-158, and a doubly-linked 15,16-dihydrobiliverdin at β-DiCys-50,61. Cr-PC 569 carried phycocyanobilin at α-Cys-18 and β-Cys-82, a singly-linked Bilin 584 at β-Cys-158, and a doubly-linked Bilin 584 at β-DiCys-50,61. This work, in conjunction with earlier studies on Cr-PE 545, Cr-PE 555, Cr-PE 566, and Cr-PC 645, shows that there is no conserved location for the bilin with longest wavelength visible absorption band among these proteins, and, consequently, that there is no conserved energy transfer pathway common to all native cryptophycean biliproteins. Only phycocyanobilin or phycoerythrobilin is found at β-Cys-82; there is greater bilin variability at the other three attachment sites.

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“…The biliprotein phycocyanin 612 is a photosynthetic antenna pigment of the cryptomonad Hemiselmis virescem. Its polypeptide structure and chromophore content have been described (MacColl and Guard-Friar, 1983;Guard-Friar and MacColl, 1986).…”

Section: Introductionmentioning

confidence: 99%

Excitation Energy Transfer Between Sensitizing Chromophores of Phycocyanin 612

Csatorday

MacColl

Guard-Friar

et al. 1987

Photochem & Photobiology

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Abstract. The visible absorption and circular dichroism spectra of phycocyanin 612 were each resolved into four components. The deconvolution required the blue side of each spectrum to be fitted by a half‐Lorentzian band and the remainder of the spectrum by Gaussian components. The energy levels of the components in the deconvolution allowed analysis of the discrete steps in the transfer of excitation energy within the biliprotein. By comparison of the deconvolution of the absorption spectrum to the published results from ultrafast fluorescence kinetics of phycocyanin 612, the times for s‐to‐s and s‐to‐f excitation energy transfer are established. This is the first evidence of excitation energy transfer between two types of sensitizing (s) chromophores in a biliprotein. The analysis of the ultrafast kinetics and the deconvolution of the absorption spectrum allowed the assignments of 7–10 ps to the transfer of excitons from an s to a fluorescing (f) chromophore and a time faster than 7 ps to the transfer of excitons between two spectrally distinct s chromophores. The steady‐state fluorescence polarization spectrum of this biliprotein supports the hypothesis that excitation energy transfer occurs between s chromophores.

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SUBUNIT SEPARATION (α, αprime;, β) OF CRYPTOMONAD BILIPROTEINS *

Cited by 30 publications

References 11 publications

Immunochemistry on Cryptomonad Biliproteins

Immunochemistry on Cryptomonad Biliproteins

Cryptomonad biliproteins: Bilin types and locations

Excitation Energy Transfer Between Sensitizing Chromophores of Phycocyanin 612

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