Immunochemistry on Cryptomonad Biliproteins

Abstract

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 ...

Occurrence and Localization of Phycoerythrin in Symbiotic Nostoc of Cycas revoluta and in the Free-Living Isolated Nostoc 7422

“…The Mr observed correspond to those described for other cyanobacteria (7). Furthermore, using Ouchterlony diffusion technique, no recognition was observed between the C-phycoerythrin antiserum used in the present study and purified cryptomonad phycoerythrin and phycocyanin (8).…”

“…Free-living Nostoc 7422 (PCC 7422, ATCC 29132), originally isolated from the cycad Cycas sp., was obtained from the Pasteur Culture Collection (Paris, France). Cells were grown and harvested as described earlier (16 (6) except that the nitrocellulose-membranes were incubated with primary antiserum against C-phycoerythrin purified from the cyanobacterium Phormidium persicinum (rabbit anti-C-phyroerythrin antiserum, 1:500 dilution) (8).…”

Compartmentalisation of nitrogenase in a non-heterocystous cyanobacterium: Trichodesmium contortum

“…Anti-PE antibodies were a kind gift from Dr. D. Guard-Friar (State of NY Dept. of Health, Albany, NY, USA [13]). The anti-PE antibodies are monospecific against PE in a wide range of cyanobacteria including Trichodesmium [14].…”

The Nostoc‐Nephroma symbiosis: localization, distribution pattern and levels of key proteins involved in nitrogen and carbon metabolism of the cyanobiont

“…of Chicago, USA; Orr and Haselkorn 1982). The PE antiserum was raised against the purified PE from Phormidium persicinum (a gift from D. Guard-Friar, USA; Guard-Friar et al 1986). The Rubisco (EC 4.1,1,39) antiserum was…”