Cyanobacteria phycobiliprotein

The algal extract of P. aerugineum is blue, with maximum absorbance at a wavelength of 620 nm and a red fluorescence with maximum emission at 642 nm. The main phycobiliprotein, C-phycocyanin, is the same type of phycocyanin found in most Cyanobacteria. The chromophores are composed of phycocyanobilins, conjugated to an apoprotein via thioether bonds. 

Despite these problems, flow cytometry has had some noted success in aquatic research, particularly in relation to studies on the phytoplankton. Because all phytoplankton possess chlorophyll, but only the cyanobacteria possess the phycobiliproteins, autofluorescence signatures from water samples, based on the chlorophyll (fluorescence >630 nm), phycoerythrin (fluorescence <590 nm), and forward scatter of particles, have been used to characterize the changes that occur in plankton at different depths or at different locations (Figs. 11.5 and 11.6). 

Phycobiliproteins are found also in cryptophytes but, differently from cyanobacteria and red algae, they are not organized into a phycobilisome, but instead they are located in the thylakoid lumen. Unique for cryptophytes, their phycobiliproteins do not exhibit a trimeric aggregation state characteristic for cyanobacteria, but instead they are present as ai(3a2(3 heterodimers, with each a subunit having a distinct amino acid sequence. [40]... 

Collier, J. L., and Grossman, A. R. (1994). A small polypeptide triggers complete degradation ofHght-harvesting phycobiliproteins in nutrient-deprived cyanobacteria. EMBOJ. 13, 1039—1047. 

Phycobiliproteins, such as phycocyanin and phycoerythrin, are members of a family of fluorescent accessory, nonchlorophyll-based pigments found in cyanobacteria and eukaryotic algae. The phycobiliproteins have characteristic broad absorption profiles spanning 450-600 nm, emissions ranging 570-660 nm, and small stokes shifts see Fig. 3. The major structural subunits, phycoerythrobilin (PEB) or phycocyanobilin... 

C-Phycocyanin is abundant in blue-green algae. Nearly 99% deuterated samples of this phycobiliprotein were isolated from the cyanobacteria that were grown in perdeuterated cultures [46] (99% pure D2O) at Argonne National Laboratory. This process yielded deuterated C-phycocyanin proteins (d-CPC) that had virtually all of the H—C bonds replaced by H—C bonds. One can obtain a lyophilized sample that is similar to amorphous solids as determined by neutron diffraction [43]. As it has been defined in previous papers [47-49], the level of hydration h = 0.5 corresponds to 100% hydration of C-phycocyanin, which leads to a coverage of about 1.5 monolayers of water molecules on the surface of the protein [50]. 

WA Sidler (1995) Phycobilisome and phycobiliprotein structures. In DA Bryant (ed) Molecular Biology of Cyanobacteria, pp 139-216. Kluwer... 

CYANOBACTERIA/ Cyanophyta/ Cyanophyceae Cyanobacteria PA blue-green algae , mostly contain phycobiliprotein filiamentous or otherwise colonial Oscillatoriales and heterocystous Nostocales include N-fixers picoplanktonic members in Chroococcales and Chloroxybacteria (without phycobiliprotein) Trichodesmium, Synechococcus, Prochlorococcus... 

Cyanobacteria - picoplanktonic, phycobiliprotein A 50 - 1 ++ small size, good nutrient uptake... 

There are few examples in the microchip literature that feature analytes of interest exhibiting native fluorescence, such as the phycobiliproteins present in cyanobacteria and some algae." " Recently,... 

Substantial quantities of edible cyanobacteria are produced globally to meet the high demands of both food and pharmaceutical industries. These cyanobacteria contain substantial quantities of phycobiliproteins, of which phycocy-anin, in particular, has various therapeutic effects owing to the linear tetrapyrrole chromophore phycocyanobilin. Cyanobacteria can also synthesize macrocyclic tetrapyrrole corrinoid compounds. However, various edible cyanobacteria contain substantial quantities of inactive pseudo-Bi2 rather than active Bi2- To overcome this nutritional defect of edible cyanobacteria, it is vital to determine the genetic, biochemical, and physiological properties of pseudo-Bi2-... 

Very pure preparations of heterocysts of Nostoc ATCC 29150 lacked PSn activity as measured by oxygen evolution and by fluorescence induction. The absence, in this strain, of phycobiliproteins is consistent with inactive PSII. Others have reported phycobiliproteins in some strains of cyanobacteria (7,8) thus, their presence may depend on the strain or on the conditions of growth. Although there is no functional PSn, the proteins of the complex are present in heterocysts, and fluorescence spectra indicate that chlorophyll may be bound to CP47. 

Phycobilisomes (PBsomes) constitute the light-harvesting antennae of cyanobacteria. Most of them are made up of a central three-cylinder core from which six rods radiate (1). However, exceptions have been described i) Synechococcus sp. PCC 6301 and 7942 have hemidiscoidal PBsomes, but the six rods radiate from a core made up of only two cylinders (2) ii) according to the observed ratio of rod phycobiliproteins (PB) versus core PBs, as well as to electron microscopy studies, Phormidium sp. PCC 7376 seems to have PBsomes resembling more closely the hemi-ellipsoidal tyjpt described for most of the rhodophytes (3) iii) finally, Gloeobacter violaceus, which does not have classical thylakoid membranes, harbors very peculiar rod-shaped PBsomes directly attached to the cytoplasmic membrane (4). 

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