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The selenium-containing phycocyanin from the selenium-rich algae (Spirulina platensis) has been crystallized in two crystal forms by the hanging-drop vapor diffusion techniques. A chro-matographic procedure of gel filtration and anion exchange was used for purification. Form I crystal with space group P21 and cell parameters a =108.0 A, b = 117.0 A, c = 184.0 A, β = 90.2° and 12(αβ) units in the asymmetric unit was obtained by using (NH4)2SO4 as precipitant. These crystals diffract up to 2.8 A. Form II crystal obtained by using PEG4000 as precipitant belongs to space group P63 with unit cell constants a = 155.0 A, c = 40.3 A, γ=120.0° and one(αβ) unit in the asymmetric unit. The crystals diffract beyond 2.9 A. The possible stacking forms of phycocyanin molecules in the first crystal form were discussed.
The selenium-containing phycocyanin from the selenium-rich algae (Spirulina platensis) has been crystallized in two crystal forms by the hanging-drop vapor diffusion techniques. A chro-matographic procedure of gel filtration and anion exchange was used for purification. Form I crystal with space group P21 and cell parameters a = 108.0 A, b = 117.0 A, c = 184.0 A, β = 90.2 ° and 12 (αβ) units in the asymmetric unit was obtained by using (NH4) 2SO4 as precipitant. These crystals diffract up to 2.8 A. Form II crystal obtained by using PEG 4000 as precipitant belongs to space group P63 with unit cell constants a = 155.0 A, c = 40.3 A, γ = 120.0 ° and one (αβ) unit in the asymmetric unit. The crystals diffract beyond 2.9 A. The possible stacking forms of phycocyanin molecules in the first crystal form were discussed.