X-ray crystallographic studies on C-phycocyanins from cyanobacteria from different habitats: marine and freshwater

Satyanarayana, L. ; Suresh, C. G. ; Patel, A. ; Mishra, S. ; Ghosh, P. K. (2005) X-ray crystallographic studies on C-phycocyanins from cyanobacteria from different habitats: marine and freshwater Acta Crystallographica Section F, 61 (9). pp. 844-847. ISSN 1744-3091

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Official URL: http://scripts.iucr.org/cgi-bin/paper?za5111

Related URL: http://dx.doi.org/10.1107/S1744309105025649


C-phycocyanins from three cyanobacterial cultures of freshwater and marine habitat, Spirulina, Phormidium and Lyngbya spp., were purified to homogeneity and crystallized using the hanging-drop vapour-diffusion method. Blue-coloured crystals in different crystal forms, monoclinic and hexagonal, were obtained for the three species. The crystals took 1-12 weeks to grow to full size using polyethylene glycols of different molecular weights as precipitants. The amino-acid sequences of these proteins show high similarity to other known C-phycocyanins from related organisms; however, the C-phycocyanins reported here showed different biochemical and biophysical properties, i.e. molecular weight, stability etc. The X-ray diffraction data were collected at resolutions of 3.0 Å for the monoclinic and 3.2 and 3.6 Å for the hexagonal forms. The unit-cell parameters corresponding to the monoclinic space group P21 are a = 107.33, b = 115.64, c = 183.26 Å, β = 90.03° for Spirulina sp. C-phycocyanin and are similar for crystals of Phormidium and Lyngbya spp. C-phycocyanins. Crystals belonging to the hexagonal space group P63, with unit-cell parameters a = b = 154.97, c = 40.35 Å and a = b = 151.96, c = 39.06 Å, were also obtained for the C-phycocyanins from Spirulina and Lyngbya spp., respectively. The estimated solvent content is around 50% for the monoclinic crystals of all three species assuming the presence of two hexamers per asymmetric unit. The solvent content is 66.5 and 64.1% for the hexagonal crystals of C-phycocyanin from Spirulina and Lyngbya spp. assuming the presence of one monomer per asymmetric unit.

Item Type:Article
Source:Copyright of this article belongs to John Wiley and Sons.
Keywords:Cyanobacteria; C-phycocyanin
ID Code:60279
Deposited On:08 Sep 2011 13:27
Last Modified:08 Sep 2011 13:27

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