2uun

[[Image:2uun.jpg|left|200px]]

'''CRYSTAL STRUCTURE OF C-PHYCOCYANIN FROM PHORMIDIUM, LYNGBYA SPP. (MARINE) AND SPIRULINA SP. (FRESH WATER) SHOWS TWO DIFFERENT WAYS OF ENERGY TRANSFER BETWEEN TWO HEXAMERS.'''

==Overview==

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 A for the monoclinic and 3.2 and 3.6 A for the hexagonal forms. The unit-cell parameters corresponding to the monoclinic space group P2(1) are a = 107.33, b = 115.64, c = 183.26 A, beta = 90.03 degrees for Spirulina sp. C-phycocyanin and are similar for crystals of Phormidium and Lyngbya spp. C-phycocyanins. Crystals belonging to the hexagonal space group P6(3), with unit-cell parameters a = b = 154.97, c = 40.35 A and a = b = 151.96, c = 39.06 A, 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 alphabeta monomer per asymmetric unit.

2UUN is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Leptolyngbya_sp. Leptolyngbya sp.]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2UUN OCA].

X-ray crystallographic studies on C-phycocyanins from cyanobacteria from different habitats: marine and freshwater., Satyanarayana L, Suresh CG, Patel A, Mishra S, Ghosh PK, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2005 Sep 1;61(Pt, 9):844-7. Epub 2005 Aug 31. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/16511175 16511175]

[[Category: Single protein]]

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