From: Mario Sniady [mailto:[email protected]] Sent: Wednesday, August 08, 2012 7:56 AM To: [email protected] Subject: [ccp4bb] Unexplainable Density
It looks like it could be citrate. Is there any possibility of that? John Andersen While building our crystal structure model we encountered density which we weren't able to assign. The unknown molecule/molecules seems to coordinate a Ni2+-ion. This ion is also coordinated by a histidin and probably one H2O-molecule. The crystals have been grown from a protein-complex including the carotinoid peridinin, the lipid DGDG and Chlorophyll. Besides this the solution in which they have been grown contains Tris pH 8.5, NiCl2 and PEG 2000 MME. The linked images show a rotation around the density in 90°-steps (1.1A, 1.2sigma contour level). The above mentioned H2O-molecule has been removed. It is supposed to fill the density that is below the Ni2+-Ion in the first picture. Images: http://www.bioxtal.rub.de/myst.html.en Any hints are welcome =) Mario
