Dear CCP4 community,

I wonder if anybody has experience about the color of GFP crystals. Is there any chance that the GFP crystal will become colorless? We are working on one membrane protein fused with GFP. Since we got some crystals which didn't show any color (Condition 01), I am not sure if I should go for optimization.

Please check the link below for the image details: http://www.docstoc.com/docs/55950590/GFP-crystals

Because of the limited amount of sample, we used Topaz system (screening chip) to do the screening and there is no way to confirm these crystals are actually protein crystals. I noticed that the crystals are bigger day by day. Is it a good sign to confirm the protein crystals? 

Thank you very much for your helpful information!