[ccp4bb] Differentiate salt and protein crystals
Hi all. I set up some trays of membrane protein remotely in cubic phase. I don't have ready access to them so I can't shoot/pick the crystals. Under polarising lights, some crystals appears coloured across many conditions, making me think these are salt. Is there some knowledge of inorganic chemistry that be relied to prioritise some for reproductions at my lab? Can detergents crystallise and produce colours under polarising light? Thank you. Theresa
Re: [ccp4bb] Differentiate salt and protein crystals
Hi Theresa, Your observation of colored crystals under polarising lights seems odd to me. I assume your protein should be colorless and under normal light these crystals are colorless? Are these trays set up in glass plate or plastic plates? If you are willing to upload some pictures, I might be able to tell you whether they are salt crystals or not. Regards Jingquan On 15 March 2012 15:43, Theresa H. Hsu theresah...@live.com wrote: Hi all. I set up some trays of membrane protein remotely in cubic phase. I don't have ready access to them so I can't shoot/pick the crystals. Under polarising lights, some crystals appears coloured across many conditions, making me think these are salt. Is there some knowledge of inorganic chemistry that be relied to prioritise some for reproductions at my lab? Can detergents crystallise and produce colours under polarising light? Thank you. Theresa
Re: [ccp4bb] Differentiate salt and protein crystals
The best reproduction I can suggest would be to setup one or two LCP experiments exchanging the protein for its buffer. If you get crystals, you know for sure they're not protein. Cheers, Jon 2012/3/15 Theresa H. Hsu theresah...@live.com Hi all. I set up some trays of membrane protein remotely in cubic phase. I don't have ready access to them so I can't shoot/pick the crystals. Under polarising lights, some crystals appears coloured across many conditions, making me think these are salt. Is there some knowledge of inorganic chemistry that be relied to prioritise some for reproductions at my lab? Can detergents crystallise and produce colours under polarising light? Thank you. Theresa -- Dr. Jon Agirre Postdoctoral Scientist - Protein and Virus X-ray Crystallography Group Biophysics Unit (CSIC-UPV/EHU) +0034946013357
Re: [ccp4bb] Differentiate salt and protein crystals
On Thu, Mar 15, 2012 at 11:14 AM, Jon Agirre jon.agi...@gmail.com wrote: The best reproduction I can suggest would be to setup one or two LCP experiments exchanging the protein for its buffer. If you get crystals, you know for sure they're not protein. It should be pointed out that the converse is not true: if you don't get crystals from buffer-only crystallizations, it doesn't mean that your putative protein crystals are really protein. Jacob Cheers, Jon 2012/3/15 Theresa H. Hsu theresah...@live.com Hi all. I set up some trays of membrane protein remotely in cubic phase. I don't have ready access to them so I can't shoot/pick the crystals. Under polarising lights, some crystals appears coloured across many conditions, making me think these are salt. Is there some knowledge of inorganic chemistry that be relied to prioritise some for reproductions at my lab? Can detergents crystallise and produce colours under polarising light? Thank you. Theresa -- Dr. Jon Agirre Postdoctoral Scientist - Protein and Virus X-ray Crystallography Group Biophysics Unit (CSIC-UPV/EHU) +0034946013357 -- *** Jacob Pearson Keller Northwestern University Medical Scientist Training Program email: j-kell...@northwestern.edu ***
