I second Jim’s suggestion of concentrating the protein. You should see a third to half of your crystallization drops produce precipitant. If you are below that your concentration is too low. Most of our structural genomics targets crystallize at concentrations above 20 mg/mL and several as high as 75-100 mg/mL.

Thomas Edwards

Emerald BioStructures

Seattle Structural Genomics Center for Infectious Disease (SSGCID)

From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Jim Pflugrath
Sent: Friday, March 05, 2010 8:10 AM
To: [log in to unmask]
Subject: Re: [ccp4bb] crystallization of a macromolecular complex

20 g/L is the same as 20 mg/ml, isn't it?  That does not seem particularly high to me.

Why not try 200 g/L?

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From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Jan Rash
Sent: Friday, March 05, 2010 8:03 AM
To: [log in to unmask]
Subject: [ccp4bb] crystallization of a macromolecular complex

Dear All,

This is about the crystallization of the macromolecular complex which is highly soluble and shows no signs of the aggregation (even at high concentration). We have tried several salts, precipitants and even high protein concentration (around 20g/L) for its crystallization without any genuine hit. Any suggestions for growing the crystals of this macromolecular complex will be highly appreciated.

Thanks,

Jan