Re: [ccp4bb] Protein concentration vs Molecular wt...

2012-07-20 Thread Oganesyan, Vaheh
to:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Roger Rowlett Sent: Thursday, July 19, 2012 4:42 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Protein concentration vs Molecular wt... This is almost exactly our basic approach, too. Before we got a dropsetter, we did 24 wells (1/2 screen) to get a fee

Re: [ccp4bb] Protein concentration vs Molecular wt...

2012-07-20 Thread Patrick Shaw Stewart
See http://www.douglas.co.uk/PDB_data.htm, section 4 On 19 July 2012 20:58, james09 pruza wrote: > Dear Crystallographers, > Is there any rule of thumb for Protein concentration and molecular weight > for crystallization trials of a soluble protein? Looking for high molecular > wt. protein ~50

Re: [ccp4bb] Protein concentration vs Molecular wt...

2012-07-19 Thread Tom Murray-Rust
Hi James, You can get the PCT (Pre-Crystallisation Test) from one of the more famous manufacturers of crystallography products - essentially you can quickly screen your protein to get an idea if it is too dilute, too concentrated, or somewhere in the middle. Of course, the results are representati

Re: [ccp4bb] Protein concentration vs Molecular wt...

2012-07-19 Thread Roger Rowlett
This is almost exactly our basic approach, too. Before we got a dropsetter, we did 24 wells (1/2 screen) to get a feel for the correct protein concentration. Some additional rules of thumb we use: 1. We usually start at 10 mg/mL protein and go up or down from there depending on the results o

Re: [ccp4bb] Protein concentration vs Molecular wt...

2012-07-19 Thread mjvdwoerd
I don't think there is such a rule, but in the old days, when we only had Hampton Screen I and II, the rule was: - Set up screen 1, look at the drops and you should expect some kind of precipitation in 50% of the drops. If much less than that, increase your protein concentration. If much more t