Okay, it is wiki'd. Thanks Kay for pushing for this--it is the right thing
to do, and hopefully will be helpful for others in the future (and will
shorten the CCP4BB).
Jacob
*******************************************
Jacob Pearson Keller
Northwestern University
Medical Scientist Training Program
Dallos Laboratory
F. Searle 1-240
2240 Campus Drive
Evanston IL 60208
lab: 847.491.2438
cel: 773.608.9185
email: [log in to unmask]
*******************************************
----- Original Message -----
From: "Matthew Alan Bratkowski" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, April 21, 2009 11:09 PM
Subject: Re: [ccp4bb] Screening Condition Precipitates
> Hi.
>
> I noticed long, needle crystals in that very condition (A1 using the
> Molecular Dimensions kit) for the protein that I am working with one day.
> I tried to optimize that condition not long ago using reagents in my lab.
> I did not have a problem with precipitation until using high
> concentrations of Li2SO4 (I think 1 M or so). However, all of my effort
> was really just a waste of time. The next day, I looked back at the
> crystallization condition and discovered huge, identical crystals had
> formed in the reservoir as well. I'd say make sure that you actually have
> a protein crystal to begin with before optimizing, because it is likely
> that the crystal is
> just salt.
>
>
>> Hi All,
>>
>> there is a condition in the JCSG+ screen (0.2M Li2SO4, 0.1M NaOAc pH 4.5,
>> 50.0% v/v PEG-400) which forms heavy precipitate when made here in the
>> lab.
>> I assume that the order of addition of compounds might make a difference,
>> but doesn't this suggest that there is a high probabilty for salt
>> crystals
>> under these conditions? How stable can this solution be? An
>> anecdotes/advice
>> appreciated.
>>
>> I assume that the PEG makes Li2SO4 fall out of solution, or perhaps it is
>> the pH?
>>
>> Jacob Keller
>>
>> *******************************************
>> Jacob Pearson Keller
>> Northwestern University
>> Medical Scientist Training Program
>> Dallos Laboratory
>> F. Searle 1-240
>> 2240 Campus Drive
>> Evanston IL 60208
>> lab: 847.491.2438
>> cel: 773.608.9185
>> email: [log in to unmask]
>> *******************************************
>>
>
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