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: j-kell...@northwestern.edu
*******************************************
----- Original Message -----
From: "Matthew Alan Bratkowski" <mab...@cornell.edu>
To: <CCP4BB@JISCMAIL.AC.UK>
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: j-kell...@northwestern.edu
*******************************************
