On 10/02/11 16:56, Jacob Keller wrote:
Dear Crystallographers,
I would like to soak my crystals in bicarbonate (a possible
substrate), but the crystals have grown--and only grow--in pH 5.2-6.0,
so the bicarb/CO2 will just keep evolving out of the solution and
reliquishing its hydroxyls until
Hi Jacob, high-pressure cryocrystallography methods may be useful in this case.
I copied your question to Chae Un Kim here at MacCHESS and he forwards this
suggestion:
--
Hi Richard,
I think pressure cryocooling might be useful.
They may want to check
On Sun, 2011-10-02 at 15:56 -0500, Jacob Keller wrote:
Transfer them to higher pH, and hope
for the best?
Consider crosslinking your crystals with glutaraldehyde. They will then
became virtually insoluble, although it's possible that you may lose
diffraction at elevated pH.
--
Hurry up
PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Bicarb at low pH
Dear Crystallographers,
I would like to soak my crystals in bicarbonate (a possible
substrate), but the crystals have grown--and only grow--in pH 5.2-6.0,
so the bicarb/CO2 will just keep evolving out of the solution and
reliquishing
You can't change the pKa of CO2, which is 6.3. Any attempt to grow bicarb
complexes below pH 7.5 will be problematic due to CO2 bubble formation,
which may crack the crystal. What we do in these situations is to soak
crystals in a cryo solution at a higher pH for as long as practical, then
Jacob Keller wrote:
Dear Crystallographers,
I would like to soak my crystals in bicarbonate (a possible
substrate), but the crystals have grown--and only grow--in pH 5.2-6.0,
so the bicarb/CO2 will just keep evolving out of the solution and
reliquishing its hydroxyls until the pH is elevated
You might want to consider misusing the Xe-chamber which a couple of labs and
synchrotrons bought in the late 90's to derivative crystals with Xenon. Instead
of flushing the chamber with Xenon you could flush it with CO2 then plunge
freeze your crystals within the chamber.
careful
