I solved a structure in the presence of SAM, which is the same as SAH but
with a donor methyl group, and saw clear density for SAH, and not SAM, so it
seems that the SAM was either spontaneously de-methylated in solution, or
the protein which bound the SAM spontaneously demethylated it. In any case,
I remember having solubility issues with the SAH, but the SAM was fine. If
you are not particular which molecule you have (SAM vs. SAH), you might try
the SAM. Alternatively, you might just add SAH powder to the crystal mother
liquor, to get a saturated solution.
JPK
*******************************************
Jacob Pearson Keller
Northwestern University
Medical Scientist Training Program
Dallos Laboratory
F. Searle 1-240
2240 Campus Drive
Evanston IL 60208
lab: 847.467.4049
cel: 773.608.9185
email: [EMAIL PROTECTED]
*******************************************
----- Original Message -----
From: "Ray Changrui Lu" <[EMAIL PROTECTED]>
To: <CCP4BB@JISCMAIL.AC.UK>
Sent: Tuesday, November 06, 2007 12:48 PM
Subject: [ccp4bb] Dissolving s-adenosylhomocysteine
Hi all,
I am in the process of obtaining crystals in complex with
s-adenosylhomocysteine but this compound doesn't dissolve in normal
pH. The final concentration needs to be in mM range so the stock
ideally needs to be at least 50mM. I know SAH is quite soluble in DMSO
but is there anyway to get it in aqueous solution without organic
solvent or strong acid? Thank you very much in advance.
Ray
