Take one crystal and put it in mother liquor. Increase gradually (in two separately experiments) your ethanol and DMSO concentration (in my experience it could go up to 10%v/v after 1 week for some crystals) in order to find out the concentration that your crystal can stand without dissolve or crack. This gradual increase of EtOH or DMSO it is better to take place in days rather than hours. When you know the maximum EtOH and DMSO concentration you could repeat the experiment but this time you increase the substrate concentration and keeping DMSO and EtOH concentration in maximum that crystal can stand. For more details I recommend the following review.
McNae, I., et al Studying protein-ligand interactions using crystallography. Crystallography Reviews, 2005, 11, 61-71 Good luck George -----Original Message----- From: CCP4 bulletin board [mailto:[EMAIL PROTECTED] On Behalf Of David Briggs Sent: Saturday, October 11, 2008 8:12 AM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Substrate(water insoluble) Soaking Hi there... http://www.ncbi.nlm.nih.gov/pubmed/17164529 Hassell, AM et al, (2007) Crystallisation of Protein-ligand complexes Acta Cryst D63,p72 This paper is an excellent review of "how to get my ligand into my crystal" and includes some methods for dealing with insoluble ligands. HTH, David 2008/10/11 charliswu <[EMAIL PROTECTED]>: > > > > Hi All, > I am now soaking two substrates to the crystal.But one is soluble in > ethanol and one is soluble in DMSO. After co-crystallization and soaking, no > substrate found in the structure. > Does anybody has the experience in dealing this problem? > Any comments or suggestions would be highly welcome. > WuDong > IBP Beijing CAS > [EMAIL PROTECTED] -- ============================ David C. Briggs PhD Father & Crystallographer http://drdavidcbriggs.googlepages.com/home AIM ID: dbassophile ============================ No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.173 / Virus Database: 270.8.0/1717 - Release Date: 10/10/2008 4:08 ìì
