There was a thread about this topic--dyes--a little while back. It seemed that many many dyes work, not just methylene blue. I believe there was even an over-the-counter mercury-bromine compound (merbromin?) which was suggested by Artem, as it would provide a nice derivative as well.
JPK On Tue, Nov 16, 2010 at 9:03 PM, Filip Van Petegem <filip.vanpete...@gmail.com> wrote: > One problem with a dye like methylene blue is that it tends to crystallize > in certain conditions commonly found in crystallization screens (e.g. some > that are high in PEG) making them less useful in such conditions. Has > anybody systematically tested alternative dyes and found one that is more > soluble? > Cheers > Filip Van Petegem > > > > On Tue, Nov 16, 2010 at 6:15 PM, Jim Pflugrath <jim.pflugr...@rigaku.com> > wrote: >> >> With Izit or other dyes, you might wish to do a positive control with bona >> fide protein crystals and a negative control with bona fide salt crystals. >> >> ________________________________ >> From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of >> Matthew Bratkowski >> Sent: Tuesday, November 16, 2010 7:58 PM >> To: CCP4BB@JISCMAIL.AC.UK >> Subject: Re: [ccp4bb] how to optimize small rod-shaped crystals >> >> I like using Izit dye from Hampton >> (http://hamptonresearch.com/product_detail.aspx?cid=4&sid=41&pid=33) to >> check if crystals are protein or salt. If the crystals are protein, the dye >> should absorb rather readily into the crystals and turn them blue, while the >> rest of the drop will eventually turn clear. Quite likely, excess dye will >> also crystallize out as well. Salt crystals will not soak in the dye, and >> the rest of the drop may remain blue for several days. >> Using Izit is easy and saves a lot of time. In my experience, I have >> gotten a lot of false positives from phosphate crystallization conditions, >> so you want to be sure that the crystals are not salt before you waste any >> time on optimizing them. >> Matt >> > > > -- > Filip Van Petegem, PhD > Assistant Professor > The University of British Columbia > Dept. of Biochemistry and Molecular Biology > 2350 Health Sciences Mall - Rm 2.356 > Vancouver, V6T 1Z3 > > phone: +1 604 827 4267 > email: filip.vanpete...@gmail.com > http://crg.ubc.ca/VanPetegem/ >
