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 <[email protected]>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:[email protected]] *On Behalf Of > *Matthew > Bratkowski > *Sent:* Tuesday, November 16, 2010 7:58 PM > *To:* [email protected] > *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: [email protected] http://crg.ubc.ca/VanPetegem/
