Hi Prem, The first thing I would do is to make certain that you really have prot+DNA crystals, and not DNA alone. If you can isolate enough crystals (you may need 15 or 30, depending on how large they are), SDS page would be informative. Run protein and DNA alone and together in the same gel as controls. This could save you a lot of time/effort since you don't want to optimize DNA-only crystals.
In any case, if it is the complex and still doesn't diffract well, I'd just start changing the DNA, both in length and sequence (the bases that don't matter for protein binding). Good luck, Greg On Apr 13, 2012, at 6:51 AM, Prem kumar wrote: > Hi all, > I got some Protein + DNA complex crystals (image attached) recently. > They are needle shape some times splitted chromosome type crystals. When we > pick long needles they bend so much than normal crystal but they dont break. > The small needle dissolve very fast as try to open the drop's film. we try to > diffract the long needle crystals and they diffract up to 20 A resolution. > Any suggestion how to improve those crystal packing. > > Thanks in advance! > -Prem > <IMG_1438.JPG> -- Department of Biophysics Johns Hopkins University 302 Jenkins Hall 3400 N. Charles St. Baltimore, MD 21218 Phone: (410) 516-7850 (office) Phone: (410) 516-3476 (lab) [email protected] http://www.jhu.edu/bowmanlab
