Well it could be PEG, I have seen these things with rough edges/surface looks bit crystalline,but never diffracted. But it could be different in your case, can't say without much information.
Check if your protein sample to be pure ( impurities also influence crystal growth), or degradation of protein with time. based on your assumption if they are growing fast (means you also have high nucleation) reduce the protein/PEG and see how they influence these crystals. Make sure they are protein, if so additive screen may help. If they are protein crystals, it should/may crystallize in other conditions also. So keep screening simultaneously. You may try random microseeding with them. best On Wed, Dec 25, 2013 at 12:06 PM, Acoot Brett <acootbr...@yahoo.com> wrote: > Dear Puneet, > > My buffer contains high concentration of PEG, but no MPD and no volatile > compounds. > > Even some are spheres, clearly they are not phase separation. They can be > rather large, but the surfaces and edges looks etched, or as eroded., as if > destroyed by hard force. > > > > > On Wednesday, 25 December 2013 5:34 PM, Puneet juneja < > junejabiot...@gmail.com> wrote: > To slow down crystal growth, try setting plates at lower > protein/precipitant concentration, if u don't get crystals seeding at lower > protein or lower precipitant concentration might help. > > are these really protein crystals? ( U find the crystal, was there only a > single crystal). > > > sphere- is it like phase separation > Does your conditions have volatile compounds.? Or high concentration of > PEG or MPD. > > > > On Wed, Dec 25, 2013 at 5:49 AM, Acoot Brett <acootbr...@yahoo.com> wrote: > > Dear All, > > I am optimizing a crystal. In one of the optimizing conditions I find the > crystal is cubic-like shape (the crystal is not large, but absolutely not > the traditional "tiny crystal". The crystal has some kind of faces and > edges but not so sharp, and it is absolutely not round). But after 1 day > the crystal changed into sphere form (the "cubic" not obvious). > > Will you please introduce your experience on how to get the sharp face and > sharp edge crystal for my situation)? > > There is source says if the crystal grows too faster, the sharpness would > be lost. Will you please also let me know how to slow down the growth rate > of the crystal? > > Cheers, > > Acoot > > > > >
