You might get better help if you post links (not attachments) to diffraction images from several angles and an image of the crystal that gave the image, and maybe several images of typical crystals.
Also, you could post dimensions of the crystal, and if your lab is set up for it, a picture of the crystal in the loop. 4 Å diffraction for a plate crystal could be promising, but plate crystals require proper handling and optimization. You should also try to work with your 4 Å data and see if you can get a structure with MR (or even MIR), if that is at all possible. You might find that you can trim some extra sequence from one or both ends that hinder good crystallization. James On Oct 15, 2012, at 4:01 PM, Jahan Alikhajeh wrote: > > Dear Friends, > > I am trying to crystalize a 70 kDa nasty protein but I got plate shape > crystals with high mosaicity and useless diffraction (up to 4A). > I tried to improve/optimize crystallization but either I got the same or > nothing. I tried seeding but I had so many crystals without any improvement. > Does anyone have better idea than routine optimization method in the lab? > Thanks in advance. > > Jahan