Dear Tiancen, for a survey of post-crystallization options, I highly recommend the following review article:
Heras B, Martin JL. 2005 Post-crystallization treatments for improving diffraction quality of protein crystals. Acta Crystallogr D Biol Crystallogr. 61, 1173-80. best of luck Savvas Quoting Tiancen Hu <[EMAIL PROTECTED]>: > Dear all, > > Sorry for the non-CCP4 question. I think this is an old story but our > knowledge to deal with it is very limited. So any suggestions will be greatly > appreciated. > > We have crystallized a 21KD protein with 2 disulfide bonds grown for one > month in 0.1M tri-sodium citrate pH 5.6, 0.5M (NH4)2SO4 and 1M Li2SO4. The > crystals look big (~0.4mm x 0.4mm x 0.3mm) and pretty (sharp edge, clean > surface) but diffracted to only 4A in-house. The spots are quite strong and > isotropic at low resolution but decay sharply beyond 5-6A. The crystal > belongs to P4 pointgroup (P422 is also possible) with cell parameters of > 127.6, 127.6, 162.5, 90, 90, 90. The solutions we can think of to elevate its > diffraction ability are as follows: > > 1) Try synchrotron radiation > 2) Try a lot of similar crystals and hope one of them diffracts better than > others > 3) Let the crystals grow for a longer time and hope it could pack more > ¡°orderly¡± > 4) Additive screen based on the original condition > 5) Check the original plates for other crystallizing conditions > (unfortunately until now this is the only one out of ~300) > 6) Screen with other forms of the protein, i.e., N/C-terminus truncated > ones, > complexed with its ligands etc. > > I believe many protein crystallographers have encountered similar problems, > are there any successful stories from these fancy poor crystals? Any > suggestions or references will be highly appreciated. > > Thanks in advance! > > Tiancen Hu > Shanghai Institute of Materia Medica > Rm. 2107, #555, ZuChongzhi Rd. > Shanghai 201203 > P.R. China > Tel: +86-21-50806600 ext 2107 > Email: [EMAIL PROTECTED] > > --
