Dear Jobi, the paper of Heras and Martin 'Post-crystallization treatments for improving diffraction quality of protein crystals' is really helpful.
Additionally, if you have lysines have you tried reductive methylation? Good luck, e On Wed, April 13, 2011 12:34, Bingfa Sun wrote: > Dear Jobi, > > For a crystal which is big in size(0.2-0.3mm is pretty big) while diffract > poorly, dehydration (increase concentration of the precipitant slowly) is > a good choice to improve diffraction, especially for those tends to crack > during cryo. > > Also those regular optimization approaches: Additive screen etc. Sometimes > cleave the tag or change it to another end will work. > > Cheers, > > Bingfa > > > > 发件人: owner-ccp...@jiscmail.ac.uk [mailto:owner-ccp...@jiscmail.ac.uk] 代表 > Jobichen Chacko > 发送时间: 2011年4月13日 17:44 > 收件人: CCP4BB@JISCMAIL.AC.UK > 主题: [ccp4bb] Crystal Optimization > > > > Dear All, > > We got crystals for a 35 KDa protein with 323aa including His tag and > linker. It was originally crystallized in 0.1M BisTris Propane pH:6.5, > 0.2M Potassium thiocyanate and 20% PEG 3350. Later we managed to obtain > crystals with 0.1M BisTris pH:6.5, 0.2M Potassium thiocyanate and 20% PEG > 3350 as well. Crystals are 3 dimensional in shape and 0.2-0.3mm long. > Maximum resolution obtained till now is 5.8Å. Tried various cryo > conditions like Oil, glycerol, salt and sugars. However, the resolution > hasn't improved. The crystal tends to break in the presence of glycerol. > > Kindly give your suggestions to improve the resolution. > > Thanks. > > Jobi > > > > -- ************************************************** Eirini Gkougkoulia Department for Structural and Computational Biology Max F. Perutz Laboratories University of Vienna Campus Vienna Biocenter 5 A-1030 Vienna Austria
