Hi Vinson is O-glycosylation possible at all given the origin of the protein and the expression system used? best Savvas
On 24 Nov 2010, at 14:42, Vinson LIANG wrote: > Dear Savas and all, > > Thank you very much for all your quick suggestions. > > I have tried Tyr and it turns out to fit the density very well. I will have > the protein sequenced again to see if it is wrong sequece or O-linked > glycosylation. > > I'll let you know if it turns out to be O-linked glycosylation. > > All the best, > > Vinson > 发件人： Savvas Savvides <savvas.savvi...@ugent.be> > 收件人： Vinson LIANG <lwg_conrad_1...@yahoo.com.cn> > 抄 送： CCP4BB@JISCMAIL.AC.UK > 发送日期： 2010/11/24 (周三) 9:27:31 下午 > 主 题： Re: [ccp4bb] Strange density on Serine oxygen. > > Hi Vinson > Beyond the possibility for another type of residue as already suggested by > Phil and Mark, there is also the possibility of O-linked glycosylation of the > serine and threonine, if your protein undergoes such post-translational > modification and it has been expressed via an expression system that > processes the protein in that way. > Ser/Thr tandems are well known targets for O-glycosylation > (http://www.cbs.dtu.dk/databases/OGLYCBASE/). > > best regards > Savvas > > ---- > Savvas Savvides > Unit for Structural Biology @ L-ProBE > Ghent University > K.L. Ledeganckstraat 35, 9000 Ghent, Belgium > Ph. +32 (0)472 928 519 http://www.LProBE.ugent.be/xray.html > > > > On 24 Nov 2010, at 13:10, Vinson LIANG wrote: > >> Dear all, >> >> I'm refining a structure and find some strange triangle density on the >> oxygen of Ser and Thr at the C terminus. One picture of the strange density >> is attached here. Could anyone please give me some suggestions on what this >> could be? >> >> The buffer used during purification is PBS, Tris and NaCl. And >> crystallization condition contains PEG3,350 and Mg(NO3)2. >> >> Thank you all in advance for any suggestion. >> >> Best, >> >> Vinson Liang >> >> >> >> <triangle_density.gif> > > > > >
