Hi, In addition to all great suggestions, I would try reductive lysine methylation (PMID 17098187). Good luck! Tomas
On Thu, Jan 21, 2021 at 6:46 PM Jon Cooper < 0000488a26d62010-dmarc-requ...@jiscmail.ac.uk> wrote: > > Hello, I always recommend limited chymotrypsinolysis. It's not a miracle cure but in a proportion of cases (~1/4?) it does work. > Cheers, Jon.C. > > > Sent from ProtonMail mobile > > > > -------- Original Message -------- > On 21 Jan 2021, 08:26, 商国辉 < sz20183020...@cau.edu.cn> wrote: > > > Hi,Everyone! > > Glad for me to ask us a question.Recently, I have optimized a solube protein crystal, and the crystal shape is like sea urchin at first. After I try different methods-Different Protein and Kit proportion 1:1 1.2:0.8 1.4:0.6,etc; try to add different additives and detergents ; different PEGs and salts; Seeding; Try different pH and PEG Concentrations orthogonally;change primary protein sequence and so on. And the crystal is plates, but still not a mono three-dimentional crystal, so I cannot solve the structure finally by the X-ray data. > > It is strange that the protein can only crystal in low salt concentration 60 mM-100 mM NaCl SEC Buffer(Superdex 200 buffer), as the salt concentration rises to 200 mM-1000 mM, the protein does not crystal at all, and the protein with Kit mixture is clear.So I use Superdex 200 to test the protein assembly using different salt concentration 60 mM/200 mM/1000 mM, the peak is moving to right as the salt concentration improve.So maybe the protein dimer form crystal(in 60 mM salt concentration). > > Here, I really need any available ideas for my protein crystal optimization, and I will spare no effort to solve the problems. Once I make it, I promise I would share my experiments for us to help anyone in the same situation.Figures and SD200 Peaks are below. > > Greatly thanks! > > Best Wishes. > > Sincerely ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
