Hi Jin, The text book might suggest metal ions, or even phosphorylation.....these do require evidence in the form additional structure beyond the metal or phosphorus though...
Bret On 4/09/10 9:53 AM, "Jin H. Park" <jinhp...@mail.med.upenn.edu> wrote: > > > Dear CCP4 community, > > > > I have solved the structure. But, there seems oddly strong density above > histidine residue. > What could this density be? > The protein was in Tris buffer, with NaCl and DTT, and crystallized in NaSCN > with PEG. > (electron density in the pictures is at 1.5 sigma) > > Thanks.