It is always worth doing a anomalous difference Fourier especially with such high resolution data. Very easy if you are using CCP4 GUI2 - just ask for it as part of your refinement run.
It is likely the high peaks could be S - but you can check by comparing their height to that of a MET S peak . But remember MET are often somewhat floppy and may well be less well resolved.. Eleanor On 4 February 2017 at 19:40, Artem Evdokimov <[email protected]> wrote: > Hard to see but maybe a transesterified serine like ser-o-AMP > > Can you share the nature of the enzyme? > > Artem > www.harkerbio.com > "Zoidberg was here" > > > > > On Feb 4, 2017 10:14 AM, "sharifah nur hidayah syed mazlan" < > [email protected]> wrote: > >> Dear All, >> >> I am working on a structure with an unknown blob extended from the gamma >> O of the catalytic serine residue. The resolution of the dataset is 1.38 A. >> I have no idea whether the residue is modified or the blob belongs to other >> molecule. >> >> The protein was expressed in Rosettagami (DE3), purified using >> Ni-Sepharose (affinity chromatography) and Q-Sepharose (Anion exchange >> chromatography). The crystallization formulation used contain 15% PEG 8000, >> 0.2 M Ammonium sulphate, 0.1 M sodium cacodylate trihydrate pH 6.5; and the >> buffer composed of 50 mM Sodium chloride and Phosphate buffer pH 8. No >> protease inhibitor was used (eg: PMSF) >> >> I have tried to fit in diethylene glycol as shown in one of the attached >> figures, but as observed, it is not really fit and the molecule is in >> incorrect conformation. >> >> Kindly help me with this matter. >> >> >> >> Thanks and regards, >> >> Sharifah Nur Hidayah >> Universiti Putra Malaysia, >> Malaysia >> >> >>
