Hi Tiantian, it is pretty popular question. Here is copy-paste from my previous reply to similar question: """ a few things to consider: 1) Fourier truncation ripples: - CCP4 Newsletter http://www.ccp4.ac.uk/newsletters/newsletter42/content.html On the Fourier series truncation peaks at subatomic resolution Anne Bochow, Alexandre Urzhumtsev - Pages 52-55 here: http://www.phenix-online.org/presentations/latest/pavel_validation.pdf - Oliver Einsle, et al. Science, 1696 (2002) 297 - Page 267 Figure 4: Acta Cryst. (2004). D60, 260-274 2) Try: - refine individual anisotropic ADP for these atoms (and isotropic for the rest); - occupancy; - define charge in input PDB file; - if it is anomalous scatterer use and refine f' and f''. """ Hope this helps. Pavel.
Hi, I am dealing with a complex structure which the ligand contains a atom Iodine, I guess it's because Iodine is heavy atom, the electron density of Iodine turns red after 5 cycles refinement. Anybody coped with similar issue? How to let phenix know that the Iodine atom is part of the ligand?