Dear All I am sorry for the long context.
I have one protein (252 AAs, 2 Met) bound to double-stranded DNA (24 bp) crystalized. I collected the Se-Met data of the crystal in C222 up to 2.8 angstrom. the space group is confirmed by running the pointless. I used the Phenix.Autosol to find the heavy atoms and get a quite nice map after the density modification. It seems there are two proteins and two DNA duplex are in one ASU. Phenix.Autobuild can only build less than half of the protein sequence into the map and fill in the potential DNA map with amino acids. The Rwork/Rfree is 0.40 and 0.46, with the map CC=0.60. If I do the MR with the initial model built by Autobuild, the result TFZ=40, LLG=200+, which suggests the partial correction of the initial model. Here is the problem. From the map, I can see one of my protein domain and a clear feature of DNA double helix. But whatever I go further for manual build using coot, like building the DNA double-strand into the map and building the resolved domain, the refinement statistics go bad with R free ~0.50. I am wondering what's going wrong and how come the refinement can't improve the R factor. I have attached the relevant photos. https://drive.google.com/drive/folders/1dJ4kn7CEHkCL3sMcCJtBqa5OsVFQngBx?usp=sharing Sincerely Zhu ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
