Hi All, I would like to get some help from here for a data set I recently worked on. I have been working on a new kinase data set which does not have a close homolog. The data was collected to 2.1A resolution in space group P212121 however the difference between a and b is only 0.5A. If I index the data as P4, Rmerge is increased from 13% to 39%. I used the most close homologs which have about 37% sequence identity as search model for molecular replacement and it seemed I have got the solution by using Phaser with only the c-terminal part of the search model and also a long loop removed. After changed the different residues back to the target protein, the structure was refined to Rfree/R 46% and 43% to 2.1 A resolution. The existing c-terminal structure has well defined density except 25ish residue at the very c-terminal end doesn't have well connected density. Current model contains about 50% of overall target residues. I can see some extented difference density for several residues going to the N-terminal part and also extented density for the C-terminal loop for several residues. I also see tones of not well-conncted difference density in the N-terminal region. There was no sever clashes between molecules after mount all symmetry related molecules. My question is the following:
1. Have I got the correct solution for the molecular replacement? 2. How can I bring back the missing density for the N-terminal residues and the loop region? I would really appreciate any inputs or suggestions. Eric
