[ccp4bb]: R and Rfree factor for 2.0 A model

[Wu Mousheng]

Dear all,   I am refining my model with 2.0A using CNS. I have fitted most of the protein sequence into the model (150 of 160 aa). I also added 100 water molecules into the model. The final R and Rfree factor are about 26% and 28%, respectively. I am wondering why I can not refine my model to low R and Rfree factors below 25%.  The geometry of my final model is very good. 96% residues are in most favorable region.   I think my data is quite good. I/sigma(unaverage) and completeness at highest resolution shell is 2.3 and 99%. Rmerge is about 6%. Redundancy is about 5.   Is my model acceptable based on the R and Rfree factors? Is there any reason for the high R and Rfree factors?   Thanks!   Best, Mousheng Wu, Institute of Molecular and Cell Biology, Singapore   DISCLAIMER: This email is confidential and may be privileged. If you are not the intended recipient, please delete it and notify us immediately. Please do not copy or use it for any purpose, or disclose its contents to any other person as it may be an offence under the Official Secrets Act. Thank you.