Dear All, I have a 3.3 A data for a protein whose SG is P6522. Model used was wild type structure of same protein at 2.3 A. After molecular replacement, first three rounds of refinement the R/Rf was 26/32.8, 27.1/31.72 % and 7.35/30.88 % respectively.In the fourth round I refined with TLS and NCS abd added water and the R/Rf dropped to 19.34/26.46. It has almost 7% difference. I also see lot of unanswerable density in the map where lot of waters were placed. Model fits to the map like a low resolution data with most of side chains don't have best density. I was not expecting such a sudden drop in the R/Rfree and a difference is 7.2%. I am wondering if I am in right direction. I am not sure if this usual for 3.3A data or in general any data if we consider the difference. I appreciate your valuable suggestions. ThanksRaj
