Rajesh; I am not sure that you have a high enough data:refinement parameters ratio to refine TLS. It just adds more parameters to refine that can lead to over-refinement of your model, especially at the 3.3 A.
HTH, Regina ________________________________ From: Rajesh kumar <ccp4...@hotmail.com> To: CCP4BB@JISCMAIL.AC.UK Sent: Friday, March 2, 2012 10:54 AM Subject: [ccp4bb] sudden drop in R/Rfree 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. Thanks Raj
