Hi, I'm having difficulty with performing TLS refinement on a highly symmetric system. The difference between the R_work and R_free increases with TLS refinement (16.5/21.4 changes to 14.4/22.2). The TLS tensors for some of the group are not sensible (if I understand the literature correctly) -there are some negative numbers for the T and L tensors (see below). The TLS groups were identified with phenix.find_tls_groups. Any suggestions would be appreciated. REMARK 3 SELECTION: chain 'A' and (resid 38 through 68 ) REMARK 3 ORIGIN FOR THE GROUP (A): 56.6459 -23.5648 -59.0695 REMARK 3 T TENSOR REMARK 3 T11: 0.2105 T22: 0.2895 REMARK 3 T33: 0.0962 T12: 0.0829 REMARK 3 T13: 0.0473 T23: 0.0007 REMARK 3 L TENSOR REMARK 3 L11: 0.0446 L22: 0.0120 REMARK 3 L33: 0.0096 L12: 0.0246 REMARK 3 L13: 0.0209 L23: 0.0106 REMARK 3 S TENSOR REMARK 3 S11: 0.0228 S12: -0.0268 S13: -0.0023 REMARK 3 S21: -0.0507 S22: 0.0526 S23: -0.0287 REMARK 3 S31: -0.0296 S32: -0.0137 S33: 0.0534? The data set is complete at 2.3Å resolution and there are no strange crystal phenotypes. Best wishes, Reza Reza Khayat, PhD Assistant Professor City College of New York Department of Chemistry New York, NY 10031