Hi, I have noticed that Phenix mangles O-P bond lengths and angles in the phosphate groups of my DNA chain (example in pict attached). This only happens to 3 out of 28 phosphates. The refined protein-DNA structure does not present any other unusual stereochemistry issues and refinement runs normally. Could anybody advice on what is going on and how to fix this, please? I am using Phenix-1.7.3-928. Refinement is with default target weights, hydrogens on and does not include simulated annealing. I could make the stereochemistry targets more stringent, but the default values seem strict enough (bond and angle rmsd is 0.005 and 1.225). Thanks, Luca Luca Pellegrini Department of Biochemistry University of Cambridge 80 Tennis Court Road Cambridge CB2 1GA - UK Email: [email protected] Tel: 0044-1223-760469 Fax: 0044-1223-766002 Sanger building, room 3.59