Dear all, even though I checked the documentation and previous threads I didn't find something relative to my problem: I have an elongated e-density that looks like DTT and appears to be located on a special position (there is actually an axis betwenn C2 and C3 atoms of DTT). Refining with phenix.refine using either 0.5 or 1.0 occupancy, I am getting the DTT molecule outside the density (and the symmetry related DTT from the other side and still in the middle the strong difference density. thanks in advance for any suggestions-solutions Nikos -- --------------------------------- Dr. Nikos Pinotsis Section of Structural Biology Institute of Cancer Research Chester Beatty Laboratories 237 Fulham Road London SW3 6JB, UK Tel: +44 20 7153 5453 / 5447 --------------------------------- The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company Limited by Guarantee, Registered in England under Company No. 534147 with its Registered Office at 123 Old Brompton Road, London SW7 3RP. This e-mail message is confidential and for use by the addressee only. If the message is received by anyone other than the addressee, please return the message to the sender by replying to it and then delete the message from your computer and network.