Dear Colleagues, I am refining a structure and there is a SO4 on the 3-fold axis. What I did was to put atom S and O1 on the 3-fold with occ=0.33, and O2 with occ=1, and no O3 and O4 in the pdb (O3 and O4 will be the symmetry of O2). But when I refine it, Phenix complains close non-bounded distances for both S and O1. Is there a way to refine this sulfate? Thanks! Best regards, Tongqing Tongqing Zhou, Ph.D. Staff Scientist Structural Biology Section Vaccine Research Center, NIAID/NIH Building 40, Room 4609B 40 Convent Drive, MSC3027 Bethesda, MD 20892 (301) 594-8710 (Tel) (301) 793-0794 (Cell) (301) 480-2658 (Fax) ****************************************************************************** The information in this e-mail and any of its attachments is confidential and may contain sensitive information. It should not be used by anyone who is not the original intended recipient. If you have received this e-mail in error please inform the sender and delete it from your mailbox or any other storage devices. National Institute of Allergy and Infectious Diseases shall not accept liability for any statements made that are sender's own and not expressly made on behalf of the NIAID by one of its representatives. ******************************************************************