Hi there, I'm trying to minimize a protein after mutating a residue with the Rotamers panel. I first do a Check Clashes and select the clashing atoms. Then I expand the selection using Zone to <5 A. I use these selected atoms as the non-fixed atoms and the unselected atoms as the fixed ones. When I then run the minimization with the appropriate settings, I get an RMSD of 0.000 A for each step, even though the step size is 0.02 A. Nothing moves. Same thing if I have no fixed atoms. Am I in a local minima? Is that why nothing moves? The energy is very high (from the Reply Log): Potential energy: 222274199.525130, Gradient norm: 833984762.552943 Updated 6029 atoms. RMSD: 0.000000 Finished 1 of 5 steepest descent minimization steps Any ideas? I do have some hetero atoms... Thanks, Darrell Darrell Hurt, Ph.D. Section Head, Computational Biology Bioinformatics and Computational Biosciences Branch (BCBB) OCICB/OSMO/OD/NIAID/NIH 31 Center Drive, Room 3B62B, MSC 2135 Bethesda, MD 20892-2135 Office 301-402-0095 Mobile 301-758-3559 http://bioinformatics.niaid.nih.gov (Within NIH) http://exon.niaid.nih.gov (Public) Disclaimer: 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.