Tom and Elaine, Is there a simple way to manipulate part of a protein structure in Chimera? What I would like to do is the following. Let's say I have a molecular compose 8 helixes. 7 of them fit in the cryo-EM map perfectly but one short helix is off probably owing to conformational change. I would like to move the short helix into the density map manually. The difficult part is how to make a smooth transition for loop regions at both ends of the helix. Would you please give me some advice on this? Thanks! Haixin -- Haixin Sui, Ph.D. Wadsworth Center NYS Dept. of Health Empire State Plaza P.O. Box 509 Albany, NY 12201-0509 (518)474-4235 (office) (518)473-0309 (lab) IMPORTANT NOTICE: This e-mail and any attachments may contain confidential or sensitive information which is, or may be, legally privileged or otherwise protected by law from further disclosure. It is intended only for the addressee. If you received this in error or from someone who was not authorized to send it to you, please do not distribute, copy or use it or any attachments. Please notify the sender immediately by reply e-mail and delete this from your system. Thank you for your cooperation.