Hi Bala, This is an expected behavior of Chimera: the ribbon is a smoothed path that does not go exactly through the atom positions. When ribbon is shown, the default is to simply draw the longer or shorter bonds where the ribbon is farther from or closer to the displayed atoms (ribose/base or amino acid side chain) than are the backbone atoms that the ribbon represents. However, there are ways to change the behavior: (A) use the command "ribbackbone" to allow display of both backbone atoms and ribbon. This will not make any bonds look longer or shorter, but it is usually ugly because the ribbon is not in the same place as the backbone atoms. http://www.cgl.ucsf.edu/chimera/docs/UsersGuide/midas/ribbackbone.html (B) with Ribbon Style Editor, "Residue Class" section, you can set which atoms control the ribbon path and which are hidden automatically (by default, without using "ribbackbone") when ribbon is shown: http://www.cgl.ucsf.edu/chimera/docs/ContributedSoftware/ribbonstyle/ ribbonstyle.html I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. meng@cgl.ucsf.edu UCSF Computer Graphics Lab and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco http://www.cgl.ucsf.edu/home/meng/index.html P.S. you can send attachments such as images to chimera-users, but the message will not appear until the moderator has a chance to approve it... just be patient and it will be sent! On Mar 2, 2008, at 9:00 PM, bala wrote:

-----Original Message----- From: bala Sent: Fri 2/29/2008 12:13 PM To: chimera-users@cgl.ucsf.edu Subject: longer bonds in image

Hi all,

Thank you for the suggestions for my previous query.

When the ribbons are displayed for the backbone of a RNA molecule. Some of the bonds look longer than usual. Herewith i have attached the image of a RNA molecule in which residues colored in cyan have some bonds longer in appearance. Kindly help me to get this of this.

Thanks, Bala