Hi John, There is "helix" and "strand" but no breakdown of the different subtypes of helix. To see the assignments on the sequence, use the Sequence tool (Favorites... Sequence). The light yellow boxes show helices, the light green boxes the strands. You can click on the boxes to select all residues in helices or all residues in strands. Also, you can use these terms as specifiers in the command line, for example color yellow helix select strand or from the menu, for example Select... Structure... secondary structure... helix I hope this helps, Elaine ----- Elaine C. Meng, Ph.D. UCSF Computer Graphics Lab (Chimera team) and Babbitt Lab Department of Pharmaceutical Chemistry University of California, San Francisco On Oct 8, 2009, at 6:35 AM, Beale, John wrote:

I realize that this is probably simple, but I haven’t been able to work this problem out.

Is there a way to read a single pdb file into Chimera and then have the program show me what amino acid sequences of the protein are alpha helices, what are beta sheets, and what are 3,10 helices, etc?

Thanks! John