[Chimera-users] coloring individual segments of a protein

[Elaine Meng]

Hello AG,
There are several ways.  I’ll try to outline the main ones:

(A) Use the "rainbow command  with the “sse” option to automatically assign a different color for each secondary structure element (SSE, e.g. helix and/or strand).
<http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/rainbow.html>

By “automatically” I mean that you don’t name each color yourself.  Instead Chimera interpolates within the specified color range to give each SSE a separate color.  It doesn’t color the coil between SSEs. Example commands (use Favorites menu to show Command Line):

color gray coil
rainbow sse
rainbow sse orange,white,cyan #0

… where the second example goes through orange, white, and cyan instead of the default rainbow colors, and only affects model #0 (see command-line specification <http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/frameatom_spec.html>).  As explained in the “rainbow" manual page linked above, you could use “helix” or “strand” instead of “sse” to color only the helices or strands, respectively. If you don’t use any of those, the color will be different for each residue and gradually change within each SSE.

(B) If you want to control the specific color for each SSE yourself, you would have to do a separate coloring step for each SSE. You could select the residues of the SSE and then use Actions… Color in the menu or a command to color the selection, for example:

color red sel
color purple,r sel
… where the second example “,r” means ribbon-only. 

A convenient way to select an individual SSE is by showing the protein sequence (menu Favorites… Sequence) and then in the sequence window, dragging a box to select an SSE.  The light yellow and light green boxes in the sequence window show where each SSE starts and ends.  

However, if you already knew the residue numbers and were using commands, you could specify the residues directly instead of selecting them, for example:

color cyan,r :50-64.A
… to color ribbons-only of residues 50-64 in chain A

Color command:
<http://www.rbvi.ucsf.edu/chimera/docs/UsersGuide/midas/color.html>

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 Apr 14, 2015, at 7:47 AM, A G Szabo <agszabo at bell.net> wrote:

> How do I use Chimera to color a protein in the following way: for example:
> Helix 1 -  red
> Helix 2 – yellow
> Helix 3 – magenta
> Strand 1 – dark blue
> Strand 2 – cyan
>  
> Etc.
>  
> A G Szabo