Cartoon

Cartoon Command

DESCRIPTION

cartoon changes the default cartoon for a set of atoms.

USAGE

cartoon type, (selection)

type = skip | automatic | loop | rectangle | oval | tube | arrow | dumbbell

PYMOL API

cmd.cartoon(string type, string selection )

EXAMPLES

cartoon rectangle,(chain A)
cartoon skip,(resi 145:156)

NOTES

the "automatic" mode utilizes ribbons according to the information in the PDB HELIX and SHEET records.

Adjusting width of cartoon

Try varying the following.

For β-strands:

cartoon_rect_length
cartoon_rect_width

For α-helices:

cartoon_oval_length
cartoon_oval_width

For loops:

cartoon_loop_radius

For "fancy" α-helices:

cartoon_dumbell_length
cartoon_dumbell_width
cartoon_dumbell_radius  (radius of cylinder at edge of helix ribbon)

In each case "length" refers to what some might call the width and "width" refers to what some might call the thickness.

Cartoon Representation Example

Forcing Exact Boundaries in Coloring Secondary Structures

To force PyMol to respect secondary structural elements color-wise (PyMol smooths out colors near color chagnes for a prettier image) use the following PyMol command: set cartoon_discrete_colors, on

Discrete Coloring Off

Discrete Coloring On

Sausage Representation

The familiar sausage representation in PyMol is called, "putty". To enable the putty/sausage view simply do,

show cartoon
cartoon putty
unset cartoon_smooth_loops
unset cartoon_flat_sheets

As of v 0.98 or so, there's a Putty option. Use this.

Example of B-factor Putty

Black and White Representation

UPDATE: This method is essentially obseleted by the new setting set ray_trace_mode,2. More information on this at Ray. For those who want a nifty black and white representation of their protein try the following:

1. Ray trace your protein of choice in a cartoon representation use a BLACK background
2. Save the image
3. Load the image in GIMP.
   

   Black BG Ribbon
4. Desaturate or Grayscale the image.
   

   Grayscale
5. Run the filter: Filter->Edge-Detect->Edge.
   

   Edge Detect
6. Select: Layers->Color->Invert.
   

   Invert Color
7. Different methods of edge detection will give you different results. In the last example, I used Laplace Edge-Detect, then painted an all white layer beneath the current layer to achieve the results.
   

   Comments

I'm sure there are other ways to do this. If you want to include it in a publication make sure you ray traced it large enough. For that, see Creating Publication Quality Images.

CA (Alpha Carbon) Trace

If you have a structure with just a alpha carbon trace, you can get a cartoon by

set cartoon_trace,1
show cartoon

If your structure is more than just the CA backbone, the cartoon representation will look incorrect, so use it just with CA trace.

Various Transparency Levels

Example of Cartoon Multi-level Transparency. The near cartoon has transparency setting 0.2, the segment in the BG 0.5.

One can make different cartoon selections have different transparency values, in PyMol. The trick here is to use "create" instead of "select". Create makes new objects that can have independent settings.

load mol_obj.pdb

# transfer a piece of the molecule into a new object

create new_obj, chain A
remove mol_obj in new_obj

# adjust trasparency for the new object

set cartoon_transparency, 0.5, new_obj

Nucleic Acid Representation

Showing Nucleic Acids

To show nucleic acids in a nicer format do:

 set cartoon_ring_mode,1
 show cartoon

Other Nucleic Acids & Cartoon Settings

Here are some things to try:

set cartoon_ring_mode, 1   # (or 2 or 3)
set cartoon_ring_finder, 1 # (or 2 or 3 or 4)
set cartoon_nucleic_acid_mode, 0   # (or 1 or 2 or 3 or 4)

set cartoon_side_chain_helper
rebuild

set cartoon_ring_transparency, 0.5

set cartoon_ladder_mode, 0 # or 1

set cartoon_ladder_color, color-name
set cartoon_nucleic_acid_color, color-name

cartoon oval
set cartoon_oval_width, 0.8

cartoon rect

cartoon dumbbell
set cartoon_dumbbell_width, 0.4
set cartoon_dumbbell_radius, 0.4

Examples of nucleic acid cartoons

See Also

Displaying_Biochemical_Properties