ribbons-demo -n calmod

Data Files:

The calcium binding protein calmodulin solved in this laboratory was taken from the Protein Data Bank (code is `3CLN'). The file was edited to remove all but the main reference and protein and calcium atoms and named `calmod.pdb'.

A secondary structure assignment was made based on H-bonding:
pdb-pro-pdb calmod.pdb calmod.ss

This file was then edited to replace the 'S' at the ends of the sheets with an 'A' to produce "arrows" on the sheet. ( at Babu's advice, set 26-28, 62-64, 99-101, 135-137 to sheets, and lengthened helices 4 and 6 by one residue, helix 8 by 2. )

The *.ribbons file consists of only one filename:
ls calmod.ss > calmod.ribbons

This file was then edited to add a special color file, `protein.color'.

The *.coords file consists of only one filename:
ls calmod.pdb > calmod.coords

The calcium atoms were separated placed in a separate file:
GREP HETATM calmod.pdb > calmod_cal.pdb

The calciums were turned into silver spheres (color-11)
pdb-range-sph calmod_cal.pdb calmod_cal.sph
( input line-1 at terminal: 1 4 11 )
( input line-2 at terminal: ctrl-D )

The *.atoms file consists of only one filename:
ls calmod_cal.sph > calmod.atoms

The cylinders to model the helix were created in several steps. First, a list was prepared of the residue ranges in the helices:
ss-hx-range calmod.ss calmod_hx.run

Next the alpha carbons in these ranges are fit to ideal helices:
pdb-hx-fit calmod.pdb calmod_hx.run > calmod_hx.fit

Finally the fit output is converted to bond format:
hx-dipole-cyl calmod_hx.fit calmod_hx.cyl

The *.bonds file consists of only one filename:
ls calmod_hx.cyl > calmod.bonds

The *.ss file was enhanced to include coloring by equivalent helices in the domains and by mainchain dihedral values.

The file calmod_hx.run was edited to chose colors for the ranges, then a new *.ss file was created (the old thrown replaced):
pdb-range-ss calmod.ss new.ss
mv new.ss calmod.ss

Next `rama' and `omega' keys were added:
pdb-rama-ss calmod.pdb calmod.ss

The *.model file was generated:
pdb-model calmod.pdb calmod.model

The protein ribbon model, plus atoms, plus `bonds' is now ready for display.

Image File: $RIBBONS_HOME/rgb/calmod.rgb

The model was displayed with default settings on the Ribbon Panel for everything except:
Chain Color = `15' (gold)
Helix Style = `Circle'
Coil Style = `Circle'
Ribbon Threads = `13'
Ribbon Samples = `13'
Sheet Width = `4.0'
Helix Width = `1.3'
Helix Depth = `1.3'
Coil Width = `1.7'
Coil Depth = `0.3'

The color #11 (silver) was modified with the Color Panel to add Blue Emission, to produce the glowing calcium atoms. The Geom Panel had the default settings except:
Sphere Radii = `1.25'
Bond Radii = `1.35'
Cylinder Depth = `24'

The image was then saved.


Ribbons User Manual / UAB-CMC / carson@cmc.uab.edu