Colouring atoms, residues, molecules, etc. (COLOUR)

Introduction.

By default all atoms are blue, unless you give them a colour. Several WHAT IF options give other colours automatically. This then is either one colour for all atoms, or default colours.

If you use default atom colours (option COLATM) all nitrogens will be blue, oxygens red, carbons green, phosphors purple, and sulphers dirty yellow. See appendix B for the possible colours you can use.

In WHAT IF every atom has many parameters permanently attached to it, these parameters stay attached to the atom untill they are overwritten. One of these atomic parameters is the colour. The above mentioned default colours will be used for every atom send to the screen. The menu COLOUR allows you to change the colours of atoms (or whole residues).

If you use the command DIRECT in the GRAFIC menu, or click the DIRECT button in the row of boxes at the bottom of the screen, the so called direct mode is activated. In direct mode all graphics actions are directly shown at the screen, without the use of MOL-items or MOL-objects. (Toggle all MOL-objects off if nothing happens).

Protons will always get a colour that differs a very little bit from the colour of the heavy atom they are connected to.

Colour by atomic properties

Colouring by atom type (COLATM)

This is the default colouring scheme. The command COLATM causes WHAT IF to prompt you for the residue range. The residues you give will get the following atomic colouring scheme: all nitrogens become blue, oxygens become red, carbons become green, and sulphers become dirty yellow. Residues outside the requested range keep the old colouring scheme.

Colour by average B-factor (COLABF)

The command COLABF does the same as the command COLBFT, with as only difference that The average atomic B-factor is calculated first, and this value is used for all atoms in the residue. The atomic B-factors that are attached to the atoms will not be averaged, so the soup remains unchanged, only the avaerage value will be used. All averaged B-factors are then divided into 12 bins, and coloured in 12 steps from cold to hot, blue to red. The divisions are made such that the colour-value is a linear function of the B-factor. WHAT IF will prompt you for the residue range. Only the residues you give will be used in the calculation of bins etc. and get their colours changed. You can change the range between which the colours are ranged with the COLRNG command, be aware however that WHAT IF always makes bins that are ten HUE-value steps wide, so if you colour for example from yellow (HUE=180) to green (HUE=240) you will only get 6 colours.

Colouring by accessibility (COLACC)

The command COLACC causes WHAT IF to prompt you for the residue range. The residues you give will get coloured atom by atom blue till red as function of their accessibility. See also COLRNG and COLBIN.

Colour by B-factor (COLBFT)

The command COLBFT changes the atom colours such that the coldest atom (that is the one with the lowest crystallographic B-factor) becomes blue, and the hottest (highest B-factor) becomes red. All B-factors are then divided into 12 bins, and coloured in 12 steps from cold to hot, blue to red. The divisions are made such that the colour-value is a linear function of the B-factor. WHAT IF will prompt you for the residue range. Only the residues you give will be used in the calculation of bins etc. and get their colours changed. You can change the range between which the colours are ranged with the COLRNG command, be aware however that WHAT IF always makes bins that are ten HUE-value steps wide, so if you colour for example from yellow (HUE=180) to green (HUE=240) you will only get 6 colours.

Colour by charge (COLCHG)

The command COLCHG changes the default atom colours such that the most negative atom becomes blue, and the most positive one becomes red. All charges are divided into 12 bins, and coloured in 12 steps from negative to positive, blue to red. The divisions are made such that the colour-value is a linear function of the charge. WHAT IF will prompt you for the residue range. Only the residues you give will be used in the calculation of bins etc. and get their colours changed.

Colour by energy content (COLETM)

After you have analyzed a GROMOS output (see the GETETM command in the chapter on GROMOS) you get a table of individual atomic energy values. GETETM (See the chapter on energy calculations and GROMOS) causes WHAT IF to prompt you for the name of the file with these energy values. If you ran the analysis from within WHAT IF, then it uses the file created in that process as the default. WHAT IF will then read this file. COLETM uses the same colouring algorithm as COLBFT does. The only difference is that COLBFT uses the B-factor range from cold to hot to go from blue to red; COLETM uses the energy range from low to high to colour from blue to red. You can change the range between which the colours are ranged with the COLRNG command, be aware however that WHAT IF always makes bins that are ten HUE-value steps wide, so if you colour for example from yellow (HUE=180) to green (HUE=240) you will only get 6 colours.

Colouring water (COLHSP)

The command COLHSP will cause WHAT IF to prompt you for the name of an HSSP file (see the chapter on HSSP). You will also be prompted for the number of the molecule in the soup that should correspond with the HSSP file. In principle the HSSP file should be based on this molecule in the soup. However, to allow you to fool WHAT IF, you will be asked if the molecule in the soup and the HSSP file should match exactly. If you say YES, error messages are issued upon detection of differences in the sequence in the soup and the HSSP file. If you say NO, different sequences in the soup and the HSSP file are allowed. This is nice if you want to use the HSSP file of a wild type molecule to colour a mutated molecule. There is no way to predict what will happen if the HSSP file and the molecule in the soup in no way belong together.

Colour by secundary structure (COLHST)

COLHST (=Colour Helix, Sheet and Turn) will colour the residues according to their secondary structure as determined by DSSP. (If the secondary structure has not been determined yet, then this will be done first automatically by WHAT IF). the following colour scheme is used:
H (helix)      : 30   BLUE-ISH PURPLE
3 (3-10 helix) : 50   PURPLE
S (sheet)      : 130  RED
T (turn)       : 290  BLUE-ISH GREEN
C (coil)       : 260  GREEN
  (coil)       : 260  GREEN

Colour symmetry contacting residues (COLSMC)

The command COLSMC will prompt you for a residue range and a colour. All residues in this range that make a crystal contact in the crystal will get the indicated colour. You will also be prompted for an environment. Here you should give the molecules that belong together in one dataset or PDB file.

This option is rather useless for models and structures solved by NMR.

Colour as function of geometric error (COLREF)

The command COLREF will prompt you for residue range(s). For all residues in this range the Z score for geometric errors will be calculated. Atoms with perfect geometry (only bond lengths and bond angles with covalently connected neighbour atoms are evaluated) get coloured green (for perfect) to red (for 10 sigma or more deviating from perfect).

Colour by residue type (COLTYP)

COLTYP allows you to set all atoms of all residues, of one or more types to the same colour. You will first be prompted for the residue range and for the residue types. Then you will be prompted for the colour. The colour should be a HUE-value between 1 and 360. If you do not know what HUE-values are, just hit return, and some info will pop up. All requested residues within the given range will get the given colour.

Colouring parts of soup with one colour

Colour zones of residues (COLZNS)

COLZNS allows you to set all atoms of multiple zones of residues to the same colour. You will be prompted for that colour and for the residue ranges. All atoms in all residues within the given ranges will get the given overall colour.

Colouring the backbone only (COLBB)

The command COLBB will cause WHAT IF to prompt you for a residue range and for a colour. All backbone atoms (N, C-alpha, C and O) of this range will get the requested colour. This option only works on proteins.

Colouring molecules (COLMOL)

The command COLMOL will cause WHAT IF to prompt you for a colour and for a molecule number. This whole molecule will get the requested colour. This option can be used for all types of molecules (protein, nucleic acid, drug, group of waters).

Colouring clusters (COLCLU)

COLCLU will prompt you for a cluster and a colour. All atoms in all residues in that cluster will get the requested colour.You need to run the SETCLU option in the CLUFAM menu before you can use this option.

Colouring families (COLFAM)

COLFAM will prompt you for a family and a colour. All atoms in all residues in that family will get the requested colour. You need to run the SETFAM option in the CLUFAM menu before you can use this option.

Colouring water (COLH2O)

The command COLH2O will cause WHAT IF to prompt you for a colour. It will then colour all waters in the soup accordingly (if there are any of course).

Colouring the side chains only (COLSCH)

The command COLSCH will cause WHAT IF to prompt you for a residue range and for a colour. All side chain atoms of this range will get the requested colour. This option only works on proteins.

Other colouring related options

Special colouring modes (COLSPC)

The command COLSPC will show several special pre-defined colouring schemes. You can just loop through them and say YES when you see a scheme that you like. I suggest you just take a look what is in there.

Scale colours in bins (COLBIN)

The command COLBIN will prompt you for a residue range. All colours will be scaled such that all colours occurr roughly equally often. For example, if you have your molecule coloured as function of the B-factor from blue till red, and one residue has a B-factor much higher than all others, then you will see a virtually completely blue molecule with one red residue. COLBIN will cause the 8% atoms with the highest B-factor to all get the same colour (red in this example); the next 8% atoms with highest B-factors will get a little bit blueish red, etc. The 8% residues with the lowes B-factors will get dark blue. If you choose another colour range you can get another percentage of atoms per colour bin. Just experiment a bit.

Colour by residue property (COLPRP)

Several options in WHAT IF add values to residues (e.g. hydrophobic moment calculation, HSSP mutability, etc.). The property value of each residue is shown as (Prp=value) on the top line of the LISTA output of each residue.

COLPRP colours all residues according to their property value. The property value per residue is used for all atoms in the residue.

All property values are divided into 12 bins, and coloured in 12 steps from low to high, blue to red. The divisions are made such that the colour-value is a linear function of the property value. WHAT IF will prompt you for the residue range. Only the residues you give will be used in the calculation of bins etc. and get their colours changed. You can change the range between which the colours are ranged with the COLRNG command, be aware however that WHAT IF only uses bins that are ten HUE-value steps wide, so if you colour for example from yellow (HUE=180) to green (HUE=240) you will only get 6 colours.

Setting the colour range (COLRNG)

Several colouring options map a physical parameter range on a colour range. Eg. COLBFT colours from blue till red as function of the B-factor. If you want to change the colour extremes of those ranges, you can use the COLRNG option. WHAT IF will prompt you for the two extremes. You are not allowed to give twice the same colour. Everything else is possible, also inverting the ranges (go from red till blue rather then from blue till red). WHAT IF will not always do what you expected if you use 360 as one of the extreme colours.

Shifting colour ranges (COLSHF)

The command COLSHF is a dirty hack that allows you to shift all colours in a certain range. You are prompted for the lower and higher colour extreme of a colour range. All atomic colours within this range are shifted upwards so that no atoms are left with a colour within this range. So if the range is 40 wide, all colours within this range will become 40 bigger.

Changing colours (COLREP)

The command COLREP will cause WHAT IF to prompt you for an old and a new colour. All atoms that have the old colour will get the new colour. This is in the soup, and only in DIRECT mode also in the graphics window. This option only operates on heavy atoms. If you have protons in the soup, their colour will be updated automatically.

Colour by parameter correlation row (COLROW)

COLROW colours according to the true false values in an atomic corelation row. See the SEARCH menu description for the generation of these rows. Every atom for which the atomic parameter row value is true will become green. If the value is false, the atom becomes red. You need to create a row before you can use this option of course.

Colour as function of table values (COLTAB)

The command COLTAB colours the atoms as function of the values in a table. You will be prompted for the table number and for the residue range. The residues in this range will be coloured as function of the corresponding table value. The residue with the lowest becomes blue, and the the one with the highest table value becomes red.

You can change the range between which the colours are ranged with the COLRNG command, be aware however that WHAT IF always makes bins that are ten HUE-value steps wide, so if you colour for example from yellow (HUE=180) to green (HUE=240) you will only get 6 colours.

You need to create at least one table before you can use this option of course.

Hidden options (HIDDEN)

Several hidden options can be found in the colour menu. These are often quick fixes written on request. It therefore seems unlikely that these options will be fully documented. There is also no guarantee that they will all work. Just try them out. Perhaps you will find something useful among them. Type HIDDEN to get a list of the hidden options.