pepwheel
    Function
    Description
pepwheel displays peptide sequences in a helical representation.
This gives a view of a helix from a protein sequence looking down the
axis of the helix. 
It is useful for highlighting amphipathicity and other properties of
residues around a helix. 
    Usage
    Command line arguments
    Input file format
pepwheel reads any protein sequence USA.
    Output file format
An image is output to the specified graphics device.
    Data files
None.
    Notes
The default settings for turn (5) and steps (18) apply to alpha
helices. For other possible secondary structures, see the following
table:
helix       phi   psi  omega  res/turn  transl.  turns  steps
alpha       -57   -47    180       3.6     1.50      5     18
3-10        -49   -26    180       3.0     2.00      1      3
pi          -57   -70    180       4.4     1.15      5     22
PP I        -83   158      0       3.33    1.9       3     10
PP II       -78   149    180       3.0     3.12      1      3
PG II       -80   150    180       3.0     3.1       1      3
anti Beta  -139   135   -178       2.0     3.4       4      9
para Beta  -119   113    180       2.0     3.2       4      9
PP is polyproline
PG II is polyGlycine.
    References
- 
Rachamandran and Sasisekharan, Adv. Protein Chem.
23:283-437, 1968
- 
IUPAC-IUB Commission on biochemical nomenclature,
Biochemistry 9:3471-3479, 1970
    Warnings
When you specify the number of turns and steps, be aware that you
should remove common factors from these two numbers.  For example, if
you (for some improbable reason) wished to plot a wheel with 8 turns
in 18 steps (2.25 residues per turn) you should remove the common
factor (i.e.  2) and specify 4 turns in 9 steps.
    Diagnostic Error Messages
None.
    Exit status
0 upon successful completion.
    Known bugs
None.
    Author(s)
    History
    Target users
    Comments