Drawing Transmembrane regions

[books at mcvax2.d48.lilly.com]

Published articles have tramsmemebranes peptide sequences drawn to illuastrate
the transmembrane regions in the lipid bilayer. The amino acids are enclosed in 
circle and the circles are connect like beads on a string. Is there computer 
program availible to do this type of drawing? How do people create this type 
of figure? I am doing this by hand and it is not easy! Thanks DPSMITH 
                                      internet:smith_dennis_p at lilly.com