bezier curve for protein ruban

Thats dones! I am quite happy to finally get a nice protein worm representation directly in blender. But there is still the coloring method problem...I have to associate vertex with material according physical property...And try to display arrow and helix for secondary structure type...
(thanks to the blender tutorial here :http://jmsoler.free.fr/didacticiel/blender/tutor/cpl_celticknot.htm and the API help)