Interhlx may be what you are looking for
http://nmr.uhnres.utoronto.ca/ikura/resources/data+sw/interhlx/ > Dear all, > I want to compare the conformational change of two similar structures, > using one alpha helix as the reference. Then, how can I get a vector that > can represent both the position and direction of the helix? Is there any > well-known software can do this? > Or, should I build a cylinder model, with parameters [radius,bottom > center(x1,y1,z1),top center(x1,y2,z2)], using the coordinates of > C,C(alpha) > and N to fit these parameters? > Thanks for any suggestions > > Regards, > Yuan SHANG > -- Edwin Pozharski, PhD University of Maryland, Baltimore