Jie Liu wrote: > Dear CCP4ers: > > Does anyone know an existing program to calculate the lateral > displacement---the vertical offset, measured as a fraction of the > the heptad repeat---of neighboring helices in coiled coils or helix > bundles, either parallel or antiparallel? > > Your input is greatly appreciated. > > Have a nice weekend! > > Jie > > >
Maybe I dont understand the question.. If you know what you want to match to what cant you just superpose the Cas of helix i onto those of helix j and sort it out from that? Selecting the match might be tricky but you must have done that? You will need to do some geometric fiddling I guess. The Superpose molecule option from the GUI would give you the centre of mass of each segment and the direction cosines for the transformation, which will be those for the helix axes. I think the dot product of the COM onto the DCs would give you the relative displacements in As (X_com1*DC1 + Y_com1*DC2 + Z_com1*DC3) - (X_com2*DC1 + Y_com2*DC2 + Z_com2*DC3) Eleanor
