Dear Chimera users, I am trying to write a script to change the phi and psi angle of a peptide. I am trying to adapt the code from http://plato.cgl.ucsf.edu/pipermail/chimera-users/2005-September/000456.html . I am trying to invert the angles so I am multiplying the angles by -1. My code is import chimera from chimera import selection, UserError, BondRot, replyobj opened = chimera.openModels.open('fun.pdb') mol = opened[0] RES_LIST = mol.residues for res in mol.residues: b = str(res.phi) if b != 'None': c = -1*float(b) atomsMap = res.atomsMap N = atomsMap['N'][0] CA = atomsMap['CA'][0] C = atomsMap['C'][0] CAmap = CA.bondsMap phiBond = CAmap[N] psiBond = CAmap[C] phiAnchor = N psiAnchor = CA phi = BondRot(phiBond) phi.setAngle(c, phiAnchor) When I run this script i get the error phi.setAngle(c, phiAnchor) AttributeError: '_molecule.BondRot' object has no attribute 'setAngle' Can someone please help me with this? Warm regards. Amin.