This script allows you to calculate the elbow angle of an antibody Fab fragment object and optionally draw a graphical representation of the vectors used to calculate the elbow angle.
elbow_angle object [, light=L [, heavy=H [, limit_l=107 [, limit_h=113 [, draw=0 ]]]]]
The first argument should be a PyMOL object. You can calculate the elbow angles of multiple Fabs from the same object (one at a time) by specifying the chains manually for each Fab.
The `light` and `heavy` arguments are for PDB chain IDs, and `limit_l` and `limit_h` are the last residue of the light and heavy chain variable domains, respectively. (For Kabat-numbered structures, these limits will be 107 and 113, respectively. For structures with different numbering schemes, the limits can be estimated by visual inspection of the PDB file.) ..→