[BioPython] Bio.PDB phi/psi angles

[Douglas Kojetin]

Hi All,

I would like to print the phi/psi angles for a structure using the  
script found here:

http://www2.warwick.ac.uk/fac/sci/moac/currentstudents/peter_cock/ 
python/ramachandran/calculate/

but the script chokes on the following line:

phi_psi = poly.get_phi_psi_list()

error output:

Traceback (most recent call last):
   File "./ramachandran_biopython.py", line 62, in <module>
     phi_psi = poly.get_phi_psi_list()
   File "/sw/lib/python2.5/site-packages/Bio/PDB/Polypeptide.py",  
line 169, in get_phi_psi_list
     res.xtra["PHI"]=phi
NameError: global name 'res' is not defined


Does anyone know what I can do to overcome this problem?

Thanks,

Doug