The first thing which needs to be completed prior to any spin specific command is to generate the molecule, residue and spin data structures for storing the spin specific data. In the sample script above, this is generated from a plain text file with the sequence information, however a PDB file can be used instead (see the structure.read_pdb user function on page for more details). In the case of the sample script, the command:
[firstnumber=45] # Load the sequence. sequence.read('fake_sequence.in', res_num_col=1, res_name_col=2)
will load residue names and numbers from the fake_sequence.in file into relax, creating one spin per residue. Then:
[firstnumber=48] # Name the spins so they can be matched to the assignments, and the isotope for field strength scaling. spin.name(name='N') spin.isotope(isotope='15N')
will set up the spin information required for loading the peak intensity data from Sparky peak lists and for the analysis of the dispersion data.