The Chain class: a single chain in a model or alignment

The Chain class holds information about a single chain, in a model (see Sequence.chains), an alignment sequence, or an alignment template structure.

Two Chain objects are considered equal if and only if they represent the same chain in the same sequence.

Example: examples/python/chains.py

# Example for 'chain' objects

from modeller import *
from modeller.scripts import complete_pdb

env = environ()
env.io.atom_files_directory = ['../atom_files']
env.libs.topology.read(file='$(LIB)/top_heav.lib')
env.libs.parameters.read(file='$(LIB)/par.lib')

mdl = complete_pdb(env, "1b3q")

# Print existing chain IDs and lengths:
print("Chain IDs and lengths: " \
      + str([(c.name, len(c.residues)) for c in mdl.chains]))

# Set new chain IDs:
mdl.chains['A'].name = 'X'
mdl.chains['B'].name = 'Y'

# Write out chain sequences:
for c in mdl.chains:
    c.write(file='1b3q%s.chn' % c.name, atom_file='1b3q',
            align_code='1b3q%s' % c.name)