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# Copyright (C) 2002, Thomas Hamelryck (thamelry@vub.ac.be)
# This code is part of the Biopython distribution and governed by its
# license. Please see the LICENSE file that should have been included
# as part of this package.
import sys
# Redirect stderr so user does not see warnings
class TheVoid:
# Class to hide stderr output
def write(self, string):
pass
def run_test():
from Bio.PDB import PDBParser, PPBuilder, CaPPBuilder
# first make a PDB parser object
p=PDBParser(PERMISSIVE=1)
# get the structure, call it "example"
structure=p.get_structure("example", "PDB/a_structure.pdb")
# now loop over content and print some info
for model in structure.get_list():
model_id=model.get_id()
print "Model %i contains %i chains." % (model_id, len(model))
for chain in model.get_list():
chain_id=chain.get_id()
print "\tChain '%s' contains %i residues." % (chain_id, len(chain))
for residue in chain.get_list():
residue_id=residue.get_id()
hetfield, resseq, icode=residue_id
print "\t\tResidue ('%s', %i, '%s') contains %i atoms." % (hetfield, resseq, icode, len(residue))
# check if there is disorder due to a point mutation --- this is rare
if residue.is_disordered()==2:
print "\t\t\tThere is a point mutation present in the crystal at this position."
s="\t\t\tResidues at this position are "
for resname in residue.disordered_get_id_list():
s=s+resname+" "
print s[:-1]+"."
# count the number of disordered atoms
if residue.is_disordered()==1:
disordered_count=0
for atom in residue.get_list():
if atom.is_disordered():
disordered_count=disordered_count+1
if disordered_count>0:
print "\t\t\tThe residue contains %i disordered atoms." % disordered_count
print "Polypeptides using C-N"
ppb=PPBuilder()
for pp in ppb.build_peptides(structure[1]):
print pp
print "Polypeptides using CA-CA"
ppb=CaPPBuilder()
for pp in ppb.build_peptides(structure[1]):
print pp
old_stderr = sys.stderr
# Hide stderr output for user
sys.stderr=TheVoid()
try:
run_test()
finally:
sys.stderr = old_stderr
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