# -*- Mode: python; tab-width: 4; indent-tabs-mode:nil; -*-
# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4
#
# MDAnalysis --- http://mdanalysis.googlecode.com
# Copyright (c) 2006-2011 Naveen Michaud-Agrawal,
# Elizabeth J. Denning, Oliver Beckstein,
# and contributors (see website for details)
# Released under the GNU Public Licence, v2 or any higher version
#
# Please cite your use of MDAnalysis in published work:
#
# N. Michaud-Agrawal, E. J. Denning, T. B. Woolf, and
# O. Beckstein. MDAnalysis: A Toolkit for the Analysis of
# Molecular Dynamics Simulations. J. Comput. Chem. 32 (2011), 2319--2327,
# doi:10.1002/jcc.21787
#
# pdb.extensions
# original file: edPDB.xpdb but only kept content needed for MDAnalysis
"""
:mod:`pdb.extensions` -- Extensions to :mod:`Bio.PDB`
=====================================================
:Author: Oliver Beckstein
:Year: 2009
:License: Biopython
Extension to :mod:`Bio.PDB` to handle large pdb files.
Partly published on http://biopython.org/wiki/Reading_large_PDB_files
and more code at
http://github.com/orbeckst/GromacsWrapper/tree/master/edPDB/
Module content
--------------
.. autoclass:: SloppyStructureBuilder
.. autoclass:: SloppyPDBIO
.. autofunction:: get_structure
.. autofunction:: write_pdb
"""
import Bio.PDB
import Bio.PDB.StructureBuilder
import logging
logger = logging.getLogger('MDAnalysis.pdb.extensions')
[docs]class SloppyStructureBuilder(Bio.PDB.StructureBuilder.StructureBuilder):
"""Cope with resSeq < 10,000 limitation by just incrementing internally.
Solves the follwing problem with :class:`Bio.PDB.StructureBuilder.StructureBuilder`:
Q: What's wrong here??
Some atoms or residues will be missing in the data structure.
WARNING: Residue (' ', 8954, ' ') redefined at line 74803.
PDBConstructionException: Blank altlocs in duplicate residue SOL (' ', 8954, ' ') at line 74803.
A: resSeq only goes to 9999 --> goes back to 0 (PDB format is not really good here)
.. warning:: H and W records are probably not handled yet (don't have examples to test)
"""
def __init__(self,verbose=False):
Bio.PDB.StructureBuilder.StructureBuilder.__init__(self)
self.max_resseq = -1
self.verbose = verbose
def init_residue(self, resname, field, resseq, icode):
"""
Initiate a new Residue object.
Arguments:
o resname - string, e.g. "ASN"
o field - hetero flag, "W" for waters, "H" for
hetero residues, otherwise blanc.
o resseq - int, sequence identifier
o icode - string, insertion code
"""
if field!=" ":
if field=="H":
# The hetero field consists of H_ + the residue name (e.g. H_FUC)
field="H_"+resname
res_id=(field, resseq, icode)
if resseq > self.max_resseq:
self.max_resseq = resseq
if field==" ":
fudged_resseq = False
while (self.chain.has_id(res_id) or resseq == 0):
# There already is a residue with the id (field, resseq, icode).
# resseq == 0 catches already wrapped residue numbers which do not
# trigger the has_id() test.
#
# Be sloppy and just increment...
# (This code will not leave gaps in resids... I think)
#
# XXX: shouldn't we also do this for hetero atoms and water??
self.max_resseq += 1
resseq = self.max_resseq
res_id = (field, resseq, icode) # use max_resseq!
fudged_resseq = True
if fudged_resseq and self.verbose:
logger.debug("Residues are wrapping (Residue ('%s', %i, '%s') at line %i)."
% (field, resseq, icode, self.line_counter) +
".... assigning new resid %d.\n" % self.max_resseq)
residue=Bio.PDB.Residue.Residue(res_id, resname, self.segid)
self.chain.add(residue)
self.residue=residue
[docs]class SloppyPDBIO(Bio.PDB.PDBIO):
"""PDBIO class that can deal with large pdb files as used in MD simulations.
- resSeq simply wrap and are printed modulo 10,000.
- atom numbers wrap at 99,999 and are printed modulo 100,000
"""
# directly copied from PDBIO.py
# (has to be copied because of the package layout it is not externally accessible)
_ATOM_FORMAT_STRING="%s%5i %-4s%c%3s %c%4i%c %8.3f%8.3f%8.3f%6.2f%6.2f %4s%2s%2s\n"
def _get_atom_line(self, atom, hetfield, segid, atom_number, resname,
resseq, icode, chain_id, element=" ", charge=" "):
"""
Returns an ATOM PDB string that is guaranteed to fit into the ATOM format.
- Resid (resseq) is wrapped (modulo 10,000) to fit into %4i (4I) format
- Atom number (atom_number) is wrapped (modulo 100,000) to fit into %4i (4I) format
"""
if hetfield!=" ":
record_type="HETATM"
else:
record_type="ATOM "
name=atom.get_fullname()
altloc=atom.get_altloc()
x, y, z=atom.get_coord()
bfactor=atom.get_bfactor()
occupancy=atom.get_occupancy()
args=(record_type, atom_number % 100000, name, altloc, resname, chain_id,
resseq % 10000, icode, x, y, z, occupancy, bfactor, segid,
element, charge)
return self._ATOM_FORMAT_STRING % args
sloppyparser = Bio.PDB.PDBParser(PERMISSIVE=True,structure_builder=SloppyStructureBuilder())
[docs]def get_structure(pdbfile,pdbid='system'):
"""Read the *pdbfilename* and return a Bio.PDB structure.
This function ignores duplicate atom numbers and resids from the
file and simply increments them.
.. Note::
The call signature is reversed compared to the one of
:meth:`Bio.PDB.PDBParser.get_structure`.
"""
return sloppyparser.get_structure(pdbid,pdbfile)
[docs]def write_pdb(structure, filename, **kwargs):
"""Write Bio.PDB molecule *structure* to *filename*.
:Arguments:
*structure*
Bio.PDB structure instance
*filename*
pdb file
*selection*
Bio.PDB.Selection
"""
selection = kwargs.pop('selection', None)
io = SloppyPDBIO() # deals with resSeq > 9999
io.set_structure(structure)
io.save(filename, select=selection)