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$ ruff --fix --select PIE790 BioSQL/ Bio/ Doc/examples/ Tests/ Scripts/ Found 62 errors (62 fixed, 0 remaining). Then re-ran black.
412 lines
13 KiB
Python
412 lines
13 KiB
Python
# Copyright (C) 2002, Thomas Hamelryck (thamelry@binf.ku.dk)
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# This code is part of the Biopython distribution and governed by its
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# license. Please see the LICENSE file that should have been included
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# as part of this package.
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"""Output of PDB files."""
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import warnings
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# Exceptions and Warnings
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from Bio import BiopythonWarning
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from Bio.PDB.PDBExceptions import PDBIOException
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# To allow saving of chains, residues, etc..
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from Bio.PDB.StructureBuilder import StructureBuilder
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# Allowed Elements
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from Bio.Data.IUPACData import atom_weights
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_ATOM_FORMAT_STRING = (
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"%s%5i %-4s%c%3s %c%4i%c %8.3f%8.3f%8.3f%s%6.2f %4s%2s%2s\n"
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)
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_PQR_ATOM_FORMAT_STRING = (
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"%s%5i %-4s%c%3s %c%4i%c %8.3f%8.3f%8.3f %7s %6s %2s\n"
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)
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_TER_FORMAT_STRING = (
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"TER %5i %3s %c%4i%c \n"
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)
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class Select:
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"""Select everything for PDB output (for use as a base class).
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Default selection (everything) during writing - can be used as base class
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to implement selective output. This selects which entities will be written out.
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"""
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def __repr__(self):
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"""Represent the output as a string for debugging."""
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return "<Select all>"
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def accept_model(self, model):
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"""Overload this to reject models for output."""
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return 1
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def accept_chain(self, chain):
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"""Overload this to reject chains for output."""
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return 1
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def accept_residue(self, residue):
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"""Overload this to reject residues for output."""
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return 1
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def accept_atom(self, atom):
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"""Overload this to reject atoms for output."""
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return 1
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_select = Select()
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class StructureIO:
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"""Base class to derive structure file format writers from."""
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def __init__(self):
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"""Initialise."""
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def set_structure(self, pdb_object):
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"""Check what the user is providing and build a structure."""
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# The idea here is to build missing upstream components of
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# the SMCRA object representation. E.g., if the user provides
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# a Residue, build Structure/Model/Chain.
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if pdb_object.level == "S":
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structure = pdb_object
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else: # Not a Structure
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sb = StructureBuilder()
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sb.init_structure("pdb")
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sb.init_seg(" ")
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if pdb_object.level == "M":
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sb.structure.add(pdb_object.copy())
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self.structure = sb.structure
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else: # Not a Model
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sb.init_model(0)
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if pdb_object.level == "C":
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sb.structure[0].add(pdb_object.copy())
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else: # Not a Chain
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chain_id = "A" # default
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sb.init_chain(chain_id)
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if pdb_object.level == "R": # Residue
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# Residue extracted from a larger structure?
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if pdb_object.parent is not None:
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og_chain_id = pdb_object.parent.id
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sb.structure[0][chain_id].id = og_chain_id
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chain_id = og_chain_id
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sb.structure[0][chain_id].add(pdb_object.copy())
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else: # Atom
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sb.init_residue("DUM", " ", 1, " ") # Dummy residue
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sb.structure[0][chain_id].child_list[0].add(pdb_object.copy())
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# Fix chain identifier if Atom has grandparents.
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try:
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og_chain_id = pdb_object.parent.parent.id
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except AttributeError: # pdb_object.parent == None
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pass
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else:
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sb.structure[0][chain_id].id = og_chain_id
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# Return structure
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structure = sb.structure
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self.structure = structure
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class PDBIO(StructureIO):
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"""Write a Structure object (or a subset of a Structure object) as a PDB or PQR file.
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Examples
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--------
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>>> from Bio.PDB import PDBParser
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>>> from Bio.PDB.PDBIO import PDBIO
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>>> parser = PDBParser()
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>>> structure = parser.get_structure("1a8o", "PDB/1A8O.pdb")
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>>> io=PDBIO()
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>>> io.set_structure(structure)
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>>> io.save("bio-pdb-pdbio-out.pdb")
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>>> import os
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>>> os.remove("bio-pdb-pdbio-out.pdb") # tidy up
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"""
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def __init__(self, use_model_flag=0, is_pqr=False):
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"""Create the PDBIO object.
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:param use_model_flag: if 1, force use of the MODEL record in output.
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:type use_model_flag: int
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:param is_pqr: if True, build PQR file. Otherwise build PDB file.
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:type is_pqr: Boolean
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"""
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self.use_model_flag = use_model_flag
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self.is_pqr = is_pqr
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# private methods
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def _get_atom_line(
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self,
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atom,
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hetfield,
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segid,
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atom_number,
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resname,
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resseq,
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icode,
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chain_id,
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charge=" ",
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):
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"""Return an ATOM PDB string (PRIVATE)."""
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if hetfield != " ":
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record_type = "HETATM"
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else:
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record_type = "ATOM "
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# Atom properties
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# Check if the atom serial number is an integer
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# Not always the case for structures built from
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# mmCIF files.
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try:
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atom_number = int(atom_number)
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except ValueError:
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raise ValueError(
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f"{atom_number!r} is not a number."
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"Atom serial numbers must be numerical"
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" If you are converting from an mmCIF"
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" structure, try using"
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" preserve_atom_numbering=False"
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)
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if atom_number > 99999:
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raise ValueError(
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f"Atom serial number ('{atom_number}') exceeds PDB format limit."
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)
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# Check if the element is valid, unknown (X), or blank
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if atom.element:
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element = atom.element.strip().upper()
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if element.capitalize() not in atom_weights and element != "X":
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raise ValueError(f"Unrecognised element {atom.element}")
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element = element.rjust(2)
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else:
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element = " "
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# Format atom name
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# Pad if:
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# - smaller than 4 characters
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# AND - is not C, N, O, S, H, F, P, ..., one letter elements
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# AND - first character is NOT numeric (funky hydrogen naming rules)
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name = atom.fullname.strip()
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if len(name) < 4 and name[:1].isalpha() and len(element.strip()) < 2:
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name = " " + name
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altloc = atom.altloc
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x, y, z = atom.coord
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# Write PDB format line
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if not self.is_pqr:
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bfactor = atom.bfactor
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try:
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occupancy = f"{atom.occupancy:6.2f}"
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except (TypeError, ValueError):
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if atom.occupancy is None:
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occupancy = " " * 6
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warnings.warn(
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f"Missing occupancy in atom {atom.full_id!r} written as blank",
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BiopythonWarning,
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)
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else:
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raise ValueError(
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f"Invalid occupancy value: {atom.occupancy!r}"
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) from None
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args = (
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record_type,
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atom_number,
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name,
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altloc,
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resname,
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chain_id,
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resseq,
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icode,
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x,
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y,
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z,
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occupancy,
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bfactor,
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segid,
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element,
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charge,
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)
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return _ATOM_FORMAT_STRING % args
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# Write PQR format line
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else:
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try:
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pqr_charge = f"{atom.pqr_charge:7.4f}"
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except (TypeError, ValueError):
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if atom.pqr_charge is None:
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pqr_charge = " " * 7
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warnings.warn(
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f"Missing PQR charge in atom {atom.full_id} written as blank",
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BiopythonWarning,
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)
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else:
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raise ValueError(
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f"Invalid PQR charge value: {atom.pqr_charge!r}"
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) from None
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try:
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radius = f"{atom.radius:6.4f}"
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except (TypeError, ValueError):
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if atom.radius is None:
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radius = " " * 6
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warnings.warn(
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f"Missing radius in atom {atom.full_id} written as blank",
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BiopythonWarning,
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)
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else:
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raise ValueError(f"Invalid radius value: {atom.radius}") from None
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args = (
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record_type,
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atom_number,
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name,
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altloc,
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resname,
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chain_id,
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resseq,
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icode,
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x,
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y,
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z,
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pqr_charge,
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radius,
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element,
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)
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return _PQR_ATOM_FORMAT_STRING % args
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# Public methods
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def save(self, file, select=_select, write_end=True, preserve_atom_numbering=False):
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"""Save structure to a file.
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:param file: output file
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:type file: string or filehandle
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:param select: selects which entities will be written.
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:type select: object
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Typically select is a subclass of L{Select}, it should
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have the following methods:
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- accept_model(model)
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- accept_chain(chain)
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- accept_residue(residue)
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- accept_atom(atom)
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These methods should return 1 if the entity is to be
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written out, 0 otherwise.
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Typically select is a subclass of L{Select}.
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"""
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if isinstance(file, str):
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fhandle = open(file, "w")
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else:
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# filehandle, I hope :-)
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fhandle = file
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get_atom_line = self._get_atom_line
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# multiple models?
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if len(self.structure) > 1 or self.use_model_flag:
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model_flag = 1
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else:
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model_flag = 0
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for model in self.structure.get_list():
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if not select.accept_model(model):
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continue
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# necessary for ENDMDL
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# do not write ENDMDL if no residues were written
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# for this model
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model_residues_written = 0
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if not preserve_atom_numbering:
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atom_number = 1
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if model_flag:
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fhandle.write(f"MODEL {model.serial_num}\n")
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for chain in model.get_list():
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if not select.accept_chain(chain):
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continue
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chain_id = chain.id
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if len(chain_id) > 1:
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e = f"Chain id ('{chain_id}') exceeds PDB format limit."
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raise PDBIOException(e)
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# necessary for TER
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# do not write TER if no residues were written
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# for this chain
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chain_residues_written = 0
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for residue in chain.get_unpacked_list():
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if not select.accept_residue(residue):
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continue
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hetfield, resseq, icode = residue.id
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resname = residue.resname
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segid = residue.segid
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resid = residue.id[1]
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if resid > 9999:
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e = f"Residue number ('{resid}') exceeds PDB format limit."
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raise PDBIOException(e)
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for atom in residue.get_unpacked_list():
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if not select.accept_atom(atom):
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continue
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chain_residues_written = 1
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model_residues_written = 1
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if preserve_atom_numbering:
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atom_number = atom.serial_number
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try:
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s = get_atom_line(
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atom,
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hetfield,
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segid,
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atom_number,
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resname,
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resseq,
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icode,
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chain_id,
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)
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except Exception as err:
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# catch and re-raise with more information
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raise PDBIOException(
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f"Error when writing atom {atom.full_id}"
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) from err
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else:
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fhandle.write(s)
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# inconsequential if preserve_atom_numbering is True
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atom_number += 1
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if chain_residues_written:
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fhandle.write(
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_TER_FORMAT_STRING
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% (atom_number, resname, chain_id, resseq, icode)
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)
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if model_flag and model_residues_written:
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fhandle.write("ENDMDL\n")
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if write_end:
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fhandle.write("END \n")
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if isinstance(file, str):
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fhandle.close()
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