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arpeggio.py
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arpeggio.py
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#!/usr/bin/python
##################################################################################################################################
# #
# CREDO-BASED DEFINITIONS: #
# #
# https://bitbucket.org/harryjubb/credovi/src/ac69222542134bb86d26a24561e4f740466e2b0e/credovi/config/credo.json?at=default #
# https://bitbucket.org/harryjubb/credovi/src/ac69222542134bb86d26a24561e4f740466e2b0e/credovi/structbio/structure.py?at=default #
# #
##################################################################################################################################
###########
# IMPORTS #
###########
import argparse
import collections
import logging
import functools
#import math
import operator
try:
import resource
except ImportError:
logging.info('Resource module not available, resource usage info won\'t be logged.')
import sys
import warnings
warnings.filterwarnings("ignore")
from collections import OrderedDict
import numpy as np
#from Bio.PDB import PDBIO
from Bio.PDB.PDBParser import PDBParser
from Bio.PDB import NeighborSearch
from Bio.PDB.Atom import Atom
from Bio.PDB.Residue import Residue
from Bio.PDB.Polypeptide import PPBuilder
import openbabel as ob
#############
# CONSTANTS #
#############
from config import ATOM_TYPES, CONTACT_TYPES, VDW_RADII, METALS, \
HALOGENS, CONTACT_TYPES_DIST_MAX, FEATURE_SIFT, VALENCE, \
MAINCHAIN_ATOMS, THETA_REQUIRED, STD_RES, PROT_ATOM_TYPES, \
AMIDE_SMARTS, COMMON_SOLVENTS, STANDARD_NUCLEOTIDES
###########
# CLASSES #
###########
class HydrogenError(Exception):
def __init__(self):
logging.error('Please remove all hydrogens from the structure then re-run.')
class OBBioMatchError(Exception):
def __init__(self, serial=''):
if not serial:
logging.error('An OpenBabel atom could not be matched to a BioPython counterpart.')
else:
logging.error('OpenBabel OBAtom with PDB serial number {} could not be matched to a BioPython counterpart.'.format(serial))
class AtomSerialError(Exception):
def __init__(self):
logging.error('One or more atom serial numbers are duplicated.')
class SiftMatchError(Exception):
def __init__(self):
logging.error('Seeing is not believing.')
class SelectionError(Exception):
def __init__(self, selection):
logging.error('Invalid selector: {}'.format(selection))
#############
# FUNCTIONS #
#############
def int2(x):
'''
Return integer from base 2 number.
Can accept a list/tuple of 0s and 1s.
'''
if isinstance(x, collections.Iterable):
x = ''.join([str(k) for k in x])
else:
x = str(x)
return int(x, 2)
def int3(x):
'''
Return integer from base 3 number.
Can accept a list/tuple of 0s, 1s and 2s.
'''
if isinstance(x, collections.Iterable):
x = ''.join([str(k) for k in x])
else:
x = str(x)
return int(x, 3)
def selection_parser(selection_list, atom_list):
'''
Selection syntax:
/<chain_id>/<res_num>[<ins_code>]/<atom_name>
HET:<het_id>
Other formats will be rejected, for now.
You can omit fields as long as the number of `/` is correct.
Selections are additive, so if you select chain A with /A//,
adding /A/91/C23 won't make any difference.
'''
final_atom_list = set([])
for selection in selection_list:
#selection_dict = {
# 'chain': None,
# 'residue_number': None,
# 'atom_name': None
#}
chain = None
residue_number = None
insertion_code = ' '
#residue_range = None # TODO
atom_name = None
current_atom_list = atom_list[:]
original_selection = selection
selection = selection.strip()
if selection.startswith('RESNAME:'):
selection = selection.replace('RESNAME:', '').strip()
# RESNAMES ARE MAX LENGTH 3
if len(selection) > 3:
raise SelectionError(original_selection)
current_atom_list = [x for x in current_atom_list if x.get_parent().resname.strip() == selection]
for selected_atom in current_atom_list:
final_atom_list.add(selected_atom)
# SELECT ALL ORGANIC SMALL-MOLECULE LIGANDS
elif selection.startswith('LIGANDS'):
current_atom_list = [x for x in current_atom_list if
x.get_parent().is_polypeptide == False and # MUST NOT BE POLYPEPTIDE
len(x.get_parent().child_list) >= 5 and # MIN NUMBER OF ATOMS
len(x.get_parent().child_list) <= 100 and # MAX NUMBER OF ATOMS
'C' in set([y.element for y in x.get_parent().child_list]) and # MUST CONTAIN CARBON
x.get_parent().resname.strip().upper() not in COMMON_SOLVENTS and # MUST NOT BE COMMON SOLVENT
x.get_parent().resname.strip().upper() not in STANDARD_NUCLEOTIDES and # MUST NOT BE NUCLEOTIDE
not x.get_parent().resname.startswith('+') # MUST NOT BE MODIFIED NUCLEOTIDE
]
for selected_atom in current_atom_list:
final_atom_list.add(selected_atom)
elif selection.startswith('/'):
selection = selection.lstrip('/').split('/')
#print selection
if len(selection) != 3:
raise SelectionError(original_selection)
# CHAIN
if selection[0]:
chain = selection[0]
# RESIDUE AND INS CODE
if selection[1]:
if selection[1].isdigit():
# JUST THE RESNUM
residue_number = int(selection[1])
elif selection[1].isalnum():
# CHECK FOR VALID RESNUM+INSCODE
if selection[1][-1].isalpha() and selection[1][:-1].isdigit():
residue_number = int(selection[1][:-1])
insertion_code = selection[1][-1]
else:
raise SelectionError(original_selection)
else:
raise SelectionError(original_selection)
# ATOM NAME
if selection[2]:
if not selection[2].isalnum() and "'" not in selection[2]:
raise SelectionError(original_selection)
else:
atom_name = selection[2]
# NOW MAKE THE SELECTION WITH BIOPYTHON
if chain:
current_atom_list = [x for x in current_atom_list if x.get_parent().get_parent().id == chain]
if residue_number:
current_atom_list = [x for x in current_atom_list if x.get_parent().id[1] == residue_number and x.get_parent().id[2] == insertion_code]
if atom_name:
current_atom_list = [x for x in current_atom_list if x.name == atom_name]
for selected_atom in current_atom_list:
final_atom_list.add(selected_atom)
else:
raise SelectionError(original_selection)
final_atom_list = list(final_atom_list)
if len(final_atom_list) == 0:
logging.error('Selection was empty.')
sys.exit(1)
return list(final_atom_list)
def make_pymol_string(entity):
'''
Feed me a BioPython atom or BioPython residue.
See `http://pymol.sourceforge.net/newman/user/S0220commands.html`.
chain-identifier/resi-identifier/name-identifier
chain-identifier/resi-identifier/
'''
if isinstance(entity, Atom):
chain = entity.get_parent().get_parent()
residue = entity.get_parent()
atom_name = entity.name
elif isinstance(entity, Residue):
chain = entity.get_parent()
residue = entity
atom_name = ''
else:
raise TypeError('Cannot make a PyMOL string from a non-Atom or Residue object.')
res_num = residue.id[1]
# ADD INSERTION CODE IF NEED BE
if residue.id[2] != ' ':
res_num = str(res_num) + residue.id[2]
macro = '{}/{}/{}'.format(chain.id,
res_num,
atom_name)
return macro
def get_single_bond_neighbour(ob_atom):
'''
'''
for bond in ob.OBAtomBondIter(ob_atom):
if not bond.IsSingle():
continue
current_neighbour = bond.GetNbrAtom(ob_atom)
if current_neighbour.GetAtomicNum() == ob.Hydrogen:
continue
return current_neighbour
return None
def max_mem_usage():
'''
Returns maximum memory usage of the program thus far, in megabytes, as a string.
'''
try:
return str(resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / 1000.0) + ' MB'
except Exception as err:
logging.warn('Resource usage information not available ().'.format(str(err)))
def get_angle(point_a, point_b, point_c):
'''
Get the angle between three points in 3D space.
Points should be supplied in Numpy array format.
http://stackoverflow.com/questions/19729831/angle-between-3-points-in-3d-space
'''
#In pseudo-code, the vector BA (call it v1) is:
#v1 = {A.x - B.x, A.y - B.y, A.z - B.z}
v1 = point_a - point_b
#Similarly the vector BC (call it v2) is:
#v2 = {C.x - B.x, C.y - B.y, C.z - B.z}
v2 = point_c - point_b
#The dot product of v1 and v2 is a function of the cosine of the angle between them
#(it's scaled by the product of their magnitudes). So first normalize v1 and v2:
#v1mag = sqrt(v1.x * v1.x + v1.y * v1.y + v1.z * v1.z)
v1_mag = np.sqrt(v1[0] * v1[0] + v1[1] * v1[1] + v1[2] * v1[2])
#v1norm = {v1.x / v1mag, v1.y / v1mag, v1.z / v1mag}
v1_norm = np.array([v1[0] / v1_mag, v1[1] / v1_mag, v1[2] / v1_mag])
#v2mag = sqrt(v2.x * v2.x + v2.y * v2.y + v2.z * v2.z)
v2_mag = np.sqrt(v2[0] * v2[0] + v2[1] * v2[1] + v2[2] * v2[2])
#v2norm = {v2.x / v2mag, v2.y / v2mag, v2.z / v2mag}
v2_norm = np.array([v2[0] / v2_mag, v2[1] / v2_mag, v2[2] / v2_mag])
#Then calculate the dot product:
#res = v1norm.x * v2norm.x + v1norm.y * v2norm.y + v1norm.z * v2norm.z
res = v1_norm[0] * v2_norm[0] + v1_norm[1] * v2_norm[1] + v1_norm[2] * v2_norm[2]
#And finally, recover the angle:
angle = np.arccos(res)
if np.isnan(angle):
logging.warn('Angle for <{}, {}, {}> was NaN, setting to Pi.'.format(point_a, point_b, point_c))
angle = np.pi
return angle
def group_angle(group, point_coords, degrees=False, signed=False):
'''
Adapted from CREDO: `https://bitbucket.org/blundell/credovi/src/bc337b9191518e10009002e3e6cb44819149980a/credovi/structbio/aromaticring.py?at=default`
`group` should be a dict with Numpy array 'center' and 'normal' attributes.
`point_coords` should be a Numpy array.
'''
cosangle = np.dot(group['normal'], point_coords) / (np.linalg.norm(group['normal']) * np.linalg.norm(point_coords))
# GET THE ANGLE AS RADIANS
rad = np.arccos(cosangle)
if not degrees: return rad
# CONVERT RADIANS INTO DEGREES
else:
# CONVERT INTO A SIGNED ANGLE
if signed: rad = rad -np.pi if rad > np.pi / 2 else rad
# RETURN DEGREES
return rad * 180 / np.pi
def group_group_angle(group, group2, degrees=False, signed=False):
'''
Adapted from CREDO: `https://bitbucket.org/blundell/credovi/src/bc337b9191518e10009002e3e6cb44819149980a/credovi/structbio/aromaticring.py?at=default`
`group` and `group2` should be a dict with Numpy array 'center' and 'normal' attributes.
'''
cosangle = np.dot(group['normal'], group2['normal']) / (np.linalg.norm(group['normal']) * np.linalg.norm(group2['normal']))
# GET THE ANGLE AS RADIANS
rad = np.arccos(cosangle)
if not degrees: return rad
# CONVERT RADIANS INTO DEGREES
else:
# CONVERT INTO A SIGNED ANGLE
if signed: rad = rad -np.pi if rad > np.pi / 2 else rad
# RETURN DEGREES
return rad * 180 / np.pi
## GOLDEN SECTION SPIRAL
## THANK YOU BOSCOH!
## http://boscoh.com/protein/calculating-the-solvent-accessible-surface-area-asa.html
## http://boscoh.com/protein/asapy.html
#def points_on_sphere(n):
# pts = np.empty((int(n), 3))
# n = float(n)
#
# inc = math.pi * (3 - math.sqrt(5))
# off = 2 / n
#
# for k in range(0, int(n)):
#
# y = k * off - 1 + (off / 2)
# r = math.sqrt(1 - y*y)
# phi = k * inc
# pts[k][0] = math.cos(phi) * r
# pts[k][1] = y
# pts[k][2] = math.sin(phi) * r
#
# return pts
# CONTACT FUNCTIONS
def is_hbond(donor, acceptor):
'''
Feed me BioPython atoms.
'''
for hydrogen_coord in donor.h_coords:
h_dist = np.linalg.norm(hydrogen_coord - acceptor.coord)
if h_dist <= VDW_RADII['H'] + acceptor.vdw_radius + VDW_COMP_FACTOR:
if get_angle(donor.coord, hydrogen_coord, acceptor.coord) >= CONTACT_TYPES['hbond']['angle rad']:
return 1
return 0
def is_weak_hbond(donor, acceptor):
'''
Feed me BioPython atoms.
'''
for hydrogen_coord in donor.h_coords:
h_dist = np.linalg.norm(hydrogen_coord - acceptor.coord)
if h_dist <= VDW_RADII['H'] + acceptor.vdw_radius + VDW_COMP_FACTOR:
if get_angle(donor.coord, hydrogen_coord, acceptor.coord) >= CONTACT_TYPES['weak hbond']['angle rad']:
return 1
return 0
def is_halogen_weak_hbond(donor, halogen, ob_mol):
'''
Feed me BioPython atoms and the OpenBabel molecule.
'''
# `nbr` WILL BE A BIOPYTHON ATOM
# ... HOPEFULLY
nbr = ob_to_bio[get_single_bond_neighbour(ob_mol.GetAtomById(bio_to_ob[halogen])).GetId()]
for hydrogen_coord in donor.h_coords:
h_dist = np.linalg.norm(halogen.coord - hydrogen_coord)
if h_dist <= VDW_RADII['H'] + halogen.vdw_radius + VDW_COMP_FACTOR:
if CONTACT_TYPES['weak hbond']['cx angle min rad'] <= get_angle(nbr.coord, halogen.coord, hydrogen_coord) <= CONTACT_TYPES['weak hbond']['cx angle max rad']:
return 1
return 0
def is_xbond(donor, acceptor, ob_mol):
'''
Feed me BioPython atoms and the OpenBabel molecule.
'''
# `nbr` WILL BE A BIOPYTHON ATOM
# ... HOPEFULLY
nbr = ob_to_bio[get_single_bond_neighbour(ob_mol.GetAtomById(bio_to_ob[donor])).GetId()]
theta = get_angle(nbr.coord, donor.coord, acceptor.coord)
if (theta >= CONTACT_TYPES['xbond']['angle theta 1 rad']):
return 1
return 0
def update_atom_sift(atom, addition, contact_type='INTER'):
'''
'''
atom.sift = [x or y for x, y in zip(atom.sift, addition)]
if contact_type == 'INTER':
atom.sift_inter_only = [x or y for x, y in zip(atom.sift_inter_only, addition)]
if 'INTRA' in contact_type:
atom.sift_intra_only = [x or y for x, y in zip(atom.sift_intra_only, addition)]
if 'WATER' in contact_type:
atom.sift_water_only = [x or y for x, y in zip(atom.sift_water_only, addition)]
def update_atom_fsift(atom, addition, contact_type='INTER'):
'''
'''
atom.actual_fsift = [x or y for x, y in zip(atom.actual_fsift, addition)]
if contact_type == 'INTER':
atom.actual_fsift_inter_only = [x or y for x, y in zip(atom.actual_fsift_inter_only, addition)]
if 'INTRA' in contact_type:
atom.actual_fsift_intra_only = [x or y for x, y in zip(atom.actual_fsift_intra_only, addition)]
if 'WATER' in contact_type:
atom.actual_fsift_water_only = [x or y for x, y in zip(atom.actual_fsift_water_only, addition)]
def update_atom_integer_sift(atom, addition, contact_type='INTER'):
'''
'''
atom.integer_sift = [x + y for x, y in zip(atom.sift, addition)]
if contact_type == 'INTER':
atom.integer_sift_inter_only = [x + y for x, y in zip(atom.sift_inter_only, addition)]
if 'INTRA' in contact_type:
atom.integer_sift_intra_only = [x + y for x, y in zip(atom.sift_intra_only, addition)]
if 'WATER' in contact_type:
atom.integer_sift_water_only = [x + y for x, y in zip(atom.sift_water_only, addition)]
def sift_xnor(sift1, sift2):
'''
'''
out = []
for x, y in zip(sift1, sift2):
if x and not y: # TF
out.append(0)
elif not x and not y: # FF
out.append(1)
elif x and y: # TT
out.append(1)
elif not x and y: # FT
out.append(0)
else:
raise ValueError('Invalid SIFts for matching: {} and {}'.format(sift1, sift2))
return out
def sift_match_base3(sift1, sift2):
'''
0 = UNMATCHED
1 = MATCHED
2 = MATCH NOT POSSIBLE
Assuming that sift1 is the potential SIFt, and sift2 is the actual SIFt.
'''
out = []
for x, y in zip(sift1, sift2):
if x and not y: # TF
out.append(0) # UNMATCHED
elif not x and not y: # FF
out.append(2) # MATCH NOT POSSIBLE
elif x and y: # TT
out.append(1) # MATCHED
elif not x and y: # FT
raise SiftMatchError
else:
raise ValueError('Invalid SIFts for matching: {} and {}'.format(sift1, sift2))
return out
def human_sift_match(sift_match, feature_sift=FEATURE_SIFT):
'''
Takes a base-3 SIFt indicating contact matched-ness and converts it to a human readable form.
'''
terms = []
for e, fp in enumerate(sift_match):
if fp == 2: # MATCH NOT POSSIBLE
continue
elif fp == 1:
terms.append('Matched {}'.format(feature_sift[e]))
elif fp == 0:
terms.append('Unmatched {}'.format(feature_sift[e]))
else:
raise ValueError
terms.sort()
return ':'.join(terms)
########
# MAIN #
########
if __name__ == '__main__':
# ARGUMENT PARSING
parser = argparse.ArgumentParser(description='''
############
# ARPEGGIO #
############
A program for calculating interactions,
using only Open Source dependencies.
Dependencies:
- Python (v2.7)
- Numpy
- BioPython (>= v1.60)
- OpenBabel (with Python bindings)
''', formatter_class=argparse.RawTextHelpFormatter)
parser.add_argument('pdb', type=str, help='Path to the PDB file to be analysed.')
selection_group = parser.add_mutually_exclusive_group(required=False)
selection_group.add_argument('-s', '--selection', type=str, nargs='+', help='Select the "ligand" for interactions, using selection syntax: /<chain_id>/<res_num>[<ins_code>]/<atom_name> or RESNAME:<het_id>. Fields can be omitted.')
selection_group.add_argument('-sf', '--selection-file', type=str, help='Selections as above, but listed in a file.')
parser.add_argument('-wh', '--write-hydrogenated', action='store_true', help='Write a PDB file including the added hydrogen coordinates.')
parser.add_argument('-mh', '--minimise-hydrogens', action='store_true', help='Energy minimise OpenBabel added hydrogens.')
parser.add_argument('-ms', '--minimisation-steps', type=int, default=50, help='Number of hydrogen minimisation steps to perform.')
parser.add_argument('-mf', '--minimisation-forcefield', type=str, choices=('MMFF94', 'UFF', 'Ghemical'), default='MMFF94', help='Choose the forcefield to minimise hydrogens with. Ghemical is not recommended.')
parser.add_argument('-mm', '--minimisation-method', type=str, choices=('DistanceGeometry', 'SteepestDescent', 'ConjugateGradients'), default='ConjugateGradients', help='Choose the method to minimise hydrogens with. ConjugateGradients is recommended.')
parser.add_argument('-co', '--vdw-comp', type=float, default=0.1, help='Compensation factor for VdW radii dependent interaction types.')
parser.add_argument('-i', '--interacting', type=float, default=5.0, help='Distance cutoff for grid points to be \'interacting\' with the entity.')
parser.add_argument('-ph', type=float, default=7.4, help='pH for hydrogen addition.')
parser.add_argument('-sa', '--include-sequence-adjacent', action='store_true', help='For intra-polypeptide interactions, include non-bonding interactions between residues that are next to each other in sequence; this is not done by default.')
parser.add_argument('-a', '--use-ambiguities', action='store_true', help='Turn on abiguous definitions for ambiguous contacts.')
parser.add_argument('-he', '--headers', action='store_true', help='Write out column headers in output files.')
#parser.add_argument('-sr', '--solvent_radius', type=float, default=1.4, help='Radius of solvent probe for accessibility calculations.')
#parser.add_argument('-ssp', '--solvent-sphere-points', type=int, default=960, help='Number of points to use for solvent shell spheres for accessibility calculations.')
#parser.add_argument('-st', '--sasa-threshold', type=float, default=1.0, help='Floating point solvent accessible surface area threshold (squared Angstroms) for considering an atom as \'accessible\' or not.')
#parser.add_argument('-ca', '--consider-all', action='store_true', help='Consider all entity/selection atoms, not just solvent accessible ones. If this is set, SASAs won\'t be calculated.')
#parser.add_argument('-spdb', '--sasa-pdb', action='store_true', help='Store a PDB with atom b-factors set based on boolean solvent accessibility.')
parser.add_argument('-op', '--output-postfix', type=str, help='Custom text to append to output filename (but before .extension).')
parser.add_argument('-v', '--verbose', action='store_true', help='Be chatty.')
args = parser.parse_args()
pdb_filename = args.pdb
VDW_COMP_FACTOR = args.vdw_comp
INTERACTING_THRESHOLD = args.interacting
#SOLVENT_RADIUS = args.solvent_radius
#NUM_SOLVENT_SPHERE_POINTS = args.solvent_sphere_points
#SASA_THRESHOLD = args.sasa_threshold
# LOGGING
if args.verbose:
logging.basicConfig(level=logging.INFO, format='%(levelname)s//%(asctime)s.%(msecs).03d//%(message)s', datefmt='%H:%M:%S')
else:
logging.basicConfig(level=logging.WARN, format='%(levelname)s//%(asctime)s.%(msecs).03d//%(message)s', datefmt='%H:%M:%S')
logging.info('Program begin.')
# ADDRESS AMBIGUITIES
if not args.use_ambiguities:
# REMOVE IF NOT USING THE AMBIGUITIES (DEFAULT)
# REMOVE FROM SMARTS DEFINITIONS
ATOM_TYPES['hbond acceptor'].pop('NH2 terminal amide', None)
ATOM_TYPES['hbond donor'].pop('oxygen amide term', None)
ATOM_TYPES['xbond acceptor'].pop('NH2 terminal amide', None)
ATOM_TYPES['weak hbond acceptor'].pop('NH2 terminal amide', None)
# REMOVE FROM PROTEIN ATOM DEFINITIONS
PROT_ATOM_TYPES['hbond acceptor'] = [x for x in PROT_ATOM_TYPES['hbond acceptor'] if x not in ('ASNND2', 'GLNNE2', 'HISCE1', 'HISCD2')]
PROT_ATOM_TYPES['hbond donor'] = [x for x in PROT_ATOM_TYPES['hbond donor'] if x not in ('ASNOD1', 'GLNOE1', 'HISCE1', 'HISCD2')]
PROT_ATOM_TYPES['xbond acceptor'] = [x for x in PROT_ATOM_TYPES['xbond acceptor'] if x not in ('ASNND2', 'GLNNE2', 'HISCE1', 'HISCD2')]
PROT_ATOM_TYPES['weak hbond acceptor'] = [x for x in PROT_ATOM_TYPES['weak hbond acceptor'] if x not in ('ASNND2', 'GLNNE2', 'HISCE1', 'HISCD2')]
# LOAD STRUCTURE (BIOPYTHON)
pdb_parser = PDBParser()
s = pdb_parser.get_structure('structure', pdb_filename)
s_atoms = list(s.get_atoms())
logging.info('Loaded PDB structure (BioPython)')
# CHECK FOR HYDROGENS IN THE INPUT STRUCTURE
input_has_hydrogens = False
hydrogens = [x for x in s_atoms if x.element == 'H']
if hydrogens:
logging.info('Detected that the input structure contains hydrogens. Hydrogen addition will be skipped.')
input_has_hydrogens = True
# LOAD STRUCTURE (OPENBABEL)
ob_conv = ob.OBConversion()
ob_conv.SetInFormat('pdb')
mol = ob.OBMol()
ob_conv.ReadFile(mol, pdb_filename)
logging.info('Loaded PDB structure (OpenBabel)')
# RENAME FOR OUTPUTS IF REQUESTED
if args.output_postfix:
pdb_filename = pdb_filename.replace('.pdb', args.output_postfix + '.pdb')
# CHECK THAT EACH ATOM HAS A UNIQUE SERIAL NUMBER
all_serials = [x.serial_number for x in s_atoms]
if len(all_serials) > len(set(all_serials)):
raise AtomSerialError
# MAPPING OB ATOMS TO BIOPYTHON ATOMS AND VICE VERSA
# FIRST MAP PDB SERIAL NUMBERS TO BIOPYTHON ATOMS FOR SPEED LATER
# THIS AVOIDS LOOPING THROUGH `s_atoms` MANY TIMES
serial_to_bio = {x.serial_number: x for x in s_atoms}
# DICTIONARIES FOR CONVERSIONS
ob_to_bio = {}
bio_to_ob = {}
for ob_atom in ob.OBMolAtomIter(mol):
serial = ob_atom.GetResidue().GetSerialNum(ob_atom)
# MATCH TO THE BIOPYTHON ATOM BY SERIAL NUMBER
try:
biopython_atom = serial_to_bio[serial]
except KeyError:
# ERRORWORTHY IF WE CAN'T MATCH AN OB ATOM TO A BIOPYTHON ONE
raise OBBioMatchError(serial)
# `Id` IS A UNIQUE AND STABLE ID IN OPENBABEL
# CAN RECOVER THE ATOM WITH `mol.GetAtomById(id)`
ob_to_bio[ob_atom.GetId()] = biopython_atom
bio_to_ob[biopython_atom] = ob_atom.GetId()
logging.info('Mapped OB to BioPython atoms and vice-versa.')
# ADD EMPTY DATA STRUCTURES FOR TAGGED ATOM DATA
# IN A SINGLE ITERATION
for atom in s_atoms:
# FOR ATOM TYPING VIA OPENBABEL
atom.atom_types = set([])
# LIST FOR EACH ATOM TO STORE EXPLICIT HYDROGEN COORDINATES
atom.h_coords = []
# DETECT METALS
if atom.element.upper() in METALS:
atom.is_metal = True
else:
atom.is_metal = False
# DETECT HALOGENS
if atom.element.upper() in HALOGENS:
atom.is_halogen = True
else:
atom.is_halogen = False
# ADD EXPLICIT HYDROGEN COORDS FOR H-BONDING INTERACTIONS
# ADDING HYDROGENS DOESN'T SEEM TO INTERFERE WITH ATOM SERIALS (THEY GET ADDED AS 0)
# SO WE CAN STILL GET BACK TO THE PERSISTENT BIOPYTHON ATOMS THIS WAY.
if not input_has_hydrogens:
mol.AddHydrogens(False, True, args.ph) # polaronly, correctForPH, pH
logging.info('Added hydrogens.')
# ATOM TYPING VIA OPENBABEL
# ITERATE OVER ATOM TYPE SMARTS DEFINITIONS
for atom_type, smartsdict in ATOM_TYPES.items():
#logging.info('Typing: {}'.format(atom_type))
# FOR EACH ATOM TYPE SMARTS STRING
for smarts in smartsdict.values():
#logging.info('Smarts: {}'.format(smarts))
# GET OPENBABEL ATOM MATCHES TO THE SMARTS PATTERN
ob_smart = ob.OBSmartsPattern()
ob_smart.Init(str(smarts))
#logging.info('Initialised for: {}'.format(smarts))
ob_smart.Match(mol)
#logging.info('Matched for: {}'.format(smarts))
matches = [x for x in ob_smart.GetMapList()]
#logging.info('List comp matches: {}'.format(smarts))
if matches:
# REDUCE TO A SINGLE LIST
matches = set(functools.reduce(operator.add, matches))
#logging.info('Set reduce matches: {}'.format(smarts))
for match in matches:
atom = mol.GetAtom(match)
ob_to_bio[atom.GetId()].atom_types.add(atom_type)
#logging.info('Assigned types: {}'.format(smarts))
# ALL WATER MOLECULES ARE HYDROGEN BOND DONORS AND ACCEPTORS
for atom in (x for x in s_atoms if x.get_full_id()[3][0] == 'W'):
atom.atom_types.add('hbond acceptor')
atom.atom_types.add('hbond donor')
# OVERRIDE PROTEIN ATOM TYPING FROM DICTIONARY
for residue in s.get_residues():
if residue.resname in STD_RES:
for atom in residue.child_list:
# REMOVE TYPES IF ALREADY ASSIGNED FROM SMARTS
for atom_type in PROT_ATOM_TYPES.keys():
atom.atom_types.discard(atom_type)
# ADD ATOM TYPES FROM DICTIONARY
for atom_type, atom_ids in PROT_ATOM_TYPES.items():
atom_id = residue.resname.strip() + atom.name.strip()
if atom_id in atom_ids:
atom.atom_types.add(atom_type)
with open(pdb_filename.replace('.pdb', '.atomtypes'), 'w') as fo:
if args.headers:
fo.write('{}\n'.format('\t'.join(
['atom', 'atom_types']
)))
for atom in s_atoms:
fo.write('{}\n'.format('\t'.join([str(x) for x in [make_pymol_string(atom), sorted(tuple(atom.atom_types))]])))
logging.info('Typed atoms.')
# DETERMINE ATOM VALENCES AND EXPLICIT HYDROGEN COUNTS
for ob_atom in ob.OBMolAtomIter(mol):
if not input_has_hydrogens:
if ob_atom.GetAtomicNum() == ob.Hydrogen:
continue
# `http://openbabel.org/api/2.3/classOpenBabel_1_1OBAtom.shtml`
# CURRENT NUMBER OF EXPLICIT CONNECTIONS
valence = ob_atom.GetExplicitDegree()
# MAXIMUM NUMBER OF CONNECTIONS EXPECTED
implicit_valence = ob_atom.GetImplicitHCount()
# BOND ORDER
bond_order = ob_atom.GetExplicitValence()
# NUMBER OF BOUND HYDROGENS
num_hydrogens = ob_atom.ExplicitHydrogenCount()
# ELEMENT NUMBER
atomic_number = ob_atom.GetAtomicNum()
# FORMAL CHARGE
formal_charge = ob_atom.GetFormalCharge()
bio_atom = ob_to_bio[ob_atom.GetId()]
bio_atom.valence = valence
bio_atom.implicit_valence = implicit_valence
bio_atom.num_hydrogens = num_hydrogens
bio_atom.bond_order = bond_order
bio_atom.atomic_number = atomic_number
bio_atom.formal_charge = formal_charge
logging.info('Determined atom explicit and implicit valences, bond orders, atomic numbers, formal charge and number of bound hydrogens.')
# INITIALISE ATOM FULL SIFT
# INITIALISE ATOM FEATURE SIFT AND
# DETERMINE ATOM POTENTIAL FEATURE SIFT
# 5: 0: HBOND
# 6: 1: WEAK_HBOND
# 7: 2: HALOGEN_BOND
# 8: 3: IONIC
# 9: 4: METAL_COMPLEX
#10: 5: AROMATIC
#11: 6: HYDROPHOBIC
#12: 7: CARBONYL
# 8: POLAR - H-BONDS WITHOUT ANGLES
# 9: WEAK POLAR - WEAK H-BONDS WITHOUT ANGLES
# ALSO INITIALISE ATOM NUMBER OF POTENTIAL HBONDS/POLAR
# AND NUMBER OF ACTUAL HBONDS/POLAR
for atom in s_atoms:
# INTEGER SIFTS
atom.integer_sift = [0] * 15
atom.integer_sift_inter_only = [0] * 15
atom.integer_sift_intra_only = [0] * 15
atom.integer_sift_water_only = [0] * 15
# BINARY SIFTS
atom.sift = [0] * 15
atom.sift_inter_only = [0] * 15
atom.sift_intra_only = [0] * 15
atom.sift_water_only = [0] * 15
atom.potential_fsift = [0] * 10
atom.actual_fsift = [0] * 10
atom.actual_fsift_inter_only = [0] * 10
atom.actual_fsift_intra_only = [0] * 10
atom.actual_fsift_water_only = [0] * 10
atom.potential_hbonds = 0
atom.potential_polars = 0
atom.actual_hbonds = 0
atom.actual_polars = 0
atom.actual_hbonds_inter_only = 0
atom.actual_polars_inter_only = 0
atom.actual_hbonds_intra_only = 0
atom.actual_polars_intra_only = 0
atom.actual_hbonds_water_only = 0
atom.actual_polars_water_only = 0
# ATOM POTENTIAL FEATURE SIFT
# 0: HBOND
if 'hbond acceptor' in atom.atom_types or 'hbond donor' in atom.atom_types:
atom.potential_fsift[0] = 1
if 'hbond acceptor' in atom.atom_types:
# NUMBER OF LONE PAIRS
lone_pairs = VALENCE[atom.atomic_number] - atom.bond_order - atom.formal_charge
if lone_pairs != 0:
lone_pairs = lone_pairs / 2
atom.potential_hbonds = atom.potential_hbonds + lone_pairs
atom.potential_polars = atom.potential_polars + lone_pairs
if 'hbond donor' in atom.atom_types:
atom.potential_hbonds = atom.potential_hbonds + atom.num_hydrogens
atom.potential_polars = atom.potential_polars + atom.num_hydrogens
# 1: WEAK HBOND
if 'weak hbond acceptor' in atom.atom_types or 'weak hbond donor' in atom.atom_types or 'hbond donor' in atom.atom_types or 'hbond acceptor' in atom.atom_types or atom.is_halogen:
atom.potential_fsift[1] = 1
# 2: HALOGEN BOND
if 'xbond acceptor' in atom.atom_types or 'xbond donor' in atom.atom_types:
atom.potential_fsift[2] = 1
# 3: IONIC
if 'pos ionisable' in atom.atom_types or 'neg ionisable' in atom.atom_types: