def generate_solvated_hybrid_test_topology(current_mol_name="naphthalene",
proposed_mol_name="benzene",
current_mol_smiles=None,
proposed_mol_smiles=None,
vacuum=False,
render_atom_mapping=False):
"""
This function will generate a topology proposal, old positions, and new positions with a geometry proposal (either vacuum or solvated) given a set of input iupacs or smiles.
The function will (by default) read the iupac names first. If they are set to None, then it will attempt to read a set of current and new smiles.
An atom mapping pdf will be generated if specified.
Arguments
----------
current_mol_name : str, optional
name of the first molecule
proposed_mol_name : str, optional
name of the second molecule
current_mol_smiles : str (default None)
current mol smiles
proposed_mol_smiles : str (default None)
proposed mol smiles
vacuum: bool (default False)
whether to render a vacuum or solvated topology_proposal
render_atom_mapping : bool (default False)
whether to render the atom map of the current_mol_name and proposed_mol_name
Returns
-------
topology_proposal : perses.rjmc.topology_proposal
The topology proposal representing the transformation
current_positions : np.array, unit-bearing
The positions of the initial system
new_positions : np.array, unit-bearing
The positions of the new system
"""
import simtk.openmm.app as app
from openmoltools import forcefield_generators
from openeye import oechem
from openmoltools.openeye import iupac_to_oemol, generate_conformers, smiles_to_oemol
from openmoltools import forcefield_generators
import perses.utils.openeye as openeye
from perses.utils.data import get_data_filename
from perses.rjmc.topology_proposal import TopologyProposal, SystemGenerator, SmallMoleculeSetProposalEngine
import simtk.unit as unit
from perses.rjmc.geometry import FFAllAngleGeometryEngine
if current_mol_name != None and proposed_mol_name != None:
try:
old_oemol, new_oemol = iupac_to_oemol(
current_mol_name), iupac_to_oemol(proposed_mol_name)
old_smiles = oechem.OECreateSmiString(
old_oemol,
oechem.OESMILESFlag_DEFAULT | oechem.OESMILESFlag_Hydrogens)
new_smiles = oechem.OECreateSmiString(
new_oemol,
oechem.OESMILESFlag_DEFAULT | oechem.OESMILESFlag_Hydrogens)
except:
raise Exception(
f"either {current_mol_name} or {proposed_mol_name} is not compatible with 'iupac_to_oemol' function!"
)
elif current_mol_smiles != None and proposed_mol_smiles != None:
try:
old_oemol, new_oemol = smiles_to_oemol(
current_mol_smiles), smiles_to_oemol(proposed_mol_smiles)
old_smiles = oechem.OECreateSmiString(
old_oemol,
oechem.OESMILESFlag_DEFAULT | oechem.OESMILESFlag_Hydrogens)
new_smiles = oechem.OECreateSmiString(
new_oemol,
oechem.OESMILESFlag_DEFAULT | oechem.OESMILESFlag_Hydrogens)
except:
raise Exception(f"the variables are not compatible")
else:
raise Exception(
f"either current_mol_name and proposed_mol_name must be specified as iupacs OR current_mol_smiles and proposed_mol_smiles must be specified as smiles strings."
)
old_oemol, old_system, old_positions, old_topology = openeye.createSystemFromSMILES(
old_smiles, title="MOL")
#correct the old positions
old_positions = openeye.extractPositionsFromOEMol(old_oemol)
old_positions = old_positions.in_units_of(unit.nanometers)
new_oemol, new_system, new_positions, new_topology = openeye.createSystemFromSMILES(
new_smiles, title="NEW")
ffxml = forcefield_generators.generateForceFieldFromMolecules(
[old_oemol, new_oemol])
old_oemol.SetTitle('MOL')
new_oemol.SetTitle('MOL')
old_topology = forcefield_generators.generateTopologyFromOEMol(old_oemol)
new_topology = forcefield_generators.generateTopologyFromOEMol(new_oemol)
if not vacuum:
nonbonded_method = app.PME
barostat = openmm.MonteCarloBarostat(1.0 * unit.atmosphere,
300.0 * unit.kelvin, 50)
else:
nonbonded_method = app.NoCutoff
barostat = None
gaff_xml_filename = get_data_filename("data/gaff.xml")
system_generator = SystemGenerator(
[gaff_xml_filename, 'amber99sbildn.xml', 'tip3p.xml'],
barostat=barostat,
forcefield_kwargs={
'removeCMMotion': False,
'nonbondedMethod': nonbonded_method,
'constraints': app.HBonds,
'hydrogenMass': 4.0 * unit.amu
})
system_generator._forcefield.loadFile(StringIO(ffxml))
proposal_engine = SmallMoleculeSetProposalEngine([old_smiles, new_smiles],
system_generator,
residue_name='MOL')
geometry_engine = FFAllAngleGeometryEngine(metadata=None,
use_sterics=False,
n_bond_divisions=1000,
n_angle_divisions=180,
n_torsion_divisions=360,
verbose=True,
storage=None,
bond_softening_constant=1.0,
angle_softening_constant=1.0,
neglect_angles=False)
if not vacuum:
#now to solvate
modeller = app.Modeller(old_topology, old_positions)
hs = [
atom for atom in modeller.topology.atoms()
if atom.element.symbol in ['H']
and atom.residue.name not in ['MOL', 'OLD', 'NEW']
]
modeller.delete(hs)
modeller.addHydrogens(forcefield=system_generator._forcefield)
modeller.addSolvent(system_generator._forcefield,
model='tip3p',
padding=9.0 * unit.angstroms)
solvated_topology = modeller.getTopology()
solvated_positions = modeller.getPositions()
solvated_positions = unit.quantity.Quantity(value=np.array([
list(atom_pos) for atom_pos in
solvated_positions.value_in_unit_system(unit.md_unit_system)
]),
unit=unit.nanometers)
solvated_system = system_generator.build_system(solvated_topology)
#now to create proposal
top_proposal = proposal_engine.propose(
current_system=solvated_system,
current_topology=solvated_topology,
current_mol=old_oemol,
proposed_mol=new_oemol)
new_positions, _ = geometry_engine.propose(top_proposal,
solvated_positions, beta)
if render_atom_mapping:
from perses.utils.smallmolecules import render_atom_mapping
print(
f"new_to_old: {proposal_engine.non_offset_new_to_old_atom_map}"
)
render_atom_mapping(f"{old_smiles}to{new_smiles}.png", old_oemol,
new_oemol,
proposal_engine.non_offset_new_to_old_atom_map)
return top_proposal, solvated_positions, new_positions
else:
vacuum_system = system_generator.build_system(old_topology)
top_proposal = proposal_engine.propose(current_system=vacuum_system,
current_topology=old_topology,
current_mol=old_oemol,
proposed_mol=new_oemol)
new_positions, _ = geometry_engine.propose(top_proposal, old_positions,
beta)
if render_atom_mapping:
from perses.utils.smallmolecules import render_atom_mapping
print(f"new_to_old: {top_proposal._new_to_old_atom_map}")
render_atom_mapping(f"{old_smiles}to{new_smiles}.png", old_oemol,
new_oemol, top_proposal._new_to_old_atom_map)
return top_proposal, old_positions, new_positions
system_generator = SystemGenerator(
['gaff2.xml'],
barostat=None,
forcefield_kwargs={
'removeCMMotion': False,
'ewaldErrorTolerance': 1e-4,
'nonbondedMethod': app.NoCutoff,
'constraints': app.HBonds,
'hydrogenMass': 4 * unit.amus
})
# In[ ]:
# In[ ]:
old_mol, old_system, old_pos, old_top = createSystemFromSMILES('CCCCO')
old_system = system_generator.build_system(old_top)
new_mol, new_system, new_pos, new_top = createSystemFromSMILES('CCCCS')
new_system = system_generator.build_system(new_top)
# In[ ]:
num_old_constraints = old_system.getNumConstraints()
print(num_old_constraints)
for i in range(num_old_constraints):
print(old_system.getConstraintParameters(i))
# In[ ]:
num_old_constraints = new_system.getNumConstraints()