def generate_atp(phase='vacuum'):
"""
modify the AlanineDipeptideVacuum test system to be parametrized with amber14ffsb in vac or solvent (tip3p)
"""
import openmmtools.testsystems as ts
atp = ts.AlanineDipeptideVacuum(constraints=app.HBonds,
hydrogenMass=4 * unit.amus)
forcefield_files = [
'gaff.xml', 'amber14/protein.ff14SB.xml', 'amber14/tip3p.xml'
]
if phase == 'vacuum':
barostat = None
system_generator = SystemGenerator(forcefield_files,
barostat=barostat,
forcefield_kwargs={
'removeCMMotion': False,
'ewaldErrorTolerance': 1e-4,
'nonbondedMethod': app.NoCutoff,
'constraints': app.HBonds,
'hydrogenMass': 4 * unit.amus
})
atp.system = system_generator.build_system(
atp.topology) #update the parametrization scheme to amberff14sb
elif phase == 'solvent':
barostat = openmm.MonteCarloBarostat(1.0 * unit.atmosphere,
300 * unit.kelvin, 50)
system_generator = SystemGenerator(forcefield_files,
barostat=barostat,
forcefield_kwargs={
'removeCMMotion': False,
'ewaldErrorTolerance': 1e-4,
'nonbondedMethod': app.PME,
'constraints': app.HBonds,
'hydrogenMass': 4 * unit.amus
})
if phase == 'solvent':
modeller = app.Modeller(atp.topology, atp.positions)
modeller.addSolvent(system_generator._forcefield,
model='tip3p',
padding=9 * unit.angstroms,
ionicStrength=0.15 * unit.molar)
solvated_topology = modeller.getTopology()
solvated_positions = modeller.getPositions()
# canonicalize the solvated positions: turn tuples into np.array
atp.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)
atp.topology = solvated_topology
atp.system = system_generator.build_system(atp.topology)
return atp, system_generator
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
def create_systems(topologies_dict,
positions_dict,
output_directory,
project_prefix,
solvate=True):
"""
Generate the systems ready for equilibrium simulations from a dictionary of topologies and positions
Parameters
----------
topologies_dict : dict of str: app.Topoology
A dictionary of the topologies to prepare, indexed by SMILES strings
positions_dict : dict of str: unit.Quantity array
A dictionary of positions for the corresponding topologies, indexed by SMILES strings
output_directory : str
Location of output files
project_prefix : str
What to prepend to the names of files for this run
solvate : bool, default True
Whether to solvate the systems
"""
barostat = openmm.MonteCarloBarostat(1.0 * unit.atmosphere, temperature,
50)
system_generator = SystemGenerator(
[
'amber14/protein.ff14SB.xml', 'gaff.xml', 'amber14/tip3p.xml',
'MCL1_ligands.xml'
],
barostat=barostat,
forcefield_kwargs={
'nonbondedMethod': app.PME,
'constraints': app.HBonds,
'hydrogenMass': 4 * unit.amus
},
use_antechamber=False)
list_of_smiles = list(topologies_dict.keys())
initial_smiles = list_of_smiles[0]
initial_topology = topologies_dict[initial_smiles]
initial_positions = positions_dict[initial_smiles]
if solvate:
solvated_initial_positions, solvated_topology, solvated_system = solvate_system(
initial_topology.to_openmm(), initial_positions, system_generator)
else:
solvated_initial_positions = initial_positions
solvated_topology = initial_topology
solvated_system = system_generator.build_system(solvated_topology)
md_topology = md.Topology.from_openmm(solvated_topology)
if solvate:
num_added = md_topology.n_residues - initial_topology.n_residues
if not os.path.exists(output_directory):
os.mkdir(output_directory)
np.save("{}/{}_{}_initial.npy".format(output_directory, project_prefix, 0),
(solvated_initial_positions, md_topology, solvated_system,
initial_smiles))
for i in tqdm.trange(1, len(list_of_smiles)):
smiles = list_of_smiles[i]
topology = topologies_dict[smiles]
positions = positions_dict[smiles]
if solvate:
solvated_positions, solvated_topology, solvated_system = solvate_system(
topology.to_openmm(),
positions,
system_generator,
padding=None,
num_added=num_added)
else:
solvated_positions = initial_positions
solvated_topology = initial_topology
solvated_system = system_generator.build_system(solvated_topology)
np.save(
"{}/{}_{}_initial.npy".format(output_directory, project_prefix, i),
(solvated_positions, md.Topology.from_openmm(solvated_topology),
solvated_system, smiles))
class NonequilibriumFEPSetup(object):
"""
This class is a helper class for nonequilibrium FEP. It generates the input objects that are necessary for the two
legs of a relative FEP calculation. For each leg, that is a TopologyProposal, old_positions, and new_positions.
Importantly, it ensures that the atom maps in the solvent and complex phases match correctly.
"""
def __init__(self,
protein_pdb_filename,
ligand_file,
old_ligand_index,
new_ligand_index,
forcefield_files,
pressure=1.0 * unit.atmosphere,
temperature=300.0 * unit.kelvin,
solvent_padding=9.0 * unit.angstroms):
"""
Initialize a NonequilibriumFEPSetup object
Parameters
----------
protein_pdb_filename : str
The name of the protein pdb file
ligand_file : str
the name of the ligand file (any openeye supported format)
ligand_smiles : list of two str
The SMILES strings representing the two ligands
forcefield_files : list of str
The list of ffxml files that contain the forcefields that will be used
pressure : Quantity, units of pressure
Pressure to use in the barostat
temperature : Quantity, units of temperature
Temperature to use for the Langevin integrator
solvent_padding : Quantity, units of length
The amount of padding to use when adding solvent
"""
self._protein_pdb_filename = protein_pdb_filename
self._pressure = pressure
self._temperature = temperature
self._barostat_period = 50
self._padding = solvent_padding
self._ligand_file = ligand_file
self._old_ligand_index = old_ligand_index
self._new_ligand_index = new_ligand_index
self._old_ligand_oemol = self.load_sdf(self._ligand_file,
index=self._old_ligand_index)
self._new_ligand_oemol = self.load_sdf(self._ligand_file,
index=self._new_ligand_index)
self._old_ligand_positions = extractPositionsFromOEMOL(
self._old_ligand_oemol)
ffxml = forcefield_generators.generateForceFieldFromMolecules(
[self._old_ligand_oemol, self._new_ligand_oemol])
self._old_ligand_oemol.SetTitle("MOL")
self._new_ligand_oemol.SetTitle("MOL")
self._new_ligand_smiles = oechem.OECreateSmiString(
self._new_ligand_oemol,
oechem.OESMILESFlag_DEFAULT | oechem.OESMILESFlag_Hydrogens)
#self._old_ligand_smiles = '[H]c1c(c(c(c(c1N([H])c2nc3c(c(n2)OC([H])([H])C4(C(C(C(C(C4([H])[H])([H])[H])([H])[H])([H])[H])([H])[H])[H])nc(n3[H])[H])[H])[H])S(=O)(=O)C([H])([H])[H])[H]'
self._old_ligand_smiles = oechem.OECreateSmiString(
self._old_ligand_oemol,
oechem.OESMILESFlag_DEFAULT | oechem.OESMILESFlag_Hydrogens)
print(self._new_ligand_smiles)
print(self._old_ligand_smiles)
self._old_ligand_topology = forcefield_generators.generateTopologyFromOEMol(
self._old_ligand_oemol)
self._old_ligand_md_topology = md.Topology.from_openmm(
self._old_ligand_topology)
self._new_ligand_topology = forcefield_generators.generateTopologyFromOEMol(
self._new_ligand_oemol)
self._new_liands_md_topology = md.Topology.from_openmm(
self._new_ligand_topology)
protein_pdbfile = open(self._protein_pdb_filename, 'r')
pdb_file = app.PDBFile(protein_pdbfile)
protein_pdbfile.close()
self._protein_topology_old = pdb_file.topology
self._protein_md_topology_old = md.Topology.from_openmm(
self._protein_topology_old)
self._protein_positions_old = pdb_file.positions
self._forcefield = app.ForceField(*forcefield_files)
self._forcefield.loadFile(StringIO(ffxml))
print("Generated forcefield")
self._complex_md_topology_old = self._protein_md_topology_old.join(
self._old_ligand_md_topology)
self._complex_topology_old = self._complex_md_topology_old.to_openmm()
n_atoms_complex_old = self._complex_topology_old.getNumAtoms()
n_atoms_protein_old = self._protein_topology_old.getNumAtoms()
self._complex_positions_old = unit.Quantity(np.zeros(
[n_atoms_complex_old, 3]),
unit=unit.nanometers)
self._complex_positions_old[:
n_atoms_protein_old, :] = self._protein_positions_old
self._complex_positions_old[
n_atoms_protein_old:, :] = self._old_ligand_positions
if pressure is not None:
barostat = openmm.MonteCarloBarostat(self._pressure,
self._temperature,
self._barostat_period)
self._system_generator = SystemGenerator(
forcefield_files,
barostat=barostat,
forcefield_kwargs={'nonbondedMethod': app.PME})
else:
self._system_generator = SystemGenerator(forcefield_files)
#self._complex_proposal_engine = TwoMoleculeSetProposalEngine(self._old_ligand_smiles, self._new_ligand_smiles, self._system_generator, residue_name="MOL")
self._complex_proposal_engine = TwoMoleculeSetProposalEngine(
self._old_ligand_oemol,
self._new_ligand_oemol,
self._system_generator,
residue_name="MOL")
self._geometry_engine = FFAllAngleGeometryEngine()
self._complex_topology_old_solvated, self._complex_positions_old_solvated, self._complex_system_old_solvated = self._solvate_system(
self._complex_topology_old, self._complex_positions_old)
self._complex_md_topology_old_solvated = md.Topology.from_openmm(
self._complex_topology_old_solvated)
print(self._complex_proposal_engine._smiles_list)
beta = 1.0 / (kB * temperature)
self._complex_topology_proposal = self._complex_proposal_engine.propose(
self._complex_system_old_solvated,
self._complex_topology_old_solvated)
self._complex_positions_new_solvated, _ = self._geometry_engine.propose(
self._complex_topology_proposal,
self._complex_positions_old_solvated, beta)
#now generate the equivalent objects for the solvent phase. First, generate the ligand-only topologies and atom map
self._solvent_topology_proposal, self._old_solvent_positions = self._generate_ligand_only_topologies(
self._complex_positions_old_solvated,
self._complex_positions_new_solvated)
self._new_solvent_positions, _ = self._geometry_engine.propose(
self._solvent_topology_proposal, self._old_solvent_positions, beta)
def load_sdf(self, sdf_filename, index=0):
"""
Load an SDF file into an OEMol. Since SDF files can contain multiple molecules, an index can be provided as well.
Parameters
----------
sdf_filename : str
The name of the SDF file
index : int, default 0
The index of the molecule in the SDF file
Returns
-------
mol : openeye.oechem.OEMol object
The loaded oemol object
"""
ifs = oechem.oemolistream()
ifs.open(sdf_filename)
#get the list of molecules
mol_list = [oechem.OEMol(mol) for mol in ifs.GetOEMols()]
#we'll always take the first for now
mol_to_return = mol_list[index]
return mol_to_return
def _solvate_system(self, topology, positions, model='tip3p'):
"""
Generate a solvated topology, positions, and system for a given input topology and positions.
For generating the system, the forcefield files provided in the constructor will be used.
Parameters
----------
topology : app.Topology
Topology of the system to solvate
positions : [n, 3] ndarray of Quantity nm
the positions of the unsolvated system
Returns
-------
solvated_topology : app.Topology
Topology of the system with added waters
solvated_positions : [n + 3(n_waters), 3] ndarray of Quantity nm
Solvated positions
solvated_system : openmm.System
The parameterized system, containing a barostat if one was specified.
"""
modeller = app.Modeller(topology, positions)
hs = [
atom for atom in modeller.topology.atoms()
if atom.element.symbol in ['H'] and atom.residue.name != "MOL"
]
modeller.delete(hs)
modeller.addHydrogens(forcefield=self._forcefield)
print("preparing to add solvent")
modeller.addSolvent(self._forcefield,
model=model,
padding=self._padding)
solvated_topology = modeller.getTopology()
solvated_positions = modeller.getPositions()
print("solvent added, parameterizing")
solvated_system = self._system_generator.build_system(
solvated_topology)
print("System parameterized")
return solvated_topology, solvated_positions, solvated_system
def _generate_ligand_only_topologies(self, old_positions, new_positions):
"""
This method generates ligand-only topologies and positions from a TopologyProposal containing a solvated complex.
The output of this method is then used when building the solvent-phase simulation with the same atom map.
Parameters
----------
topology_proposal : perses.rjmc.TopologyProposal
TopologyProposal representing the solvated complex transformation
Returns
-------
old_ligand_topology : app.Topology
The old topology without the receptor or solvent
new_ligand_topology : app.Topology
The new topology without the receptor or solvent
old_ligand_positions : [m, 3] ndarray of Quantity nm
The positions of the old ligand without receptor or solvent
new_ligand_positions : [n, 3] ndarray of Quantity nm
The positions of the new ligand without receptor or solvent
atom_map : dict of int: it
The mapping between the two topologies without ligand or solvent.
"""
old_complex = md.Topology.from_openmm(
self._complex_topology_proposal.old_topology)
new_complex = md.Topology.from_openmm(
self._complex_topology_proposal.new_topology)
complex_atom_map = self._complex_topology_proposal.old_to_new_atom_map
old_mol_start_index, old_mol_len = self._complex_proposal_engine._find_mol_start_index(
old_complex.to_openmm())
new_mol_start_index, new_mol_len = self._complex_proposal_engine._find_mol_start_index(
new_complex.to_openmm())
old_pos = unit.Quantity(np.zeros([len(old_positions), 3]),
unit=unit.nanometers)
old_pos[:, :] = old_positions
old_ligand_positions = old_pos[old_mol_start_index:(
old_mol_start_index + old_mol_len), :]
new_ligand_positions = new_positions[new_mol_start_index:(
new_mol_start_index + new_mol_len), :]
#atom_map_adjusted = {}
#loop through the atoms in the map. If the old index is creater than the old_mol_start_index but less than that
#plus the old mol length, then it is valid to include its adjusted value in the map.
#for old_idx, new_idx in complex_atom_map.items():
# if old_idx > old_mol_start_index and old_idx < old_mol_len + old_mol_start_index:
# atom_map_adjusted[old_idx - old_mol_len] = new_idx - new_mol_start_index
#subset the topologies:
old_ligand_topology = old_complex.subset(
old_complex.select("resname == 'MOL' "))
new_ligand_topology = new_complex.subset(
new_complex.select("resname == 'MOL' "))
#solvate the old ligand topology:
old_solvated_topology, old_solvated_positions, old_solvated_system = self._solvate_system(
old_ligand_topology.to_openmm(), old_ligand_positions)
old_solvated_md_topology = md.Topology.from_openmm(
old_solvated_topology)
#now remove the old ligand, leaving only the solvent
solvent_only_topology = old_solvated_md_topology.subset(
old_solvated_md_topology.select("water"))
#append the solvent to the new ligand-only topology:
new_solvated_ligand_md_topology = new_ligand_topology.join(
solvent_only_topology)
nsl, b = new_solvated_ligand_md_topology.to_dataframe()
#dirty hack because new_solvated_ligand_md_topology.to_openmm() was throwing bond topology error
new_solvated_ligand_md_topology = md.Topology.from_dataframe(nsl, b)
new_solvated_ligand_omm_topology = new_solvated_ligand_md_topology.to_openmm(
)
new_solvated_ligand_omm_topology.setPeriodicBoxVectors(
old_solvated_topology.getPeriodicBoxVectors())
#create the new ligand system:
new_solvated_system = self._system_generator.build_system(
new_solvated_ligand_omm_topology)
new_to_old_atom_map = {
complex_atom_map[x] - new_mol_start_index: x - old_mol_start_index
for x in old_complex.select("resname == 'MOL' ")
if x in complex_atom_map.keys()
}
#adjust the atom map to account for the presence of solvent degrees of freedom:
#By design, all atoms after the ligands are water, and should be mapped.
n_water_atoms = solvent_only_topology.to_openmm().getNumAtoms()
for i in range(n_water_atoms):
new_to_old_atom_map[new_mol_len + i] = old_mol_len + i
#change the map to accomodate the TP:
#new_to_old_atom_map = {value : key for key, value in atom_map_adjusted.items()}
#make a TopologyProposal
ligand_topology_proposal = TopologyProposal(
new_topology=new_solvated_ligand_omm_topology,
new_system=new_solvated_system,
old_topology=old_solvated_topology,
old_system=old_solvated_system,
new_to_old_atom_map=new_to_old_atom_map,
old_chemical_state_key='A',
new_chemical_state_key='B')
return ligand_topology_proposal, old_solvated_positions
@property
def complex_topology_proposal(self):
return self._complex_topology_proposal
@property
def complex_old_positions(self):
return self._complex_positions_old_solvated
@property
def complex_new_positions(self):
return self._complex_positions_new_solvated
@property
def solvent_topology_proposal(self):
return self._solvent_topology_proposal
@property
def solvent_old_positions(self):
return self._old_solvent_positions
@property
def solvent_new_positions(self):
return self._new_solvent_positions
def generate_vacuum_topology_proposal(current_mol_name="benzene", proposed_mol_name="toluene", forcefield_kwargs=None, system_generator_kwargs=None):
"""
Generate a test vacuum topology proposal, current positions, and new positions triplet from two IUPAC molecule names.
Constraints are added to the system by default. To override this, set ``forcefield_kwargs = None``.
Parameters
----------
current_mol_name : str, optional
name of the first molecule
proposed_mol_name : str, optional
name of the second molecule
forcefield_kwargs : dict, optional, default=None
Additional arguments to ForceField in addition to
'removeCMMotion': False, 'nonbondedMethod': app.NoCutoff
system_generator_kwargs : dict, optional, default=None
Dict passed onto SystemGenerator
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
"""
from openmoltools import forcefield_generators
from perses.tests.utils import createOEMolFromIUPAC, createSystemFromIUPAC, get_data_filename
gaff_filename = get_data_filename('data/gaff.xml')
default_forcefield_kwargs = {'removeCMMotion': False, 'nonbondedMethod': app.NoCutoff, 'constraints' : app.HBonds}
forcefield_kwargs = default_forcefield_kwargs.update(forcefield_kwargs) if (forcefield_kwargs is not None) else default_forcefield_kwargs
system_generator_kwargs = system_generator_kwargs if (system_generator_kwargs is not None) else dict()
system_generator = SystemGenerator([gaff_filename, 'amber99sbildn.xml', 'tip3p.xml'],
forcefield_kwargs=forcefield_kwargs,
**system_generator_kwargs)
old_oemol = createOEMolFromIUPAC(current_mol_name)
from openmoltools.forcefield_generators import generateTopologyFromOEMol
old_topology = generateTopologyFromOEMol(old_oemol)
old_positions = extractPositionsFromOEMOL(old_oemol)
old_smiles = oechem.OEMolToSmiles(old_oemol)
old_system = system_generator.build_system(old_topology)
new_oemol = createOEMolFromIUPAC(proposed_mol_name)
new_smiles = oechem.OEMolToSmiles(new_oemol)
geometry_engine = geometry.FFAllAngleGeometryEngine()
proposal_engine = SmallMoleculeSetProposalEngine(
[old_smiles, new_smiles], system_generator, residue_name=current_mol_name)
#generate topology proposal
topology_proposal = proposal_engine.propose(old_system, old_topology, current_mol=old_oemol, proposed_mol=new_oemol)
# show atom mapping
filename = str(current_mol_name)+str(proposed_mol_name)+'.pdf'
render_atom_mapping(filename, old_oemol, new_oemol, topology_proposal.new_to_old_atom_map)
#generate new positions with geometry engine
new_positions, _ = geometry_engine.propose(topology_proposal, old_positions, beta)
# DEBUG: Zero out bonds and angles for one system
#print('Zeroing bonds of old system')
#for force in topology_proposal.old_system.getForces():
# if force.__class__.__name__ == 'HarmonicAngleForce':
# for index in range(force.getNumAngles()):
# p1, p2, p3, angle, K = force.getAngleParameters(index)
# K *= 0.0
# force.setAngleParameters(index, p1, p2, p3, angle, K)
# if False and force.__class__.__name__ == 'HarmonicBondForce':
# for index in range(force.getNumBonds()):
# p1, p2, r0, K = force.getBondParameters(index)
# K *= 0.0
# force.setBondParameters(index, p1, p2, r0, K)
# DEBUG : Box vectors
#box_vectors = np.eye(3) * 100 * unit.nanometers
#topology_proposal.old_system.setDefaultPeriodicBoxVectors(box_vectors[0,:], box_vectors[1,:], box_vectors[2,:])
#topology_proposal.new_system.setDefaultPeriodicBoxVectors(box_vectors[0,:], box_vectors[1,:], box_vectors[2,:])
return topology_proposal, old_positions, new_positions
['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()
print(num_old_constraints)
def create_systems(topologies_dict, positions_dict, output_directory, project_prefix, solvate=True):
"""
Generate the systems ready for equilibrium simulations from a dictionary of topologies and positions
Parameters
----------
topologies_dict : dict of str: app.Topoology
A dictionary of the topologies to prepare, indexed by SMILES strings
positions_dict : dict of str: unit.Quantity array
A dictionary of positions for the corresponding topologies, indexed by SMILES strings
output_directory : str
Location of output files
project_prefix : str
What to prepend to the names of files for this run
solvate : bool, default True
Whether to solvate the systems
"""
barostat = openmm.MonteCarloBarostat(1.0*unit.atmosphere, temperature, 50)
system_generator = SystemGenerator(['amber14/protein.ff14SB.xml', 'gaff.xml', 'amber14/tip3p.xml', 'MCL1_ligands.xml'], barostat=barostat, forcefield_kwargs={'nonbondedMethod': app.PME,
'constraints': app.HBonds,
'hydrogenMass': 4 * unit.amus}, use_antechamber=False)
list_of_smiles = list(topologies_dict.keys())
initial_smiles = list_of_smiles[0]
initial_topology = topologies_dict[initial_smiles]
initial_positions = positions_dict[initial_smiles]
if solvate:
solvated_initial_positions, solvated_topology, solvated_system = solvate_system(initial_topology.to_openmm(), initial_positions, system_generator)
else:
solvated_initial_positions = initial_positions
solvated_topology = initial_topology
solvated_system = system_generator.build_system(solvated_topology)
md_topology = md.Topology.from_openmm(solvated_topology)
if solvate:
num_added = md_topology.n_residues - initial_topology.n_residues
if not os.path.exists(output_directory):
os.mkdir(output_directory)
np.save("{}/{}_{}_initial.npy".format(output_directory,project_prefix, 0), (solvated_initial_positions, md_topology, solvated_system, initial_smiles))
for i in tqdm.trange(1, len(list_of_smiles)):
smiles = list_of_smiles[i]
topology = topologies_dict[smiles]
positions = positions_dict[smiles]
if solvate:
solvated_positions, solvated_topology, solvated_system = solvate_system(topology.to_openmm(), positions, system_generator, padding=None, num_added=num_added)
else:
solvated_positions = initial_positions
solvated_topology = initial_topology
solvated_system = system_generator.build_system(solvated_topology)
np.save("{}/{}_{}_initial.npy".format(output_directory,project_prefix, i),
(solvated_positions, md.Topology.from_openmm(solvated_topology), solvated_system, smiles))