def _add_dodecane_to_topology(self, topology):
# Carbon element
carbon_element = Element.getBySymbol('C')
hydrogen_element = Element.getBySymbol('H')
chain = topology.addChain("{}-C12".format(topology.getNumChains() + 1))
residue = topology.addResidue("C12", chain)
prev_atom = topology.addAtom("C", carbon_element, residue)
if self.forceField_str == "TraPPE-UA":
for i in range(11):
curr_atom = topology.addAtom("C{}".format(i + 1),
carbon_element, residue)
topology.addBond(prev_atom, curr_atom)
prev_atom = curr_atom
else:
H_counter = 0
for _ in range(3):
H = topology.addAtom("H{}".format(H_counter), hydrogen_element,
residue)
topology.addBond(H, prev_atom)
for i in range(11):
curr_atom = topology.addAtom("C{}".format(i + 1),
carbon_element, residue)
topology.addBond(prev_atom, curr_atom)
for _ in range(2):
H = topology.addAtom("H{}".format(H_counter),
hydrogen_element, residue)
topology.addBond(H, curr_atom)
prev_atom = curr_atom
H = topology.addAtom("H{}".format(H_counter), hydrogen_element,
residue)
topology.addBond(H, prev_atom)
return chain.id
def openmm_topology(atoms, bonds):
'''Make OpenMM topology from ChimeraX atoms and bonds.'''
a = atoms
n = len(a)
r = a.residues
aname = a.names
ename = a.element_names
rname = r.names
rnum = r.numbers
cids = r.chain_ids
from simtk.openmm.app import Topology, Element
top = Topology()
cmap = {}
rmap = {}
atoms = {}
for i in range(n):
cid = cids[i]
if not cid in cmap:
cmap[cid] = top.addChain() # OpenMM chains have no name.
rid = (rname[i], rnum[i], cid)
if not rid in rmap:
rmap[rid] = top.addResidue(rname[i], cmap[cid])
element = Element.getBySymbol(ename[i])
atoms[i] = top.addAtom(aname[i], element, rmap[rid])
a1, a2 = bonds.atoms
for i1, i2 in zip(a.indices(a1), a.indices(a2)):
top.addBond(atoms[i1], atoms[i2])
return top
def openmm_topology_from_chimerax_model(model):
'''
Take an AtomicStructure model from ChimeraX and return an OpenMM
topology (e.g. for use with the OpenMM Modeller class).
'''
a = model.atoms
b = model.bonds
n = len(a)
r = a.residues
aname = a.names
ename = a.element_names
rname = r.names
rnum = r.numbers
cids = r.chain_ids
from simtk.openmm.app import Topology, Element
from simtk import unit
top = Topology()
cmap = {}
rmap = {}
atoms = {}
for i in range(n):
cid = cids[i]
if not cid in cmap:
cmap[cid] = top.addChain() # OpenMM chains have no name
rid = (rname[i], rnum[i], cid)
if not rid in rmap:
rmap[rid] = top.addResidue(rname[i], cmap[cid])
element = Element.getBySymbol(ename[i])
atoms[i] = top.addAtom(aname[i], element, rmap[rid])
a1, a2 = b.atoms
for i1, i2 in zip(a.indices(a1), a.indices(a2)):
if -1 not in [i1, i2]:
top.addBond(atoms[i1], atoms[i2])
return top
def _apply_init(self, result: ComponentResult) -> None:
from simtk.openmm.app import Element
self._cache["elements"] = [
Element.getBySymbol(ele).atomic_number
if isinstance(ele, str) else ele for ele in self.allowed_elements
]
def _createTopology(self):
"""Build the topology of the system
"""
top = Topology()
positions = []
velocities = []
boxVectors = []
for x, y, z in self._conn.execute('SELECT x, y, z FROM global_cell'):
boxVectors.append(mm.Vec3(x, y, z))
unitCellDimensions = [boxVectors[0][0], boxVectors[1][1], boxVectors[2][2]]
top.setUnitCellDimensions(unitCellDimensions*angstrom)
atoms = {}
lastChain = None
lastResId = None
c = top.addChain()
q = """SELECT id, name, anum, resname, resid, chain, x, y, z, vx, vy, vz
FROM particle ORDER BY id"""
for (atomId, atomName, atomNumber, resName, resId, chain, x, y, z, vx, vy, vz) in self._conn.execute(q):
newChain = False
if chain != lastChain:
lastChain = chain
c = top.addChain()
newChain = True
if resId != lastResId or newChain:
lastResId = resId
if resName in PDBFile._residueNameReplacements:
resName = PDBFile._residueNameReplacements[resName]
r = top.addResidue(resName, c)
if resName in PDBFile._atomNameReplacements:
atomReplacements = PDBFile._atomNameReplacements[resName]
else:
atomReplacements = {}
if atomNumber == 0 and atomName.startswith('Vrt'):
elem = None
else:
elem = Element.getByAtomicNumber(atomNumber)
if atomName in atomReplacements:
atomName = atomReplacements[atomName]
atoms[atomId] = top.addAtom(atomName, elem, r)
positions.append(mm.Vec3(x, y, z))
velocities.append(mm.Vec3(vx, vy, vz))
for p0, p1 in self._conn.execute('SELECT p0, p1 FROM bond'):
top.addBond(atoms[p0], atoms[p1])
positions = positions*angstrom
velocities = velocities*angstrom/femtosecond
return top, positions, velocities
def _createTopology(self):
"""Build the topology of the system
"""
top = Topology()
positions = []
velocities = []
boxVectors = []
for x, y, z in self._conn.execute('SELECT x, y, z FROM global_cell'):
boxVectors.append(mm.Vec3(x, y, z))
unitCellDimensions = [boxVectors[0][0], boxVectors[1][1], boxVectors[2][2]]
top.setUnitCellDimensions(unitCellDimensions*angstrom)
atoms = {}
lastChain = None
lastResId = None
c = top.addChain()
q = """SELECT id, name, anum, resname, resid, chain, x, y, z, vx, vy, vz
FROM particle ORDER BY id"""
for (atomId, atomName, atomNumber, resName, resId, chain, x, y, z, vx, vy, vz) in self._conn.execute(q):
newChain = False
if chain != lastChain:
lastChain = chain
c = top.addChain()
newChain = True
if resId != lastResId or newChain:
lastResId = resId
if resName in PDBFile._residueNameReplacements:
resName = PDBFile._residueNameReplacements[resName]
r = top.addResidue(resName, c)
if resName in PDBFile._atomNameReplacements:
atomReplacements = PDBFile._atomNameReplacements[resName]
else:
atomReplacements = {}
if atomNumber == 0 and atomName.startswith('Vrt'):
elem = None
else:
elem = Element.getByAtomicNumber(atomNumber)
if atomName in atomReplacements:
atomName = atomReplacements[atomName]
atoms[atomId] = top.addAtom(atomName, elem, r)
positions.append(mm.Vec3(x, y, z))
velocities.append(mm.Vec3(vx, vy, vz))
for p0, p1 in self._conn.execute('SELECT p0, p1 FROM bond'):
top.addBond(atoms[p0], atoms[p1])
positions = positions*angstrom
velocities = velocities*angstrom/femtosecond
return top, positions, velocities
def openmm_topology_and_external_forces(self,
sim_construct,
sim_bonds,
fix_shell_backbones=False,
tug_hydrogens=False,
hydrogens_feel_maps=False,
logging=False,
log=None):
a = sim_construct
n = len(a)
r = a.residues
aname = a.names
ename = a.element_names
rname = r.names
rnum = r.numbers
cids = r.chain_ids
from simtk.openmm.app import Topology, Element
from simtk import unit
top = self._simulation_topology = Topology()
cmap = {}
rmap = {}
atoms = self._atoms = {}
for i in range(n):
cid = cids[i]
if not cid in cmap:
cmap[cid] = top.addChain() # OpenMM chains have no name
rid = (rname[i], rnum[i], cid)
if not rid in rmap:
rmap[rid] = top.addResidue(rname[i], cmap[cid])
element = Element.getBySymbol(ename[i])
atoms[i] = top.addAtom(aname[i], element, rmap[rid])
# Register atoms with forces
if ename is not 'H' or (ename is 'H' and tug_hydrogens):
# All CustomExternalForces
for key, ff in self._custom_external_forces.items():
f = ff[0]
per_particle_param_vals = ff[3]
index_map = ff[4]
index_map[i] = f.addParticle(i, per_particle_param_vals)
if ename is not 'H' or (ename is 'H' and hydrogens_feel_maps):
# All map forces
for m in self._maps:
self.couple_atom_to_map(i, m)
a1, a2 = sim_bonds.atoms
for i1, i2 in zip(a.indices(a1), a.indices(a2)):
if -1 not in [i1, i2]:
top.addBond(atoms[i1], atoms[i2])
from simtk.openmm import Vec3
pos = a.coords # in Angstrom (convert to nm for OpenMM)
return top, pos
def _createTopology(self):
'''Build the topology of the system
'''
top = Topology()
positions = []
boxVectors = []
for x, y, z in self._conn.execute('SELECT x, y, z FROM global_cell'):
boxVectors.append(mm.Vec3(x, y, z)*angstrom)
unitCellDimensions = [boxVectors[0][0], boxVectors[1][1], boxVectors[2][2]]
top.setUnitCellDimensions(unitCellDimensions)
atoms = {}
lastChain = None
lastResId = None
c = top.addChain()
q = '''SELECT id, name, anum, resname, resid, chain, x, y, z
FROM particle'''
for (atomId, atomName, atomNumber, resName, resId, chain, x, y, z) in self._conn.execute(q):
if chain != lastChain:
lastChain = chain
c = top.addChain()
if resId != lastResId:
lastResId = resId
if resName in PDBFile._residueNameReplacements:
resName = PDBFile._residueNameReplacements[resName]
r = top.addResidue(resName, c)
if resName in PDBFile._atomNameReplacements:
atomReplacements = PDBFile._atomNameReplacements[resName]
else:
atomReplacements = {}
if atomName in atomReplacements:
atomName = atomReplacements[atomName]
elem = Element.getByAtomicNumber(atomNumber)
atoms[atomId] = top.addAtom(atomName, elem, r)
positions.append(mm.Vec3(x, y, z)*angstrom)
for p0, p1 in self._conn.execute('SELECT p0, p1 FROM bond'):
top.addBond(atoms[p0], atoms[p1])
return top, positions
def check_allowed_elements(cls, element: Union[str,
int]) -> Union[str, int]:
"""
Check that each item can be cast to a valid element.
Parameters:
element: The element that should be checked.
Raises:
ValueError: If the element number or symbol passed could not be converted into a valid element.
"""
from simtk.openmm.app import Element
if isinstance(element, int):
return element
else:
try:
_ = Element.getBySymbol(element)
return element
except KeyError:
raise KeyError(
f"An element could not be determined from symbol {element}, please enter symbols only."
)
class BranchedChainOptions(ChainOptions):
_SECTION_NAME = "BranchedChain"
# =========================================================================
PHOSPHORUS = Element.getBySymbol('P')
# =========================================================================
def __init__(self, topology_options):
super(BranchedChainOptions, self).__init__(topology_options)
self.backbone = None
self.branches = []
self.pdb = None
def _create_options(self):
super(BranchedChainOptions, self)._create_options()
self._OPTIONS['backbone'] = self._parse_backbone
def _create_sections(self):
super(BranchedChainOptions, self)._create_sections()
self._SECTIONS['Branch'] = self._parse_branch
# =========================================================================
def _check_for_incomplete_input(self):
if self.backbone is None:
self._incomplete_error('backbone')
# =========================================================================
def _parse_backbone(self, *args):
self.backbone = evaluate_output(create_stack(tokenize_expr(args[0])))
def _parse_branch(self, *args):
line_deque = args[1]
branch_options = BranchOptions()
branch_options.parse(line_deque.popleft())
self.branches.append((branch_options.sequence, branch_options.indices))
# =========================================================================
def add_chain_to_topology(self, topology):
for _ in range(self.num):
self._add_chain(topology)
@staticmethod
def _find_atom_by_name(name, residue):
for atom in residue.atoms():
if atom.name == name:
return atom
raise ValueError("No atom with name {} found.".format(name))
def _add_chain(self, topology):
# create chain
chain = topology.addChain()
# determine residue adding function
if self.forceField_str == 'TraPPE-UA':
add_residue_function = self._add_residue_trappeua
elif self.forceField_str == 'OPLS-AA':
add_residue_function = self._add_residue_to_chain_oplsaa
else:
raise ValueError("Invalid force field.")
# initialize previous residue atom
prev_res_atom = None
# add backbone
for i, monomer in enumerate(self.backbone):
# determine whether or not the residue is a terminal one
left_ter = False
right_ter = False
if i == 0:
left_ter = True
if i == len(self.backbone) - 1:
right_ter = True
# add residue
prev_res_atom = add_residue_function(topology, chain,
prev_res_atom, monomer,
left_ter, right_ter)
# add branches
for sequence, indices in self.branches:
residues = list(chain.residues())
for index in indices:
atom = self._find_atom_by_name('C1', residues[index])
atom.element = self.PHOSPHORUS
prev_res_atom = atom
for i, monomer in enumerate(sequence):
right_ter = i == len(sequence) - 1
prev_res_atom = add_residue_function(topology,
chain,
prev_res_atom,
monomer,
right_ter=right_ter)
# create pdb file
if self.pdb is None:
positions = self._create_positions_trappeua()
topology_pdb = Topology()
topology_pdb._chains.append(chain)
bc_num = 0
dirname = os.path.join(os.path.dirname(__file__), "data")
while os.path.exists(
os.path.join(dirname,
"branched_chain_{}.pdb".format(bc_num))):
bc_num += 1
self.pdb = os.path.join(dirname,
"branched_chain_{}.pdb".format(bc_num))
PDBFile.writeFile(topology_pdb, positions, open(self.pdb, 'w'))
def _create_positions_trappeua(self):
positions = None
# load positions for mA12
mA12_pos = self._mA12_positions_trappeua()
# initialize list mapping residue number to atom index
res2atom = []
# number of atoms in each monomer type
Natoms_dict = {'A4': 9, 'A12': 17, 'mA12': 18}
# add backbone positions
for i, monomer in enumerate(self.backbone):
# add atom indices to res2atom
if res2atom:
res2atom.append(
np.arange(Natoms_dict[monomer]) + res2atom[-1][-1] + 1)
else:
res2atom.append(np.arange(Natoms_dict[monomer]))
# create monomer positions
pos = mA12_pos[:]
if monomer.startswith('A'):
pos = np.delete(pos, 2, axis=0)
if monomer.endswith('4'):
pos = pos[:-8]
# add monomer positions to chain positions
if positions is None:
positions = pos
else:
cos19 = np.cos(np.deg2rad(19.5))
cos30 = np.cos(np.deg2rad(30.0))
pos += 1.54 * np.array([cos19 * cos30, 0., 0.]) + np.array([
positions[res2atom[i - 1][1]][0], 0., 0.
]) - np.array([mA12_pos[0][0], 0., 0.])
positions = np.vstack((positions, pos))
# rotate methacrylate monomer positions
Rz = np.array([[0., 1., 0.], [-1., 0., 0.], [0., 0., 1.]])
mA12_pos_rot = mA12_pos.dot(Rz)
# add side chain positions
for sequence, indices in self.branches:
for res_index in indices:
prev_res_pos = positions[res2atom[res_index][1]]
for monomer in sequence:
# create monomer positions
pos = mA12_pos_rot[:] + np.array([
positions[res2atom[res_index][1]][0] -
mA12_pos_rot[1][0], 0., 0.
])
if monomer.startswith('A'):
pos = np.delete(pos, 2, axis=0)
if monomer.endswith('4'):
pos = pos[:-8]
# add monomer positions
cos19 = np.cos(np.deg2rad(19.5))
cos30 = np.cos(np.deg2rad(30.0))
pos += 1.54 * np.array([0., cos19 * cos30, 0.]) + np.array(
[0., prev_res_pos[1], 0.]) - np.array(
[0., pos[0][1], 0.])
positions = np.vstack((positions, pos))
prev_res_pos = pos[1]
return positions
@staticmethod
def _mA12_positions_trappeua():
# sines and cosines
sin19 = np.sin(np.deg2rad(19.5))
cos19 = np.cos(np.deg2rad(19.5))
sin30 = np.sin(np.deg2rad(30.0))
cos30 = np.cos(np.deg2rad(30.0))
sin54 = np.sin(np.deg2rad(54.75))
cos54 = np.cos(np.deg2rad(54.75))
# methacrylate positions
pos = 1.54 * np.array([cos19 * cos30, -cos19 * sin30, sin19])
pos = np.vstack(
(pos,
pos + 1.54 * np.array([cos19 * cos30, cos19 * sin30, -sin19])))
pos = np.vstack((pos, pos[1] + 1.54 * np.array([0., cos19, sin19])))
pos = np.vstack((pos, pos[1] + 1.52 * np.array([0., 0., -1.])))
pos = np.vstack((pos, pos[3] + 1.20 * np.array([0., cos30, -sin30])))
pos = np.vstack((pos, pos[3] + 1.344 * np.array([0., -cos30, -sin30])))
# C12 tail positions
for i in range(12):
if i == 0:
pos = np.vstack(
(pos, pos[-1] +
1.41 * np.array([0.0, (-1)**(i + 1) * cos54, -sin54])))
else:
pos = np.vstack(
(pos, pos[-1] +
1.54 * np.array([0.0, (-1)**(i + 1) * cos54, -sin54])))
return pos
def _add_residue_trappeua(self,
topology,
chain,
prev_res_atom,
monomer,
left_ter=False,
right_ter=False):
# determine monomer type
if monomer.startswith('mA'):
monomer_type = 'mA'
is_methyl = True
else:
monomer_type = 'A'
is_methyl = False
# determine chain length
end_chain_length = literal_eval(monomer.replace(monomer_type, ''))
# add residue to topology
residue = topology.addResidue(monomer, chain)
# add first two carbons
if left_ter and right_ter:
c_element = self.NITROGEN
c1_element = self.NITROGEN
elif left_ter:
c_element = self.BORON
c1_element = self.CARBON
elif right_ter:
c_element = self.NITROGEN
c1_element = self.CARBON
else:
c_element = self.CARBON
c1_element = self.CARBON
c = topology.addAtom('C', c_element, residue)
c1 = topology.addAtom('C1', c1_element, residue)
# add bond to previous residue if applicable
if prev_res_atom is not None:
topology.addBond(prev_res_atom, c)
# add bond between first two carbons
topology.addBond(c, c1)
# add methyl group if methacryalte
if is_methyl:
cm = topology.addAtom('Cm', self.CARBON, residue)
topology.addBond(c1, cm)
# add ester group atoms
c2 = topology.addAtom('C2', self.CARBON, residue)
topology.addBond(c1, c2)
oc = topology.addAtom('O', self.OXYGEN, residue)
topology.addBond(c2, oc)
oe = topology.addAtom('O1', self.OXYGEN, residue)
topology.addBond(c2, oe)
# add carbon chain
prev_atom = oe
for i in range(end_chain_length):
curr_atom = topology.addAtom('C{}'.format(i + 3), self.CARBON,
residue)
topology.addBond(prev_atom, curr_atom)
prev_atom = curr_atom
return c1
def _add_residue_oplsaa(self,
topology,
chain,
prev_res_atom,
monomer,
left_ter=False,
right_ter=False):
raise NotImplementedError(
"OPLS-AA not implemented for branched chain.")
class ChainOptions(_Options):
_SECTION_NAME = "Chain"
# =========================================================================
HYDROGEN = Element.getBySymbol('H')
BORON = Element.getBySymbol('B')
CARBON = Element.getBySymbol('C')
NITROGEN = Element.getBySymbol('N')
OXYGEN = Element.getBySymbol('O')
# =========================================================================
def __init__(self, topology_options):
super(ChainOptions, self).__init__()
self.topology_options = topology_options
self.forceField_str = topology_options.forceField_str
self.id = None
self.num = 1
self.sequence = None
self.create_pdb = True
self.overwrite_pdb = True
self.instructions = None
self.sequence_str = None
def _create_options(self):
super(ChainOptions, self)._create_options()
self._OPTIONS['id'] = self._parse_id
self._OPTIONS['num'] = self._parse_num
self._OPTIONS['sequence'] = self._parse_sequence
self._OPTIONS['createPDB'] = self._parse_create_pdb
self._OPTIONS['overwritePDB'] = self._parse_overwrite_pdb
self._OPTIONS['instructions'] = self._parse_instructions
# =========================================================================
def _check_for_incomplete_input(self):
if self.sequence is None:
self._incomplete_error('structure')
# =====================================================================[====
def _parse_id(self, *args):
self.id = args[0]
def _parse_num(self, *args):
self.num = literal_eval(args[0])
def _parse_sequence(self, *args):
structure_parser = _StructureParser(args[0])
self.sequence = structure_parser.get_chain_sequence()
self.sequence_str = str(structure_parser)
def _parse_create_pdb(self, *args):
self.create_pdb = literal_eval(args[0])
def _parse_overwrite_pdb(self, *args):
self.overwrite_pdb = literal_eval(args[0])
def _parse_instructions(self, *args):
self.instructions = [
instruction.strip() for instruction in args[0].split('/')
]
# =========================================================================
def add_chain_to_topology(self, topology):
# Map chain id to sequence
id_to_sequence = {}
# Add specified number of chains
for _ in range(self.num):
# Initialize topology and positions array for creating chain pdb
topology_pdb = Topology()
positions = []
# Determine chain pdb
if self.id is not None:
chain_id = "{}-{}".format(topology.getNumChains() + 1, self.id)
else:
chain_id = "{}-{}".format(topology.getNumChains() + 1,
self.sequence_str)
# Create chain
chain = topology.addChain(id=chain_id)
chain_pdb = topology_pdb.addChain(id=chain_id)
# Add chain id and sequence to dictionary
id_to_sequence[chain.id] = self.sequence_str
# Initialize atom from previous residue
prev_res_atom = None
prev_res_atom_pdb = None
# Initialize pos of atom on previous residue
prev_res_atom_pos = np.array([0.0, 0.0, 0.0])
# Iterate through sequence to add residues to chain
for j in range(len(self.sequence)):
# String representation of monomer
monomer = self.sequence[j]
# Determine whether or not the residue is a terminal one
left_ter = False
right_ter = False
if j == 0:
left_ter = True
if j == len(self.sequence) - 1:
right_ter = True
# Add residue to chain
if self.forceField_str == 'TraPPE-UA':
add_residue_function = self._add_residue_to_chain_trappeua
elif self.forceField_str == 'OPLS-AA':
add_residue_function = self._add_residue_to_chain_oplsaa
else:
raise ValueError("Invalid force field.")
prev_res_atom, prev_res_atom_pdb, prev_res_atom_pos = add_residue_function(
topology, topology_pdb, chain, chain_pdb, prev_res_atom,
prev_res_atom_pdb, positions, prev_res_atom_pos, monomer,
left_ter, right_ter)
# Create pdb file for chain
if self.create_pdb:
self._create_chain_pdb(topology_pdb, positions)
return id_to_sequence
def _add_residue_to_chain_oplsaa(self,
topology,
topology_pdb,
chain,
chain_pdb,
prev_res_atom,
prev_res_atom_pdb,
positions,
prev_res_atom_pos,
monomer,
left_ter=False,
right_ter=False):
# Determine monomer type
if monomer.startswith('mA'):
monomer_type = 'mA'
is_methyl = True
else:
monomer_type = 'A'
is_methyl = False
# Determine chain length
end_chain_length = literal_eval(monomer.replace(monomer_type, ''))
# Determine residue id
if left_ter:
residue_id = "LEFTTER"
elif right_ter:
residue_id = "RIGHTTER"
else:
residue_id = None
# Add residue to topology
residue = topology.addResidue(monomer, chain, id=residue_id)
residue_pdb = topology_pdb.addResidue(monomer,
chain_pdb,
id=residue_id)
# Function to add atoms to topology
def _add_atom_to_topology_oplsaa(name, element, counter):
# Add atom to topology
name = "{}{}".format(name, counter)
atom = topology.addAtom(name, element, residue)
atom_pdb = topology_pdb.addAtom(name, element, residue_pdb)
# Return atoms and position
return atom, atom_pdb, counter + 1
# Import positions from pdb
residue_positions = md.load(
os.path.join(self.topology_options.data_directory,
"mA12_aa.pdb")).xyz[0] * 10. + prev_res_atom_pos
residue_positions = list(residue_positions)
if end_chain_length < 12:
residue_positions = residue_positions[:-(12 - end_chain_length) *
3]
if not is_methyl:
residue_positions.pop(9)
residue_positions.pop(8)
residue_positions.pop(7)
if not right_ter or (left_ter and right_ter):
residue_positions.pop(5)
if (left_ter and right_ter) or (not left_ter):
residue_positions.pop(2)
positions += residue_positions
# Add first carbon and attached hydrogen atoms
C_counter = 0
H_counter = 0
C0, C0_pdb, C_counter = _add_atom_to_topology_oplsaa(
"C", self.CARBON, C_counter)
if left_ter and not right_ter:
num_H = 3
else:
num_H = 2
for _ in range(num_H):
H, H_pdb, H_counter = _add_atom_to_topology_oplsaa(
"H", self.HYDROGEN, H_counter)
self._add_bond_to_topology(H, H_pdb, C0, C0_pdb, topology,
topology_pdb)
# Add bond to previous residue if applicable
if prev_res_atom is not None:
self._add_bond_to_topology(C0, C0_pdb, prev_res_atom,
prev_res_atom_pdb, topology,
topology_pdb)
# Add second carbon
C1, C1_pdb, C_counter = _add_atom_to_topology_oplsaa(
"C", self.CARBON, C_counter)
self._add_bond_to_topology(C1, C1_pdb, C0, C0_pdb, topology,
topology_pdb)
if right_ter and not left_ter:
H, H_pdb, H_counter = _add_atom_to_topology_oplsaa(
"H", self.HYDROGEN, H_counter)
self._add_bond_to_topology(H, H_pdb, C1, C1_pdb, topology,
topology_pdb)
# Add methyl group or hydrogen if not methyl
if is_methyl:
Cm, Cm_pdb, C_counter = _add_atom_to_topology_oplsaa(
"C", self.CARBON, C_counter)
for _ in range(3):
H, H_pdb, H_counter = _add_atom_to_topology_oplsaa(
"H", self.HYDROGEN, H_counter)
self._add_bond_to_topology(H, H_pdb, Cm, Cm_pdb, topology,
topology_pdb)
self._add_bond_to_topology(Cm, Cm_pdb, C1, C1_pdb, topology,
topology_pdb)
else:
H, H_pdb, H_counter = _add_atom_to_topology_oplsaa(
"H", self.HYDROGEN, H_counter)
self._add_bond_to_topology(H, H_pdb, C1, C1_pdb, topology,
topology_pdb)
# Add carbonyl carbon
Cc, Cc_pdb, C_counter = _add_atom_to_topology_oplsaa(
"C", self.CARBON, C_counter)
self._add_bond_to_topology(Cc, Cc_pdb, C1, C1_pdb, topology,
topology_pdb)
# Add carbonyl oxygen
Oc, Oc_pdb, _, = _add_atom_to_topology_oplsaa("O", self.OXYGEN, 0)
self._add_bond_to_topology(Oc, Oc_pdb, Cc, Cc_pdb, topology,
topology_pdb)
# Add ether oxygen
Oe, Oe_pdb, _ = _add_atom_to_topology_oplsaa("O", self.OXYGEN, 1)
self._add_bond_to_topology(Oe, Oe_pdb, Cc, Cc_pdb, topology,
topology_pdb)
# Add alkyl chain
prev_atom = Oe
prev_atom_pdb = Oe_pdb
for _ in range(end_chain_length):
curr_atom, curr_atom_pdb, C_counter = _add_atom_to_topology_oplsaa(
"C", self.CARBON, C_counter)
for _ in range(2):
H, H_pdb, H_counter = _add_atom_to_topology_oplsaa(
"H", self.HYDROGEN, H_counter)
self._add_bond_to_topology(H, H_pdb, curr_atom, curr_atom_pdb,
topology, topology_pdb)
self._add_bond_to_topology(curr_atom, curr_atom_pdb, prev_atom,
prev_atom_pdb, topology, topology_pdb)
prev_atom = curr_atom
prev_atom_pdb = curr_atom_pdb
# Add hydrogen to last carbon
H, H_pdb, H_counter = _add_atom_to_topology_oplsaa(
"H", self.HYDROGEN, H_counter)
self._add_bond_to_topology(H, H_pdb, prev_atom, prev_atom_pdb,
topology, topology_pdb)
return C1, C1_pdb, prev_res_atom_pos + np.array([2.527, 0, 0])
def _add_residue_to_chain_trappeua(self,
topology,
topology_pdb,
chain,
chain_pdb,
prev_res_atom,
prev_res_atom_pdb,
positions,
prev_res_atom_pos,
monomer,
left_ter=False,
right_ter=False):
def _deg_to_rad(ang_deg):
return ang_deg * 2 * np.pi / 360.0
# Sines and cosines
sin19 = np.sin(_deg_to_rad(19.5))
cos19 = np.cos(_deg_to_rad(19.5))
sin30 = np.sin(_deg_to_rad(30.0))
cos30 = np.cos(_deg_to_rad(30.0))
sin54 = np.sin(_deg_to_rad(54.75))
cos54 = np.cos(_deg_to_rad(54.75))
# Determine monomer type
if monomer.startswith('mA'):
monomer_type = 'mA'
is_methyl = True
else:
monomer_type = 'A'
is_methyl = False
# Determine chain length
end_chain_length = literal_eval(monomer.replace(monomer_type, ''))
# Determine residue id
if left_ter:
residue_id = "LEFTTER"
elif right_ter:
residue_id = "RIGHTTER"
else:
residue_id = None
# Add residue to topology
residue = topology.addResidue(monomer, chain, id=residue_id)
residue_pdb = topology_pdb.addResidue(monomer,
chain_pdb,
id=residue_id)
# Add first two carbons
if left_ter and right_ter:
carbon_element = self.NITROGEN
carbon_1_element = self.NITROGEN
elif left_ter:
carbon_element = self.BORON
carbon_1_element = self.CARBON
elif right_ter:
carbon_element = self.NITROGEN
carbon_1_element = self.CARBON
else:
carbon_element = self.CARBON
carbon_1_element = self.CARBON
carbon_pos = prev_res_atom_pos + 1.54 * np.array(
[cos19 * cos30, -cos19 * sin30, sin19])
carbon, carbon_pdb = self._add_atom_to_topology_trappeua(
'C', carbon_element, residue, residue_pdb, topology, topology_pdb,
positions, carbon_pos)
carbon_1_pos = carbon_pos + 1.54 * np.array(
[cos19 * cos30, cos19 * sin30, -sin19])
carbon_1, carbon_1_pdb = self._add_atom_to_topology_trappeua(
'C1', carbon_1_element, residue, residue_pdb, topology,
topology_pdb, positions, carbon_1_pos)
# Add bond to previous residue if applicable
if prev_res_atom is not None:
self._add_bond_to_topology(carbon, carbon_pdb, prev_res_atom,
prev_res_atom_pdb, topology,
topology_pdb)
# Add bond between first two carbons
self._add_bond_to_topology(carbon, carbon_pdb, carbon_1, carbon_1_pdb,
topology, topology_pdb)
# Add methyl group if methacrylate monomer
if is_methyl:
carbon_methyl_pos = carbon_1_pos + 1.54 * np.array([0.0, 1.0, 0.0])
carbon_methyl, carbon_methyl_pdb = self._add_atom_to_topology_trappeua(
'Cm', self.CARBON, residue, residue_pdb, topology,
topology_pdb, positions, carbon_methyl_pos)
self._add_bond_to_topology(carbon_1, carbon_1_pdb, carbon_methyl,
carbon_methyl_pdb, topology,
topology_pdb)
# Add ester group atoms
carbon_2_pos = carbon_1_pos + 1.52 * np.array([0.0, 0.0, -1.0])
carbon_2, carbon_2_pdb = self._add_atom_to_topology_trappeua(
'C2', self.CARBON, residue, residue_pdb, topology, topology_pdb,
positions, carbon_2_pos)
self._add_bond_to_topology(carbon_1, carbon_1_pdb, carbon_2,
carbon_2_pdb, topology, topology_pdb)
oxygen_carbonyl_pos = carbon_2_pos + 1.20 * np.array(
[0.0, cos30, -sin30])
oxygen_carbonyl, oxygen_carbonyl_pdb = self._add_atom_to_topology_trappeua(
'O', self.OXYGEN, residue, residue_pdb, topology, topology_pdb,
positions, oxygen_carbonyl_pos)
self._add_bond_to_topology(carbon_2, carbon_2_pdb, oxygen_carbonyl,
oxygen_carbonyl_pdb, topology, topology_pdb)
oxygen_ether_pos = carbon_2_pos + 1.344 * np.array(
[0.0, -cos30, -sin30])
oxygen_ether, oxygen_ether_pdb = self._add_atom_to_topology_trappeua(
'O', self.OXYGEN, residue, residue_pdb, topology, topology_pdb,
positions, oxygen_ether_pos)
self._add_bond_to_topology(carbon_2, carbon_2_pdb, oxygen_ether,
oxygen_ether_pdb, topology, topology_pdb)
# Add carbon chain
prev_atom_pos = oxygen_ether_pos
prev_atom = oxygen_ether
prev_atom_pdb = oxygen_ether_pdb
for i in range(end_chain_length):
if i == 0:
curr_atom_pos = prev_atom_pos + 1.41 * np.array(
[0.0, (-1)**(i + 1) * cos54, -sin54])
else:
curr_atom_pos = prev_atom_pos + 1.54 * np.array(
[0.0, (-1)**(i + 1) * cos54, -sin54])
curr_atom, curr_atom_pdb = self._add_atom_to_topology_trappeua(
'C{}'.format(i + 3), self.CARBON, residue, residue_pdb,
topology, topology_pdb, positions, curr_atom_pos)
self._add_bond_to_topology(prev_atom, prev_atom_pdb, curr_atom,
curr_atom_pdb, topology, topology_pdb)
prev_atom_pos = curr_atom_pos
prev_atom = curr_atom
prev_atom_pdb = curr_atom_pdb
return carbon_1, carbon_1_pdb, carbon_1_pos
@staticmethod
def _add_atom_to_topology_trappeua(name, element, residue, residue_pdb,
topology, topology_pdb, positions,
atom_pos):
# Add atom to topology
atom = topology.addAtom(name, element, residue)
atom_pdb = topology_pdb.addAtom(name, element, residue_pdb)
# Add position to array
positions.append(atom_pos)
# Return atoms and position
return atom, atom_pdb
@staticmethod
def _add_bond_to_topology(atom1, atom1_pdb, atom2, atom2_pdb, topology,
topology_pdb):
topology.addBond(atom1, atom2)
topology_pdb.addBond(atom1_pdb, atom2_pdb)
def _create_chain_pdb(self, topology_pdb, positions):
dirname = os.path.dirname(__file__)
filename = "{}.pdb".format(self.sequence_str)
if self.forceField_str == 'OPLS-AA':
filename = "{}_aa.pdb".format(self.sequence_str)
file_path = os.path.join(dirname, "data/{}".format(filename))
if not os.path.isfile(file_path) or self.overwrite_pdb:
self.overwrite_pdb = False
PDBFile.writeFile(topology_pdb, positions, open(file_path, 'w'))
def _createTopology(self):
"""Build the topology of the system
"""
top = Topology()
positions = []
velocities = []
boxVectors = []
#assume cell dimensions are set in the first file
#the other molecules inherit the same cell
conn = self._conn[0]
self.pbc = False
if self._hasTable('global_cell', self._tables[0]):
for x, y, z in conn.execute('SELECT x, y, z FROM global_cell'):
boxVectors.append(mm.Vec3(x, y, z))
unitCellDimensions = [boxVectors[0][0], boxVectors[1][1], boxVectors[2][2]]
top.setUnitCellDimensions(unitCellDimensions*angstrom)
self.pbc = True
#process each file
nfiles = len(self._conn)
for (fcounter, conn, tables) in zip(range(0,nfiles),self._conn,self._tables):
"""
resdb = {}
chaindb = {}
"""
atoms = {}
lastChain = None
lastResId = None
c = top.addChain()
q = """SELECT id, name, anum, resname, resid, chain, x, y, z, vx, vy, vz
FROM particle ORDER BY id"""
for (atomId, atomName, atomNumber, resName, resId, chain, x, y, z, vx, vy, vz) in conn.execute(q):
"""
#more elegant way to assign atoms to residues
#but it works only if atoms in residues are contiguous
#due to the fact that openmm does not support non-contiguous residues
resuid = "%s:%s:%s" % (resName, resId, chain)
if resuid in resdb.keys():
r = resdb[resuid]
c = chaindb[chain]
else:
if chain in chaindb.keys():
c = chaindb[chain]
else:
c = top.addChain()
chaindb[chain] = c
r = top.addResidue(resName, c)
resdb[resuid] = r
"""
newChain = False
if chain != lastChain:
lastChain = chain
c = top.addChain()
newChain = True
if resId != lastResId or newChain:
lastResId = resId
if resName in PDBFile._residueNameReplacements:
resName = PDBFile._residueNameReplacements[resName]
r = top.addResidue(resName, c)
if resName in PDBFile._atomNameReplacements:
atomReplacements = PDBFile._atomNameReplacements[resName]
else:
atomReplacements = {}
if atomNumber == 0 and atomName.startswith('Vrt'):
elem = None
else:
elem = Element.getByAtomicNumber(atomNumber)
if atomName in atomReplacements:
atomName = atomReplacements[atomName]
atoms[atomId] = top.addAtom(atomName, elem, r)
positions.append(mm.Vec3(x, y, z))
velocities.append(mm.Vec3(vx, vy, vz))
self._natoms[fcounter] = len(atoms)
for p0, p1 in conn.execute('SELECT p0, p1 FROM bond'):
top.addBond(atoms[p0], atoms[p1])
positions = positions*angstrom
velocities = velocities*angstrom/picosecond
return top, positions, velocities
def _add_squalane_to_topology(self, topology):
# Carbon element
carbon_element = Element.getBySymbol('C')
hydrogen_element = Element.getBySymbol('H')
chain = topology.addChain(
"{}-squalane".format(topology.getNumChains() + 1))
residue = topology.addResidue("squalane", chain)
prev_atom = None
if self.forceField_str == "TraPPE-UA":
atom_index = 0
for _ in range(3):
C1 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
if prev_atom is not None:
topology.addBond(prev_atom, C1)
C2 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C1, C2)
C3 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C2, C3)
C4 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C2, C4)
C5 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C4, C5)
prev_atom = C5
for _ in range(3):
C1 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(prev_atom, C1)
C2 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C1, C2)
C3 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C2, C3)
C4 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C3, C4)
C5 = topology.addAtom("C{}".format(atom_index), carbon_element,
residue)
atom_index += 1
topology.addBond(C3, C5)
prev_atom = C5
else:
raise NotImplementedError("OPLS-AA not implemented for squalane")
return chain.id
