441 lines
16 KiB
Python
441 lines
16 KiB
Python
#
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# Container for molecular conformations
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#
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from __future__ import division
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import Source.group, Source.determinants, Source.determinant, Source.ligand, Source.output, Source.coupled_groups, functools
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class Conformation_container:
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def __init__(self, name='', parameters=None, molecular_container=None):
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self.molecular_container = molecular_container
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self.name=name
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self.parameters=parameters
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self.atoms = []
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self.groups = []
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self.chains = []
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self.current_iter_item = 0
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self.marvin_pkas_calculated = False
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self.non_covalently_coupled_groups = False
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return
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#
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# Group related methods
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#
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def extract_groups(self):
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""" Generates at list of molecular groups needed for calculating pKa values """
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for atom in self.get_non_hydrogen_atoms():
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# has this atom been checked for groups?
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if atom.groups_extracted == 0:
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self.validate_group(Source.group.is_group(self.parameters, atom))
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# if the atom has been checked in a another conformation, check if it has a
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# group that should be used in this conformation as well
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elif atom.group:
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self.validate_group(atom.group)
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return
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def additional_setup_when_reading_input_file(self):
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# if a group is coupled and we are reading a .propka_input file,
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# some more configuration might be needed
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# print coupling map
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map = Source.output.make_interaction_map('Covalent coupling map for %s'%self,
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self.get_covalently_coupled_groups(),
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lambda g1,g2: g1 in g2.covalently_coupled_groups)
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print(map)
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# check if we should set a common charge centre as well
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if self.parameters.common_charge_centre:
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self.set_common_charge_centres()
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return
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def set_common_charge_centres(self):
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for system in self.get_coupled_systems(self.get_covalently_coupled_groups(), Source.group.Group.get_covalently_coupled_groups):
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# make a list of the charge centre coordinates
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all_coordinates = list(map(lambda g: [g.x, g.y, g.z], system))
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# find the common charge center
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ccc = functools.reduce(lambda g1,g2: [g1[0]+g2[0], g1[1]+g2[1], g1[2]+g2[2]], all_coordinates)
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ccc = list(map(lambda c: c/len(system), ccc))
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# set the ccc for all coupled groups in this system
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for g in system:
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[g.x, g.y, g.z] = ccc
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g.common_charge_centre = True
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return
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def find_covalently_coupled_groups(self):
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""" Finds covalently coupled groups and sets common charge centres if needed """
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for group in [ group for group in self.groups if group.titratable]:
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# Find covalently bonded groups
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bonded_groups = self.find_bonded_titratable_groups(group.atom, 1, group.atom)
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# couple groups
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for cg in bonded_groups:
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if cg in group.covalently_coupled_groups:
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continue
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if cg.atom.sybyl_type == group.atom.sybyl_type:
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group.couple_covalently(cg)
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# check if we should set a common charge centre as well
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if self.parameters.common_charge_centre:
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self.set_common_charge_centres()
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# print coupling map
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map = Source.output.make_interaction_map('Covalent coupling map for %s'%self,
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#self.get_titratable_groups(),
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self.get_covalently_coupled_groups(),
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lambda g1,g2: g1 in g2.covalently_coupled_groups)
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print(map)
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return
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def find_non_covalently_coupled_groups(self, verbose=False):
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# check if non-covalent coupling has already been set up in an input file
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if len(list(filter(lambda g: len(g.non_covalently_coupled_groups)>0, self.get_titratable_groups())))>0:
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self.non_covalently_coupled_groups = True
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Source.coupled_groups.nccg.identify_non_covalently_coupled_groups(self,verbose=verbose)
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# re-do the check
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if len(list(filter(lambda g: len(g.non_covalently_coupled_groups)>0, self.get_titratable_groups())))>0:
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self.non_covalently_coupled_groups = True
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return
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def find_bonded_titratable_groups(self, atom, no_bonds, original_atom):
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res = set()
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for ba in atom.bonded_atoms:
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# skip the original atom
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if ba == original_atom:
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continue
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# check if this atom has a titratable group
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if ba.group and ba.group.titratable and no_bonds <= self.parameters.coupling_max_number_of_bonds:
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res.add(ba.group)
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# check for titratable groups bonded to this atom
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if no_bonds < self.parameters.coupling_max_number_of_bonds:
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res |= self.find_bonded_titratable_groups(ba,no_bonds+1, original_atom)
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return res
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def validate_group(self, group):
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""" Checks if we want to include this group in the calculations """
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# Is it recognized as a group at all?
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if not group:
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return
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# Other checks (include ligands, which chains etc.)
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# if all ok, accept the group
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self.accept_group(group)
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return
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def accept_group(self, group):
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# set up the group
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group.parameters=self.parameters
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group.setup()
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# and store it
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self.groups.append(group)
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return
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#
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# pka calculation methods
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#
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def calculate_pka(self, version, options):
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print('\nCalculating pKas for',self)
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# calculate desolvation
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for group in self.get_titratable_groups()+self.get_ions():
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version.calculate_desolvation(group)
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# calculate backbone interactions
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Source.determinants.setBackBoneDeterminants(self.get_titratable_groups(), self.get_backbone_groups(), version)
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# setting ion determinants
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Source.determinants.setIonDeterminants(self, version)
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# calculating the back-bone reorganization/desolvation term
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version.calculateBackBoneReorganization(self)
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# setting remaining non-iterative and iterative side-chain & Coulomb interaction determinants
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Source.determinants.setDeterminants(self.get_sidechain_groups(), version=version, options=options)
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# calculating the total pKa values
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for group in self.groups: group.calculate_total_pka()
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# take coupling effects into account
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penalised_labels = self.coupling_effects()
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if self.parameters.remove_penalised_group and len(penalised_labels)>0:
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print('Removing penalised groups!!!')
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for g in self.get_titratable_groups():
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g.remove_determinants(penalised_labels)
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# re-calculating the total pKa values
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for group in self.groups: group.calculate_total_pka()
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return
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def coupling_effects(self):
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#
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# Bases: The group with the highest pKa (the most stable one in the
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# charged form) will be the first one to adopt a proton as pH
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# is lowered and this group is allowed to titrate.
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# The remaining groups are penalised
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#
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# Acids: The group with the highest pKa (the least stable one in the
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# charged form) will be the last group to loose the proton as
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# pH is raised and will be penalised.
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# The remaining groups are allowed to titrate.
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#
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penalised_labels = []
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for all_groups in self.get_coupled_systems(self.get_covalently_coupled_groups(),
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Source.group.Group.get_covalently_coupled_groups):
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# check if we should share determinants
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if self.parameters.shared_determinants:
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self.share_determinants(all_groups)
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# find the group that has the highest pKa value
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first_group = max(all_groups, key=lambda g:g.pka_value)
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# In case of acids
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if first_group.charge < 0:
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first_group.coupled_titrating_group = min(all_groups, key=lambda g:g.pka_value)
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penalised_labels.append(first_group.label) # group with the highest pKa is penalised
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# In case of bases
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else:
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for a in all_groups:
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if a == first_group:
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continue # group with the highest pKa is allowed to titrate...
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a.coupled_titrating_group = first_group
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penalised_labels.append(a.label) #... and the rest is penalised
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return penalised_labels
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def share_determinants(self, groups):
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# make a list of the determinants to share
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types = ['sidechain','backbone','coulomb']
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for type in types:
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# find maximum value for each determinant
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max_dets = {}
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for g in groups:
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for d in g.determinants[type]:
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# update max dets
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if d.group not in max_dets.keys():
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max_dets[d.group] = d.value
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else:
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max_dets[d.group] = max(d.value, max_dets[d.group], key= lambda v: abs(v))
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# overwrite/add maximum value for each determinant
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for det_group in max_dets.keys():
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new_determinant = Source.determinant.Determinant(det_group, max_dets[det_group])
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for g in groups:
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g.set_determinant(new_determinant,type)
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return
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def get_coupled_systems(self, groups, get_coupled_groups):
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""" This generator will yield one covalently coupled system at the time """
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groups = set(groups)
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while len(groups)>0:
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# extract a system of coupled groups ...
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system = set()
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self.get_a_coupled_system_of_groups(groups.pop(), system, get_coupled_groups)
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# ... and remove them from the list
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groups -= system
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yield system
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return
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def get_a_coupled_system_of_groups(self, new_group, coupled_groups, get_coupled_groups):
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coupled_groups.add(new_group)
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[self.get_a_coupled_system_of_groups(c, coupled_groups, get_coupled_groups) for c in get_coupled_groups(new_group) if c not in coupled_groups]
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return
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#
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# Energy/summary-related methods
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#
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def calculate_folding_energy(self, pH=None, reference=None):
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ddg = 0.0
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for group in self.groups:
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#print('Folding energy for %s at pH %f: %f'%(group,pH,group.calculate_folding_energy(self.parameters, pH=pH, reference=reference)))
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ddg += group.calculate_folding_energy(self.parameters, pH=pH, reference=reference)
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return ddg
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def calculate_charge(self, parmaeters, pH=None):
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unfolded = folded = 0.0
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for group in self.get_titratable_groups():
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unfolded += group.calculate_charge(parmaeters, pH=pH, state='unfolded')
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folded += group.calculate_charge(parmaeters, pH=pH, state='folded')
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return unfolded,folded
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#
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# conformation/bookkeeping/atom methods
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#
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def get_backbone_groups(self):
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""" returns all backbone groups needed for the pKa calculations """
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return [group for group in self.groups if 'BB' in group.type]
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def get_sidechain_groups(self):
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""" returns all sidechain groups needed for the pKa calculations """
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return [group for group in self.groups if ('BB' not in group.type\
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and not group.atom.cysteine_bridge)]
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def get_covalently_coupled_groups(self):
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return [g for g in self.groups if len(g.covalently_coupled_groups)>0]
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def get_non_covalently_coupled_groups(self):
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return [g for g in self.groups if len(g.non_covalently_coupled_groups)>0]
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def get_backbone_NH_groups(self):
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""" returns all NH backbone groups needed for the pKa calculations """
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return [group for group in self.groups if group.type == 'BBN']
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def get_backbone_CO_groups(self):
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""" returns all CO backbone groups needed for the pKa calculations """
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return [group for group in self.groups if group.type == 'BBC']
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def get_groups_in_residue(self, residue):
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return [group for group in self.groups if group.residue_type == residue]
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def get_titratable_groups(self):
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return [group for group in self.groups if group.titratable]
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def get_titratable_groups_and_cysteine_bridges(self):
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return [group for group in self.groups if group.titratable or group.residue_type == 'CYS']
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def get_acids(self):
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return [group for group in self.groups if (group.residue_type in self.parameters.acid_list
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and not group.atom.cysteine_bridge)]
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def get_backbone_reorganisation_groups(self):
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return [group for group in self.groups if (group.residue_type in self.parameters.backbone_reorganisation_list
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and not group.atom.cysteine_bridge)]
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def get_ions(self):
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return [group for group in self.groups if group.residue_type in self.parameters.ions.keys()]
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def get_group_names(self, list):
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return [group for group in self.groups if group.type in list]
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def get_ligand_atoms(self):
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return [atom for atom in self.atoms if atom.type=='hetatm']
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def get_heavy_ligand_atoms(self):
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return [atom for atom in self.atoms if atom.type=='hetatm' and atom.element != 'H']
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def get_chain(self,chain):
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return [atom for atom in self.atoms if atom.chainID != chain]
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def add_atom(self, atom):
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#print(self,'adding',atom)
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self.atoms.append(atom)
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if not atom.conformation_container:
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atom.conformation_container = self
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if not atom.molecular_container:
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atom.molecular_container = self.molecular_container
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# store chain id for bookkeeping
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if not atom.chainID in self.chains:
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self.chains.append(atom.chainID)
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return
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def copy_atom(self, atom):
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new_atom = atom.makeCopy()
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self.atoms.append(new_atom)
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new_atom.conformation_container = self
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return
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def get_non_hydrogen_atoms(self):
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return [atom for atom in self.atoms if atom.element!='H']
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def top_up(self, other):
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""" Tops up self with all atoms found in other but not in self """
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for atom in other.atoms:
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if not self.have_atom(atom):
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self.copy_atom(atom)
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return
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def have_atom(self, atom):
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res = False
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for a in self.atoms:
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if a.residue_label == atom.residue_label:
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res = True
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break
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return res
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def find_group(self, group):
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for g in self.groups:
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if g.atom.residue_label == group.atom.residue_label:
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if g.type == group.type:
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return g
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return False
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def set_ligand_atom_names(self):
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for atom in self.get_ligand_atoms():
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Source.ligand.assign_sybyl_type(atom)
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return
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def __str__(self):
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return'Conformation container %s with %d atoms and %d groups'%(self.name,len(self),len(self.groups))
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def __len__(self):
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return len(self.atoms)
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def sort_atoms(self):
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# sort the atoms ...
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self.atoms.sort(key=self.sort_atoms_key)
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# ... and re-number them
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for i in range(len(self.atoms)):
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self.atoms[i].numb = i+1
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return
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def sort_atoms_key(self, atom):
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key = ord(atom.chainID)*1e7
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key += atom.resNumb*1000
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if len(atom.name) > len(atom.element):
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key += ord(atom.name[len(atom.element)])
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#print(atom,ord(atom.name[len(atom.element)]), '|%s||%s|'%(atom.name,atom.element))
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return key
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