def don_water(donor, donor_hyds, acceptor, sp2_O_rp2, sp2_O_r2, sp2_O_theta,
sp3_O_rp2, sp3_O_r2, sp3_O_theta, sp3_O_phi, sp3_N_rp2, sp3_N_r2,
sp3_N_theta, sp3_N_upsilon, gen_rp2, gen_r2, gen_theta):
if hbond.verbose:
print("don_water")
if len(donor_hyds) > 0:
# hydrogens explicitly present, can immediately call don_theta_tau
return don_theta_tau(donor, donor_hyds, acceptor, sp2_O_rp2,
sp2_O_theta, sp3_O_rp2, sp3_O_theta, sp3_O_phi, sp3_N_rp2,
sp3_N_theta, sp3_N_upsilon, gen_rp2, gen_theta)
ap = acceptor._hb_coord
dp = donor._hb_coord
acc_type = acceptor.idatm_type
if acc_type not in type_info:
if hbond.verbose:
print("Unknown acceptor type failure")
return False
geom = type_info[acc_type].geometry
element = acceptor.element.name
if element == 'O' and geom == planar:
if hbond.verbose:
print("planar O")
sq = distance_squared(dp, ap)
if sq > sp2_O_r2:
if hbond.verbose:
print("dist criteria failed (%g > %g)" % (sqrt(sq), sqrt(sp2_O_r2)))
return False
elif element == 'O' and geom == tetrahedral or element == 'N' and geom == planar:
if hbond.verbose:
print("planar N or tet O")
sq = distance_squared(dp, ap)
if sq > sp3_O_r2:
if hbond.verbose:
print("dist criteria failed (%g > %g)" % (sqrt(sq), sqrt(sp3_O_r2)))
return False
elif element == 'N' and geom == tetrahedral:
if hbond.verbose:
print("tet N")
sq = distance_squared(dp, ap)
if sq > sp3_N_r2:
if hbond.verbose:
print("dist criteria failed (%g > %g)" % (sqrt(sq), sqrt(sp3_N_r2)))
return False
else:
if hbond.verbose:
print("generic acceptor")
sq = distance_squared(dp, ap)
if sq > gen_r2:
if hbond.verbose:
print("dist criteria failed (%g > %g)" % (sqrt(sq), sqrt(gen_r2)))
return False
if hbond.verbose:
print("dist criteria OK")
return don_theta_tau(donor, donor_hyds, acceptor, sp2_O_rp2,
sp2_O_theta, sp3_O_rp2, sp3_O_theta, sp3_O_phi, sp3_N_rp2,
sp3_N_theta, sp3_N_upsilon, gen_rp2, gen_theta, is_water=True)
def test_upsion_tau_acceptor(donor, donor_hyds, acceptor, r2, upsilon_low, upsilon_high,
theta, tau, tau_sym):
dc = donor._hb_coord
ac = acceptor._hb_coord
d2 = distance_squared(dc, ac)
if d2 > r2:
if hbond.verbose:
print("dist criteria failed (%g > %g)" % (sqrt(d2), sqrt(r2)))
return False
upsilon_high = 0 - upsilon_high
heavys = [a for a in donor.neighbors if a.element.number > 1]
if len(heavys) != 1:
raise AtomTypeError("upsilon tau donor (%s) not bonded to"
" exactly one heavy atom" % donor)
ang = angle(heavys[0]._hb_coord, dc, ac)
if ang < upsilon_low or ang > upsilon_high:
if hbond.verbose:
print("upsilon criteria failed (%g < %g or %g > %g)"
% (ang, upsilon_low, ang, upsilon_high))
return False
if hbond.verbose:
print("upsilon criteria OK (%g < %g < %g)" % (upsilon_low, ang, upsilon_high))
dp = dc
ap = ac
if not test_theta(dp, donor_hyds, ap, theta):
return False
return test_tau(tau, tau_sym, donor, dp, ap)
def _make_shared_data(session, protonation_models, in_isolation):
from chimerax.geometry import distance_squared
from chimerax.atom_search import AtomSearchTree
# since adaptive search tree is static, it will not include
# hydrogens added after this; they will have to be found by
# looking off their heavy atoms
global search_tree, _radii, _metals, ident_pos_models, _h_coloring, _solvent_atoms
_radii = {}
search_atoms = []
metal_atoms = []
# if we're adding hydrogens to unopen models, add those models to open models...
pm_set = set(protonation_models)
if in_isolation:
models = pm_set
else:
from chimerax.atomic import AtomicStructure
om_set = set(
[m for m in session.models if isinstance(m, AtomicStructure)])
models = om_set | pm_set
# consider only one copy of identically-positioned models...
ident_pos_models = {}
for pm in protonation_models:
for m in models:
if m == pm:
continue
if pm.num_atoms != m.num_atoms:
continue
for a1, a2 in zip(pm.atoms[:3], m.atoms[:3]):
if distance_squared(a1._addh_coord, a2._addh_coord) > 0.00001:
break
else:
ident_pos_models.setdefault(pm, set()).add(m)
for m in models:
if m not in ident_pos_models:
ident_pos_models[m] = set()
for a in m.atoms:
search_atoms.append(a)
_radii[a] = a.radius
if a.element.is_metal:
metal_atoms.append(a)
from chimerax.atomic import Atom
use_scene_coords = Atom._addh_coord == Atom.scene_coord
search_tree = AtomSearchTree(search_atoms,
sep_val=_tree_dist,
scene_coords=use_scene_coords)
_metals = AtomSearchTree(metal_atoms,
sep_val=max(_metal_dist, 1.0),
scene_coords=use_scene_coords)
from weakref import WeakKeyDictionary
_h_coloring = WeakKeyDictionary()
_solvent_atoms = WeakKeyDictionary()
def evaluate(self, pos):
sum = 0.0
n = 0
from chimerax.geometry import distance_squared
for coords in self._gather_coords(pos):
for i, crd1 in enumerate(coords):
for crd2 in coords[i + 1:]:
sum += distance_squared(crd1, crd2)
n += (len(coords) * (len(coords) - 1)) // 2
if n == 0:
return None
from math import sqrt
return sqrt(sum / n)
def don_generic(donor, donor_hyds, acceptor, sp2_O_rp2, sp3_O_rp2, sp3_N_rp2,
sp2_O_r2, sp3_O_r2, sp3_N_r2, gen_rp2, gen_r2, min_hyd_angle, min_bonded_angle):
if hbond.verbose:
print("don_generic")
dc = donor._hb_coord
ac = acceptor._hb_coord
acc_type = acceptor.idatm_type
if acc_type not in type_info:
return False
geom = type_info[acc_type].geometry
element = acceptor.element.name
if element == 'O' and geom == planar:
if hbond.verbose:
print("planar O")
r2 = sp2_O_r2
rp2 = sp2_O_rp2
elif element == 'O' and geom == tetrahedral or element == 'N' and geom == planar:
if hbond.verbose:
print("planar N or tet O")
r2 = sp3_O_r2
rp2 = sp3_O_rp2
elif element == 'N' and geom == tetrahedral:
if hbond.verbose:
print("tet N")
r2 = sp3_N_r2
rp2 = sp3_N_rp2
else:
if hbond.verbose:
print("generic acceptor")
if acceptor.element.name == "S":
r2 = sulphur_compensate(gen_r2)
min_bonded_angle = min_bonded_angle - 9
r2 = gen_r2
rp2 = gen_rp2
ap = acceptor._hb_coord
dp = donor._hb_coord
if len(donor_hyds) == 0:
d2 = distance_squared(dc, ac)
if d2 > r2:
if hbond.verbose:
print("dist criteria failed (%g > %g)" % (sqrt(d2), sqrt(r2)))
return False
else:
for hyd_pos in donor_hyds:
if distance_squared(hyd_pos, ap) < rp2:
break
else:
if hbond.verbose:
print("hyd dist criteria failed (all >= %g)" % (sqrt(rp2)))
return False
if hbond.verbose:
print("dist criteria OK")
for bonded in donor.neighbors:
if bonded.element.number <= 1:
continue
bp = bonded._hb_coord
ang = angle(bp, dp, ap)
if ang < min_bonded_angle:
if hbond.verbose:
print("bonded angle too sharp (%g < %g)" % (ang, min_bonded_angle))
return False
if len(donor_hyds) == 0:
if hbond.verbose:
print("No specific hydrogen positions; default accept")
return True
for hyd_pos in donor_hyds:
ang = angle(dp, hyd_pos, ap)
if ang >= min_hyd_angle:
if hbond.verbose:
print("hydrogen angle okay (%g >= %g)" % (ang, min_hyd_angle))
return True
if hbond.verbose:
print("hydrogen angle(s) too sharp (< %g)" % min_hyd_angle)
return False
def don_theta_tau(donor, donor_hyds, acceptor, sp2_O_rp2, sp2_O_theta, sp3_O_rp2, sp3_O_theta,
sp3_O_phi, sp3_N_rp2, sp3_N_theta, sp3_N_upsilon, gen_rp2, gen_theta, is_water=False):
# 'is_water' only for hydrogenless water
if hbond.verbose:
print("don_theta_tau")
if len(donor_hyds) == 0 and not is_water:
if hbond.verbose:
print("No hydrogens; default failure")
return False
ap = acceptor._hb_coord
dp = donor._hb_coord
acc_type = acceptor.idatm_type
if acc_type not in type_info:
if hbond.verbose:
print("Unknown acceptor type failure")
return False
geom = type_info[acc_type].geometry
element = acceptor.element.name
if element == 'O' and geom == planar:
if hbond.verbose:
print("planar O")
for hyd_pos in donor_hyds:
if distance_squared(hyd_pos, ap) <= sp2_O_rp2:
break
else:
if not is_water:
if hbond.verbose:
print("dist criteria failed (all > %g)"% sqrt(sp2_O_rp2))
return False
theta = sp2_O_theta
elif element == 'O' and geom == tetrahedral or element == 'N' and geom == planar:
if hbond.verbose:
print("planar N or tet O")
for hyd_pos in donor_hyds:
if distance_squared(hyd_pos, ap) <= sp3_O_rp2:
break
else:
if not is_water:
if hbond.verbose:
print("dist criteria failed (all > %g)" % sqrt(sp3_O_rp2))
return False
theta = sp3_O_theta
# only test phi for acceptors with two bonded atoms
if acceptor.num_bonds == 2:
if hbond.verbose:
print("testing donor phi")
bonded = acceptor.neighbors
phi_plane, base_pos = get_phi_plane_params(acceptor, bonded[0], bonded[1])
if not test_phi(donor._hb_coord, ap, base_pos, phi_plane, sp3_O_phi):
return False
elif element == 'N' and geom == tetrahedral:
if hbond.verbose:
print("tet N")
for hyd_pos in donor_hyds:
if distance_squared(hyd_pos, ap) <= sp3_N_rp2:
break
else:
if not is_water:
if hbond.verbose:
print("dist criteria failed (all > %g)" % sqrt(sp3_N_rp2))
return False
theta = sp3_N_theta
# test upsilon against lone pair directions
bonded_pos = []
for bonded in acceptor.neighbors:
bonded_pos.append(bonded._hb_coord)
lp_pos = bond_positions(ap, geom, 1.0, bonded_pos)
if len(lp_pos) > 0:
# fixed lone pair positions
for lp in bond_positions(ap, geom, 1.0, bonded_pos):
# invert position so that we are measuring angles correctly
ang = angle(dp, ap, ap - (lp - ap))
if ang > sp3_N_upsilon:
if hbond.verbose:
print("acceptor upsilon okay (%g > %g)" % (ang, sp3_N_upsilon))
break
else:
if hbond.verbose:
print("all acceptor upsilons failed (< %g)" % sp3_N_upsilon)
return False
# else: indefinite lone pair positions; default okay
else:
if hbond.verbose:
print("generic acceptor")
if acceptor.element.name == "S":
gen_rp2 = sulphur_compensate(gen_rp2)
for hyd_pos in donor_hyds:
if distance_squared(hyd_pos, ap) <= gen_rp2:
break
else:
if hbond.verbose:
print("dist criteria failed (all > %g)" % sqrt(gen_rp2))
return False
theta = gen_theta
if hbond.verbose:
print("dist criteria OK")
return test_theta(dp, donor_hyds, ap, theta)
def cmd_define_plane(session,
atoms,
*,
thickness=defaults["plane_thickness"],
padding=0.0,
color=None,
radius=None,
name="plane"):
"""Wrapper to be called by command line.
Use chimerax.axes_planes.plane for other programming applications.
"""
from chimerax.core.errors import UserError
from chimerax.atomic import AtomicStructure, concatenate, Structure
if atoms is None:
structures_atoms = [
m.atoms for m in session.models if isinstance(m, AtomicStructure)
]
if structures_atoms:
atoms = concatenate(structures_atoms)
else:
raise UserError("Atom specifier selects no atoms")
if len(atoms) < 3:
raise UserError("Must specify at least 3 atoms to define a plane")
structures = atoms.unique_structures
if len(structures) > 1:
crds = atoms.scene_coords
else:
crds = atoms.coords
from chimerax.geometry import Plane, distance_squared
plane = Plane(crds)
if radius is None:
max_sq_dist = None
origin = plane.origin
for crd in crds:
projected = plane.nearest(crd)
sq_dist = distance_squared(origin, projected)
if max_sq_dist is None or sq_dist > max_sq_dist:
max_sq_dist = sq_dist
from math import sqrt
radius = sqrt(max_sq_dist)
if color is None:
from chimerax.atomic.colors import element_color, predominant_color
color = predominant_color(atoms)
if color is None:
color = element_color(a.element.number)
else:
color = color.uint8x4()
plane_model = PlaneModel(session, name, plane, thickness, radius + padding,
color)
if len(structures) > 1:
session.models.add([plane_model])
else:
structures[0].add([plane_model])
session.logger.info("Plane %s' placed at %s with normal %s" %
(name, plane.origin, plane.normal))
return plane_model
def cmd_hbonds(session,
atoms,
intra_model=True,
inter_model=True,
relax=True,
dist_slop=rec_dist_slop,
angle_slop=rec_angle_slop,
two_colors=False,
restrict="any",
radius=AtomicStructure.default_hbond_radius,
save_file=None,
batch=False,
inter_submodel=False,
make_pseudobonds=True,
retain_current=False,
reveal=False,
naming_style=None,
log=False,
cache_DA=None,
color=AtomicStructure.default_hbond_color,
slop_color=BuiltinColors["dark orange"],
show_dist=False,
intra_res=True,
intra_mol=True,
dashes=None,
salt_only=False,
name="hydrogen bonds",
coordsets=True,
select=False):
"""Wrapper to be called by command line.
Use hbonds.find_hbonds for other programming applications.
"""
if atoms is None:
from chimerax.atomic import concatenate
structures_atoms = [
m.atoms for m in session.models if isinstance(m, AtomicStructure)
]
if structures_atoms:
atoms = concatenate(structures_atoms)
else:
atoms = Atoms()
from chimerax.core.errors import UserError
if not atoms and not batch:
raise UserError("Atom specifier selects no atoms")
bond_color = color
if restrict == "both":
donors = acceptors = atoms
structures = atoms.unique_structures
elif restrict in ["cross", "any"]:
donors = acceptors = None
if inter_model:
structures = [
m for m in session.models if isinstance(m, AtomicStructure)
]
else:
structures = atoms.unique_structures
else: # another Atoms collection
if not restrict and not batch:
raise UserError("'restrict' atom specifier selects no atoms")
combined = atoms | restrict
donors = acceptors = combined
structures = combined.unique_structures
if not relax:
dist_slop = angle_slop = 0.0
base_kw = {
'inter_model': inter_model,
'intra_model': intra_model,
'donors': donors,
'acceptors': acceptors,
'inter_submodel': inter_submodel,
'cache_da': cache_DA
}
doing_coordsets = coordsets and len(
structures) == 1 and structures[0].num_coordsets > 1
if doing_coordsets:
hb_func = find_coordset_hbonds
struct_info = structures[0]
else:
hb_func = find_hbonds
struct_info = structures
result = hb_func(session,
struct_info,
dist_slop=dist_slop,
angle_slop=angle_slop,
**base_kw)
if doing_coordsets:
hb_lists = result
else:
hb_lists = [result]
for hbonds in hb_lists:
# filter on salt bridges first, since we need access to all H-bonds in order
# to assess which histidines should be considered salt-bridge donors
if salt_only:
sb_donors, sb_acceptors = salt_preprocess(hbonds)
hbonds[:] = [
hb for hb in hbonds
if hb[0] in sb_donors and hb[1] in sb_acceptors
]
hbonds[:] = restrict_hbonds(hbonds, atoms, restrict)
if not intra_mol:
mol_num = 0
mol_map = {}
for s in structures:
for m in s.molecules:
mol_num += 1
for a in m:
mol_map[a] = mol_num
hbonds[:] = [
hb for hb in hbonds if mol_map[hb[0]] != mol_map[hb[1]]
]
if not intra_res:
hbonds[:] = [hb for hb in hbonds if hb[0].residue != hb[1].residue]
if doing_coordsets:
cs_ids = structures[0].coordset_ids
output_info = (inter_model, intra_model, relax, dist_slop, angle_slop,
structures, hb_lists, cs_ids)
else:
output_info = (inter_model, intra_model, relax, dist_slop, angle_slop,
structures, result, None)
if log:
import io
buffer = io.StringIO()
buffer.write("<pre>")
_file_output(buffer, output_info, naming_style)
buffer.write("</pre>")
session.logger.info(buffer.getvalue(), is_html=True)
if save_file is not None:
_file_output(save_file, output_info, naming_style)
if doing_coordsets:
session.logger.status("%d hydrogen bonds found in %d coordsets" %
(sum([len(hbs)
for hbs in hb_lists]), len(cs_ids)),
log=True,
blank_after=120)
else:
session.logger.status("%d hydrogen bonds found" % len(result),
log=True,
blank_after=120)
if select:
if doing_coordsets:
structure = structures[0]
for i, cs_id in enumerate(structure.coordset_ids):
if structure.active_coordset_id == cs_id:
break
hb_list = hb_lists[i]
else:
hb_list = hb_lists[0]
cs_id = None
session.selection.clear()
for d, a in hb_list:
if cs_id is None:
acc_coord = a.scene_coord
else:
acc_coord = a.get_coordset_coord(cs_id)
dist, hyd = donor_hyd(d, cs_id, acc_coord)
if hyd is None:
d.selected = True
else:
hyd.selected = True
a.selected = True
if not make_pseudobonds:
return hb_lists if doing_coordsets else hb_lists[0]
if two_colors:
# color relaxed constraints differently
precise_result = hb_func(session, struct_info, **base_kw)
if doing_coordsets:
precise_lists = precise_result
else:
precise_lists = [precise_result]
for precise in precise_lists:
precise[:] = restrict_hbonds(precise, atoms, restrict)
if not intra_mol:
precise[:] = [
hb for hb in precise if mol_map[hb[0]] != mol_map[hb[1]]
]
if not intra_res:
precise[:] = [
hb for hb in precise if hb[0].residue != hb[1].residue
]
if salt_only:
precise[:] = [
hb for hb in precise
if hb[0] in sb_donors and hb[1] in sb_acceptors
]
# give another opportunity to read the result...
if doing_coordsets:
session.logger.status(
"%d strict hydrogen bonds found in %d coordsets" %
(sum([len(hbs) for hbs in precise_lists]), len(cs_ids)),
log=True,
blank_after=120)
else:
session.logger.status("%d strict hydrogen bonds found" %
len(precise_result),
log=True,
blank_after=120)
# a true inter-model computation should be placed in a global group, otherwise
# into individual per-structure groups
submodels = False
m_ids = set()
for s in structures:
m_id = s.id[:-1] if len(s.id) > 1 else s.id
if m_id in m_ids:
submodels = True
m_ids.add(m_id)
global_comp = (inter_model and len(m_ids) > 1) or (submodels
and inter_submodel)
if global_comp:
# global comp nukes per-structure groups it covers if intra-model also
if intra_model and not retain_current:
closures = []
for s in structures:
pbg = s.pseudobond_group(name, create_type=None)
if pbg:
closures.append(pbg)
if closures:
session.models.close(closures)
hb_info = [(result, session.pb_manager.get_group(name))]
elif doing_coordsets:
hb_info = [(result,
structures[0].pseudobond_group(name,
create_type="coordset"))]
else:
per_structure = {s: [] for s in structures}
for hb in result:
per_structure[hb[0].structure].append(hb)
hb_info = [(hbs, s.pseudobond_group(name, create_type="coordset"))
for s, hbs in per_structure.items()]
for grp_hbonds, pbg in hb_info:
if not retain_current:
pbg.clear()
pbg.color = bond_color.uint8x4()
pbg.radius = radius
pbg.dashes = dashes if dashes is not None else AtomicStructure.default_hbond_dashes
else:
if dashes is not None:
pbg.dashes = dashes
if not doing_coordsets:
grp_hbonds = [grp_hbonds]
for i, cs_hbonds in enumerate(grp_hbonds):
pre_existing = {}
if doing_coordsets:
cs_id = cs_ids[i]
pbg_pseudobonds = pbg.get_pseudobonds(cs_id)
else:
pbg_pseudobonds = pbg.pseudobonds
if two_colors:
precise = set(precise_lists[i])
if retain_current:
for pb in pbg_pseudobonds:
pre_existing[pb.atoms] = pb
from chimerax.geometry import distance_squared
for don, acc in cs_hbonds:
nearest = None
heavy_don = don
for h in [x for x in don.neighbors if x.element.number == 1]:
sqdist = distance_squared(h.scene_coord, acc.scene_coord)
if nearest is None or sqdist < nsqdist:
nearest = h
nsqdist = sqdist
if nearest is not None:
don = nearest
if (don, acc) in pre_existing:
pb = pre_existing[(don, acc)]
else:
if doing_coordsets:
pb = pbg.new_pseudobond(don, acc, cs_id)
else:
pb = pbg.new_pseudobond(don, acc)
if two_colors:
if (heavy_don, acc) in precise:
color = bond_color
else:
color = slop_color
else:
color = bond_color
rgba = pb.color
rgba[:3] = color.uint8x4()[:3] # preserve transparency
pb.color = rgba
pb.radius = radius
if reveal:
for end in [don, acc]:
if end.display:
continue
res_atoms = end.residue.atoms
if end.is_side_chain:
res_atoms.filter(res_atoms.is_side_chains ==
True).displays = True
elif end.is_backbone():
res_atoms.filter(res_atoms.is_backbones() ==
True).displays = True
else:
res_atoms.displays = True
if pbg.id is None:
session.models.add([pbg])
if show_dist:
session.pb_dist_monitor.add_group(pbg)
else:
session.pb_dist_monitor.remove_group(pbg)
return hb_lists if doing_coordsets else hb_lists[0]
def _alt_loc_add_hydrogens(atom, alt_loc_atom, bonding_info, naming_schema,
total_hydrogens, idatm_type, invert, coordinations):
from .cmd import new_hydrogen, find_nearest, roomiest, find_rotamer_nearest, add_altloc_hyds
from .util import bond_with_H_length
away = away2 = planar = None
geom = bonding_info.geometry
substs = bonding_info.substituents
needed = substs - atom.num_explicit_bonds
if needed <= 0:
return
added = None
if alt_loc_atom is None:
alt_locs = [atom.alt_loc]
else:
alt_locs = alt_loc_atom.alt_locs
# move current alt_loc to end of list to minimize
# the number of times we have to change alt locs
cur_alt_loc = alt_loc_atom.alt_loc
alt_locs.remove(cur_alt_loc)
alt_locs.append(cur_alt_loc)
alt_loc_info = []
for alt_loc in alt_locs:
if alt_loc_atom:
alt_loc_atom.alt_loc = alt_loc
occupancy = alt_loc_atom.occupancy
else:
occupancy = 1.0
at_pos = atom._addh_coord
exclude = coordinations + list(atom.neighbors)
if geom == 3:
if atom.num_bonds == 1:
bonded = atom.neighbors[0]
grand_bonded = list(bonded.neighbors)
grand_bonded.remove(atom)
if len(grand_bonded) < 3:
planar = [a._addh_coord for a in grand_bonded]
if geom == 4 and atom.num_bonds == 0:
away, d, natom = find_nearest(at_pos, atom, exclude, 3.5)
if away is not None:
away2, d2, natom2 = find_rotamer_nearest(
at_pos, idatm_type[atom], atom, natom, 3.5)
elif geom == 4 and len(coordinations) + atom.num_bonds == 1:
away, d, natom = find_rotamer_nearest(
at_pos, idatm_type[atom], atom,
(list(atom.neighbors) + coordinations)[0], 3.5)
else:
away, d, natom = find_nearest(at_pos, atom, exclude, 3.5)
bonded_pos = []
for bonded in atom.neighbors:
bonded_pos.append(bonded._addh_coord)
if coordinations:
toward = coordinations[0]._addh_coord
away2 = away
away = None
else:
toward = None
from chimerax.atomic.bond_geom import bond_positions
from chimerax.geometry import distance_squared
positions = bond_positions(at_pos,
geom,
bond_with_H_length(atom, geom),
bonded_pos,
toward=toward,
coplanar=planar,
away=away,
away2=away2)
if coordinations:
coord_pos = None
for pos in positions:
d = distance_squared(pos, toward)
if coord_pos is None or d < lowest:
coord_pos = pos
lowest = d
positions.remove(coord_pos)
if len(positions) > needed:
positions = roomiest(positions, atom, 3.5, bonding_info)[:needed]
alt_loc_info.append((alt_loc, occupancy, positions))
# delay adding Hs until all positions computed so that neighbors, etc. correct
# for later alt locs
add_altloc_hyds(atom, alt_loc_info, invert, bonding_info, total_hydrogens,
naming_schema)
def make_ladder(nd, residues, params):
"""generate links between residues that are hydrogen bonded together"""
# returns set of residues whose bases are drawn as rungs and
# and have their atoms hidden
all_shapes = []
# Create list of atoms from residues for donors and acceptors
mol = residues[0].structure
# make a set for quick inclusion test
residue_set = set(residues)
pbg = mol.pseudobond_group(mol.PBG_HYDROGEN_BONDS, create_type=None)
if not pbg:
bonds = ()
else:
bonds = (p.atoms for p in pbg.pseudobonds)
# only make one rung between residues even if there is more than one
# h-bond
depict_bonds = {}
for a0, a1 in bonds:
r0 = a0.residue
r1 = a1.residue
if r0 not in residue_set or r1 not in residue_set:
continue
non_base = (BackboneRiboseRE.match(a0.name),
BackboneRiboseRE.match(a1.name))
if params.skip_nonbase_Hbonds and any(non_base):
continue
if r0.connects_to(r1):
# skip covalently bonded residues
continue
if r1 < r0:
r0, r1 = r1, r0
non_base = (non_base[1], non_base[0])
c3p0 = _c3pos(r0)
if not c3p0:
continue
c3p1 = _c3pos(r1)
if not c3p1:
continue
if params.rung_radius and not any(non_base):
radius = params.rung_radius
# elif r0.ribbon_display and r1.ribbon_display:
# mgr = mol.ribbon_xs_mgr
# radius = min(mgr.scale_nucleic)
else:
# TODO: radius = a0.structure.stickScale \
# * chimera.Molecule.DefaultBondRadius
radius = a0.structure.bond_radius
key = (r0, r1)
if key in depict_bonds:
prev_radius = depict_bonds[key][2]
if prev_radius >= radius:
continue
depict_bonds[key] = (c3p0, c3p1, radius, non_base)
matched_residues = set()
if not params.stubs_only:
for (r0, r1), (c3p0, c3p1, radius, non_base) in depict_bonds.items():
a0 = r0.find_atom("C2")
a1 = r1.find_atom("C2")
r0color = r0.ring_color
r1color = r1.ring_color
# choose mid-point to make purine larger
try:
is_purine0 = standard_bases[nucleic3to1(
r0.name)]['tag'] == PURINE
is_purine1 = standard_bases[nucleic3to1(
r1.name)]['tag'] == PURINE
except KeyError:
is_purine0 = False
is_purine1 = False
if any(non_base) or is_purine0 == is_purine1:
mid = 0.5
elif is_purine0:
mid = purine_pyrimidine_ratio
else:
mid = 1.0 - purine_pyrimidine_ratio
midpt = c3p0[1] + mid * (c3p1[1] - c3p0[1])
va, na, ta = get_cylinder(radius, c3p0[1], midpt, top=False)
all_shapes.append(
AtomicShapeInfo(va, na, ta, r0color, r0.atoms, str(r0)))
va, na, ta = get_cylinder(radius, c3p1[1], midpt, top=False)
all_shapes.append(
AtomicShapeInfo(va, na, ta, r1color, r1.atoms, str(r1)))
if not non_base[0]:
matched_residues.add(r0)
if not non_base[1]:
matched_residues.add(r1)
if not params.show_stubs:
if params.hide:
return all_shapes, matched_residues
return all_shapes, ()
# draw stubs for unmatched nucleotide residues
for r in residues:
if r in matched_residues:
continue
c3p = _c3pos(r)
if not c3p:
continue
ep0 = c3p[1]
a = r.find_atom("C2")
color = r.ring_color
ep1 = None
name = nucleic3to1(r.name)
if name not in standard_bases:
continue
is_purine = standard_bases[name]['tag'] == PURINE
if is_purine:
a = r.find_atom('N1')
if a:
ep1 = a.coord
else:
# pyrimidine
a = r.find_atom('N3')
if a:
ep1 = a.coord
if ep1 is None:
# find farthest atom from C3'
dist_atom = (0, None)
for a in r.atoms:
dist = distance_squared(ep0, a.coord)
if dist > dist_atom[0]:
dist_atom = (dist, a)
ep1 = dist_atom[1].coord
va, na, ta = get_cylinder(params.rung_radius, ep0, ep1)
all_shapes.append(AtomicShapeInfo(va, na, ta, color, r.atoms, str(r)))
# make exposed end rounded (TODO: use a hemisphere)
va, na, ta = get_sphere(params.rung_radius, ep1)
all_shapes.append(AtomicShapeInfo(va, na, ta, color, r.atoms, str(r)))
matched_residues.add(r)
if params.hide:
return all_shapes, matched_residues
return all_shapes, ()
