data_comp_list
loop_
_chem_comp.id
_chem_comp.three_letter_code
_chem_comp.name
_chem_comp.group
_chem_comp.number_atoms_all
_chem_comp.number_atoms_nh
_chem_comp.desc_level
_chem_comp.initial_date
_chem_comp.modified_date
_chem_comp.source
 OEX  OEC  'OXYGEN EVOLVING SYSTEM              '  non-polymer  9  9  .  2013-09-13  2013-09-13
;
  Geometry restraints for OEX (Mn4CaO5 cluster in Photosystem II)
  Bond distances based on EXAFS experiments.  Angles are just guesses; the
  real structure should not be this box-like, but we don't have good data
  at high resolution that isn't radiation-damaged.  There is a separate CIF
  for the XRD-derived restraints based on 3arc, but I don't trust those angles.
  Derived from CCP4 monomer library entry for OEX; the coordinates listed
  here are from the original file, and are probably not reliable!
  Note that only 3arc (so far) contains this residue, due to errors
  in an earlier PSII structure which resulted in the chemical component
  dictionary for "OEX" ending up with one fewer oxygen.  However, all
  PSII complexes do in fact contain the entity described here.
  The EXAFS experiments indicate that 2-3 Mn-Ca distances are 3.4A, and
  1-2 distances are 3.9A.  I am assuming here that there are 3 of the first
  and 1 of the latter, since this is closest to the high-resolution SR
  structure (3arc), but it may be wise to try the other way too.
  Neutron distances added
;

data_comp_OEX
loop_
_chem_comp_atom.comp_id
_chem_comp_atom.atom_id
_chem_comp_atom.type_symbol
_chem_comp_atom.type_energy
_chem_comp_atom.partial_charge
_chem_comp_atom.x
_chem_comp_atom.y
_chem_comp_atom.z
 OEX  CA1  CA  CA  0.000   0.000   0.000  0.000
 OEX  O1   O   O   0.000   0.571  -2.042  0.959
 OEX  O2   O   O   0.000  -1.692  -0.358  1.784
 OEX  O3   O   O   0.000   0.203  -1.678  3.555
 OEX  O4   O   O   0.000  -1.730   2.012  2.935
 OEX  O5   O   O   0.000   1.205   0.665  2.078
 OEX  MN1  MN  MN  0.000   1.647  -1.867  2.479
 OEX  MN2  MN  MN  0.000  -1.121  -2.390  2.084
 OEX  MN3  MN  MN  0.000  -0.771   0.196  3.317
 OEX  MN4  MN  MN  0.000   0.119   2.891  2.443

loop_
_chem_comp_bond.comp_id
_chem_comp_bond.atom_id_1
_chem_comp_bond.atom_id_2
_chem_comp_bond.type
_chem_comp_bond.value_dist
_chem_comp_bond.value_dist_esd
_chem_comp_bond.value_dist_neutron
 OEX  MN1  O1   single  1.870  0.030  1.870
 OEX  MN1  O3   single  1.870  0.030  1.870
 OEX  MN1  O5   single  1.870  0.030  1.870
 OEX  MN2  O1   single  1.870  0.030  1.870
 OEX  MN2  O2   single  1.870  0.030  1.870
 OEX  MN2  O3   single  1.870  0.030  1.870
 OEX  MN3  O2   single  1.870  0.030  1.870
 OEX  MN3  O3   single  1.870  0.030  1.870
 OEX  MN3  O4   single  1.870  0.030  1.870
 OEX  MN3  O5   single  1.870  0.030  1.870
 OEX  MN4  O4   single  1.870  0.030  1.870
 OEX  MN4  O5   single  1.870  0.030  1.870
 OEX  MN1  MN2  single  2.750  0.050  2.750
 OEX  MN1  MN3  single  2.750  0.050  2.750
 OEX  MN2  MN3  single  3.300  0.050  3.300
 OEX  MN3  MN4  single  2.750  0.050  2.750
 OEX  CA1  MN1  single  3.400  0.050  3.400
 OEX  CA1  MN2  single  3.400  0.050  3.400
 OEX  CA1  MN3  single  3.400  0.050  3.400
 OEX  CA1  MN4  single  3.900  0.050  3.900

loop_
_chem_comp_angle.comp_id
_chem_comp_angle.atom_id_1
_chem_comp_angle.atom_id_2
_chem_comp_angle.atom_id_3
_chem_comp_angle.value_angle
_chem_comp_angle.value_angle_esd
 OEC  MN1  O1   MN2   90.000  1.000
 OEC  MN1  O3   MN2   90.000  1.000
 OEC  MN1  O5   MN3   90.000  1.000
 OEC  MN1  O3   MN3   90.000  1.000
 OEC  MN2  O2   MN3   90.000  1.000
 OEC  MN2  O3   MN3   90.000  1.000
 OEC  MN3  O4   MN4   90.000  1.000
 OEC  MN3  O5   MN4   90.000  1.000
 OEC  O1   MN1  O5    90.000  1.000
 OEC  O2   MN2  O1    90.000  1.000
 OEC  O2   MN3  O3    90.000  1.000
 OEC  MN1  O5   MN4  180.000  2.000
 OEC  O3   MN3  O4   180.000  2.000
 OEC  O2   MN3  O4    90.000  2.000
