[ccp4bb]: CO2-conformation

[jjm <jjm@mdc-berlin.de>]

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Dear all,
refining a high resolution structure with refmac5 we found a CO2 molecule.
Refmac5 dictionary knows CO2 but the molecule has an dihedral angle of 109 degr. and C-O distances of 1.41 A. The HIC-Up server comes up with a linear
molecule and C-O distances of 1.18A. Textbooks contain only a linear CO2-molecule.
PDB-entries contain CO2 in both conformations (1kek,1e5h - linear);1mkm,1krb with 109 degr.)).
Is there really a kinked CO2 or is it a bug in the library
$CCP4/lib/data/monomers/mon_lib_met.cif?
Greetings,
Juergen

 data_comp_CO2
#
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
 CO2      O1   O    O         0.000
 CO2      C    C    C         0.000
 CO2      O2   O    O         0.000
loop_
_chem_comp_tree.comp_id
_chem_comp_tree.atom_id
_chem_comp_tree.atom_back
_chem_comp_tree.back_type
_chem_comp_tree.atom_forward
_chem_comp_tree.connect_type
 CO2      O1   .    .        C    START
 CO2      C    O1   .        .    END
 CO2      O2   C    .        .    .
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
 CO2        C    O1      coval       1.410    0.020
 CO2        O2   C       coval       1.410    0.020
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
 CO2        O1   C    O2    109.470    3.000
#