<?xml version="1.0" encoding="UTF-8" ?>

<PDBx:datablock datablockName="3IW"
   xmlns:PDBx="http://pdbml.pdb.org/schema/pdbx-v50.xsd"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xsi:schemaLocation="http://pdbml.pdb.org/schema/pdbx-v50.xsd pdbx-v50.xsd">

   <PDBx:chem_compCategory>
      <PDBx:chem_comp id="3IW">
         <PDBx:formula>C3 H2 Fe N O2</PDBx:formula>
         <PDBx:formula_weight>139.898</PDBx:formula_weight>
         <PDBx:name>(cyanido-kappaC)diformyliron</PDBx:name>
         <PDBx:pdbx_ambiguous_flag>N</PDBx:pdbx_ambiguous_flag>
         <PDBx:pdbx_comp_type>metal-containing ligand</PDBx:pdbx_comp_type>
         <PDBx:pdbx_ideal_coordinates_details>MetalCoord</PDBx:pdbx_ideal_coordinates_details>
         <PDBx:pdbx_ideal_coordinates_missing_flag>N</PDBx:pdbx_ideal_coordinates_missing_flag>
         <PDBx:pdbx_initial_date>2026-05-19</PDBx:pdbx_initial_date>
         <PDBx:pdbx_model_coordinates_db_code>1WUL</PDBx:pdbx_model_coordinates_db_code>
         <PDBx:pdbx_model_coordinates_missing_flag>N</PDBx:pdbx_model_coordinates_missing_flag>
         <PDBx:pdbx_modified_date>2026-08-07</PDBx:pdbx_modified_date>
         <PDBx:pdbx_release_status>REL</PDBx:pdbx_release_status>
         <PDBx:pdbx_type>HETAIN</PDBx:pdbx_type>
         <PDBx:three_letter_code>3IW</PDBx:three_letter_code>
         <PDBx:type>non-polymer</PDBx:type>
      </PDBx:chem_comp>
   </PDBx:chem_compCategory>
   <PDBx:chem_comp_atomCategory>
      <PDBx:chem_comp_atom atom_id="FE" comp_id="3IW">
         <PDBx:alt_atom_id>FE</PDBx:alt_atom_id>
         <PDBx:model_Cartn_x>55.734</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>49.113</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>86.407</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>0</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>FE</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>0.011</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>0.085</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>-0.556</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>1</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>FE</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="C3" comp_id="3IW">
         <PDBx:alt_atom_id>C3</PDBx:alt_atom_id>
         <PDBx:charge>-1</PDBx:charge>
         <PDBx:model_Cartn_x>56.046</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>50.862</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>86.674</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>C3</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>-1.314</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>-0.265</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>0.590</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>2</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>C</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="C2" comp_id="3IW">
         <PDBx:alt_atom_id>C2</PDBx:alt_atom_id>
         <PDBx:charge>-1</PDBx:charge>
         <PDBx:model_Cartn_x>53.808</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>49.411</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>86.817</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>C2</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>0.230</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>1.807</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>-0.148</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>3</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>C</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="O3" comp_id="3IW">
         <PDBx:alt_atom_id>O3</PDBx:alt_atom_id>
         <PDBx:charge>0</PDBx:charge>
         <PDBx:model_Cartn_x>56.232</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>51.922</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>86.956</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>O3</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>-1.974</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>-0.655</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>-0.400</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>4</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>O</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="N2" comp_id="3IW">
         <PDBx:alt_atom_id>N2</PDBx:alt_atom_id>
         <PDBx:charge>0</PDBx:charge>
         <PDBx:model_Cartn_x>52.768</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>49.769</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>87.093</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>N2</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>0.384</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>3.014</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>0.139</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>5</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>N</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="O1" comp_id="3IW">
         <PDBx:alt_atom_id>O1</PDBx:alt_atom_id>
         <PDBx:charge>0</PDBx:charge>
         <PDBx:model_Cartn_x>56.352</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>48.152</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>89.335</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>O1</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>1.193</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>-1.678</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>-0.496</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>6</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>O</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="C1" comp_id="3IW">
         <PDBx:alt_atom_id>C1</PDBx:alt_atom_id>
         <PDBx:charge>-1</PDBx:charge>
         <PDBx:model_Cartn_x>56.155</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>48.555</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>88.309</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>C1</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>1.346</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>-0.735</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>0.313</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>7</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>C</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="H3" comp_id="3IW">
         <PDBx:alt_atom_id>H3</PDBx:alt_atom_id>
         <PDBx:charge>0</PDBx:charge>
         <PDBx:model_Cartn_x>56.111</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>51.071</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>85.616</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>H3</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>-0.835</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>0.022</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>1.341</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>8</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>H</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
      <PDBx:chem_comp_atom atom_id="H1" comp_id="3IW">
         <PDBx:alt_atom_id>H1</PDBx:alt_atom_id>
         <PDBx:charge>0</PDBx:charge>
         <PDBx:model_Cartn_x>56.524</PDBx:model_Cartn_x>
         <PDBx:model_Cartn_y>49.536</PDBx:model_Cartn_y>
         <PDBx:model_Cartn_z>88.569</PDBx:model_Cartn_z>
         <PDBx:pdbx_align>1</PDBx:pdbx_align>
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_component_atom_id>H1</PDBx:pdbx_component_atom_id>
         <PDBx:pdbx_component_comp_id>3IW</PDBx:pdbx_component_comp_id>
         <PDBx:pdbx_leaving_atom_flag>N</PDBx:pdbx_leaving_atom_flag>
         <PDBx:pdbx_model_Cartn_x_ideal>1.474</PDBx:pdbx_model_Cartn_x_ideal>
         <PDBx:pdbx_model_Cartn_y_ideal>-0.041</PDBx:pdbx_model_Cartn_y_ideal>
         <PDBx:pdbx_model_Cartn_z_ideal>0.927</PDBx:pdbx_model_Cartn_z_ideal>
         <PDBx:pdbx_ordinal>9</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:type_symbol>H</PDBx:type_symbol>
      </PDBx:chem_comp_atom>
   </PDBx:chem_comp_atomCategory>
   <PDBx:chem_comp_bondCategory>
      <PDBx:chem_comp_bond atom_id_1="FE" atom_id_2="C3" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>1</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>sing</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="FE" atom_id_2="C2" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>2</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>sing</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="FE" atom_id_2="C1" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>3</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>sing</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="C3" atom_id_2="O3" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>4</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>doub</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="C3" atom_id_2="H3" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>5</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>sing</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="C2" atom_id_2="N2" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>6</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>trip</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="O1" atom_id_2="C1" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>7</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>doub</PDBx:value_order>
      </PDBx:chem_comp_bond>
      <PDBx:chem_comp_bond atom_id_1="C1" atom_id_2="H1" comp_id="3IW">
         <PDBx:pdbx_aromatic_flag>N</PDBx:pdbx_aromatic_flag>
         <PDBx:pdbx_ordinal>8</PDBx:pdbx_ordinal>
         <PDBx:pdbx_stereo_config>N</PDBx:pdbx_stereo_config>
         <PDBx:value_order>sing</PDBx:value_order>
      </PDBx:chem_comp_bond>
   </PDBx:chem_comp_bondCategory>
   <PDBx:pdbx_chem_comp_auditCategory>
      <PDBx:pdbx_chem_comp_audit action_type="Create component" comp_id="3IW" date="2026-05-19">
      </PDBx:pdbx_chem_comp_audit>
      <PDBx:pdbx_chem_comp_audit action_type="Other modification" comp_id="3IW" date="2026-07-31">
         <PDBx:processing_site>RCSB</PDBx:processing_site>
      </PDBx:pdbx_chem_comp_audit>
      <PDBx:pdbx_chem_comp_audit action_type="Initial release" comp_id="3IW" date="2026-08-12">
         <PDBx:processing_site>RCSB</PDBx:processing_site>
      </PDBx:pdbx_chem_comp_audit>
   </PDBx:pdbx_chem_comp_auditCategory>
   <PDBx:pdbx_chem_comp_descriptorCategory>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="ACDLabs" program_version="14.52" type="SMILES">
         <PDBx:descriptor>N#C[Fe](C=O)C=O</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="InChI" program_version="1.06" type="InChI">
         <PDBx:descriptor>InChI=1S/CN.2CHO.Fe/c3*1-2;/h;2*1H;</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="InChI" program_version="1.06" type="InChIKey">
         <PDBx:descriptor>AWYUYDLUJZAIJH-UHFFFAOYSA-N</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="CACTVS" program_version="3.385" type="SMILES_CANONICAL">
         <PDBx:descriptor>O=C[Fe](C=O)C#N</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="CACTVS" program_version="3.385" type="SMILES">
         <PDBx:descriptor>O=C[Fe](C=O)C#N</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="OpenEye OEToolkits" program_version="3.1.0.0" type="SMILES_CANONICAL">
         <PDBx:descriptor>C(=O)[Fe](C=O)C#N</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
      <PDBx:pdbx_chem_comp_descriptor comp_id="3IW" program="OpenEye OEToolkits" program_version="3.1.0.0" type="SMILES">
         <PDBx:descriptor>C(=O)[Fe](C=O)C#N</PDBx:descriptor>
      </PDBx:pdbx_chem_comp_descriptor>
   </PDBx:pdbx_chem_comp_descriptorCategory>
   <PDBx:pdbx_chem_comp_identifierCategory>
      <PDBx:pdbx_chem_comp_identifier comp_id="3IW" program="ACDLabs" program_version="14.52" type="SYSTEMATIC NAME">
         <PDBx:identifier>(cyanido-kappaC)diformyliron</PDBx:identifier>
      </PDBx:pdbx_chem_comp_identifier>
      <PDBx:pdbx_chem_comp_identifier comp_id="3IW" program="OpenEye OEToolkits" program_version="3.1.0.0" type="SYSTEMATIC NAME">
         <PDBx:identifier>cyano(dimethanoyl)iron</PDBx:identifier>
      </PDBx:pdbx_chem_comp_identifier>
   </PDBx:pdbx_chem_comp_identifierCategory>
</PDBx:datablock>
