Iridium - A Rapid Way to Assess Structural Quality of Protein-Ligand Complexes

Assessing Structural Quality of Protein-Ligand Complexes – Orion Tip

Looking for a tool to help you quickly judge the quality of protein-ligand structure? Experimental crystal structures vary greatly in quality. Starting with a high-quality crystal structure is often the first - and potentially most important - step in your modeling process.  

OpenEye’s Iridium classification makes it extremely easy for you to assess the quality of protein-ligand structure. The four classifications are:

  • Iridium-HT - Highly Trustworthy
  • Iridium-MT - Mildly Trustworthy
  • Iridium-NT- Not Trustworthy
  • NA – Not enough Available data (for structures where the Iridium classification cannot be determined (e.g. apo binding sites, or lack of electron density maps) 

Choosing protein-ligand complexes categorized by Iridium as Highly Trustworthy (HT) or Mildly Trustworthy (MT) can improve your modeling results.

Iridium classification judges the ligand and the binding site based on the quality of the experimental data, the diffraction precision index (DPI), R-factors, coverage of electron density of the ligand atoms and the binding site atoms. It additionally flags excipients or packing residues potentially affecting the ligand pose. 

Pro Tips and Resources:

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OpenEye Scientific

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