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Ligand Efficiency Script for StarDrop

Sep 22, 2023

This script provides a method for calculating Ligand Efficiency in StarDrop; a simple quantifiable metric for assessing whether a ligand derives its potency from having an optimal fit with the protein target or simply by virtue of making many contacts. The metric is as follows:

Ligand efficiency equation


This integration is available to use with StarDrop 7.3, 7.4, and 7.5 (Windows and macOS). To find out which version you have installed, start StarDrop and select the Help->About menu.

If you are using an older version of StarDrop (7.2 and earlier), please contact us at [email protected] and we will be happy to help install this script on your StarDrop client.

Installing and using the Ligand Efficiency script for StarDrop

To install this script on Windows:

To install this script on macOS or Windows:

  • Exit StarDrop
  • Download the appropriate file for your StarDrop client:
  • In your user area, navigate to the StarDrop Python folder (on Windows, this is in C:\Users\username\AppData\Roaming\StarDrop\py3, on macOS, this is in ~/StarDrop/py3)
  • Extract the contents of the zip file into this folder overwriting any existing files
  • You should now see the following folders in the StarDrop folder:
    py3\Ligand Efficiency
  • Start StarDrop


To use the Ligand Efficiency script

Click on the Custom Scripts->Calculate Ligand Efficiency menu item in StarDrop. If the open data set contains appropriate data, a dialogue box will appear, prompting for a column against which to calculate ligand efficiency values. The data set must include a Structure column and a pKi column. A µ Ki column can be used instead of a pKi column, given the column is formatted accordingly. You can format a column by right-clicking on the column header and selecting the Edit menu option. Once selected, the script will create a new column next to the chosen one with the calculated values.

If there is no data set open (or the open data set has no appropriate data for calculating ligand efficiency) it will give a message saying that there is no data available for calculation.

For support with this script or anything else please reach out to us at [email protected]