Streamline Non-Covalent Protein-Ligand Docking with the SAMSON FITTED Suite

Protein-ligand docking is an intricate process, but with the right tools, it becomes far more manageable. For molecular modelers grappling with non-covalent docking, the SAMSON FITTED Suite offers a streamlined, user-friendly approach. In this post, we’ll walk you through how to perform non-covalent docking using the FITTED Suite and simplify complex workflows.

Why Non-Covalent Docking Matters

Non-covalent docking plays a crucial role in understanding molecular interactions, predicting binding modes, and even guiding the drug discovery process. However, setting up robust docking workflows can be overwhelming, especially when juggling receptor and ligand preparation, grid settings, and parameter tuning. The FITTED Suite simplifies these tasks, automating steps while allowing for customization where needed.

Getting Started with Non-Covalent Docking in SAMSON

First, launch SAMSON and open the 1E2K-A.sam file provided in the tutorial archive. This file contains a structural model of a thymidine kinase protein (code 1E2K) and its bound ligand ((N)-methanocarba-thymidine, TMC 500). Importing this file will display the receptor-ligand complex in SAMSON’s Document view and provide the foundation for the docking workflow.

A document with 1E2K structure

Step 1: Setting Up the Receptor

In the FITTED Suite plugin (accessible via Home > Apps > Biology), select the 1E2K structural model as the receptor:

  • In the “Set receptor” section, choose From document and click Set.
  • Leave water molecules and macromolecules parameters at their default values (Protein).

This step ensures your receptor is ready for docking without requiring extensive manual preprocessing.

Step 2: Defining the Binding Site

Defining the binding site is straightforward, especially when dealing with self-docking scenarios like this tutorial:

  • Use “From bound ligand” and select the TMC 500 ligand from chain A.
  • Click Set to define the binding site based on the ligand’s location.

Selected TMC500 ligand

Step 3: Preparing the Ligand

Similarly, select the TMC 500 ligand in the Document view and set it as the ligand in the FITTED Suite:

  • In the “Set ligand” section, choose From document.
  • Leave the option to prepare the ligand (perceive bond order and add hydrogens) checked.

By automating ligand preparation, the plugin ensures accurate 3D representations without additional effort.

Set ligand UI

Step 4: Setting Docking Parameters

Before running the docking, specify the parameters that shape the docking simulation:

  • Set the number of runs to 2.
  • Check “Import the best pose only” if desired.
  • Choose Non-covalent as the docking mode.

Docking parameters

Set an output folder for saving results and click Dock to begin the simulation. Depending on your system, the process should only take a few minutes.

Step 5: Analyzing Results

Once the docking completes, results appear in a table and are automatically added to your SAMSON Document view. The visualized processed receptor integrates hydrogens, while the ligand pose displays precise binding configurations.

Results table

You can export the results in CSV format and fine-tune visualizations. For instance:

  • Use Ribbons to display the receptor’s secondary structure.
  • Add licorice visuals for residues near the binding site.

Secondary structure representation of the receptor

Why Choose the FITTED Suite?

The FITTED Suite’s automation and precise tools make non-covalent docking accessible to molecular modelers of all skill levels. From system preparation to result visualization, it ensures a smooth, error-resistant workflow.

Learn more about the complete process and other functionalities by visiting the official documentation page.

Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at https://www.samson-connect.net.

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