Molecular modelers frequently encounter challenges when preparing and optimizing complex systems for accurate protein-ligand docking. Time-consuming preparation steps, such as cleaning up structural files, optimizing ligand geometry, and setting up flexible docking workflows, can be a bottleneck in the design process. The FITTED Suite SAMSON Extension presents a powerful solution to these challenges by automating and optimizing docking workflows, including both covalent and non-covalent docking.
In this blog post, we will guide you through the streamlined process of non-covalent docking within SAMSON using the FITTED Suite. This extension leverages advanced tools such as PREPARE, PROCESS, SMART, and CONVERT to handle protein and ligand preparation tasks, allowing researchers to focus on interpreting results rather than laborious setup routines.
Automating the Non-Covalent Docking Workflow
Let’s focus on an example where the FITTED Suite is used to set up and perform non-covalent docking for the thymidine kinase protein (1E2K) with its ligand ((N)-methanocarba-thymidine, TMC 500).
Step 1: Loading the Protein-Ligand System
Begin by launching SAMSON and opening the file 1E2K-A.sam. This file provides a structural model of the thymidine kinase protein bound to the ligand TMC 500. You can visualize the molecule hierarchy in the Document view to inspect individual components of the system.
Step 2: Preparation of the System
To ensure accuracy, the FITTED Suite automatically prepares the system by adjusting bond orders, adding hydrogens, and optimizing the hydrogen-bond network. For most cases, this preparation step is seamlessly handled in the background, allowing you to proceed directly to the docking setup.
Step 3: Setting Up the Docking System
Next, open the FITTED Suite from the Home > Apps > Biology menu. Here, you will define the receptor, binding site, and ligand:
- Receptor: Select the
1E2Kprotein in the document. Use the “Set receptor” option to designate it as the docking receptor. - Binding site: For self-docking, define the binding site based on the bound ligand
TMC 500. Simply select the ligand in the document and use the “Set binding site” option. - Ligand: Similarly, designate
TMC 500as the docking ligand by choosing “Set ligand” in the FITTED Suite and ensuring ligand preparation options like perceiving bond order and adding hydrogens are activated.
Step 4: Running the Docking
Now, configure the docking parameters. For this example, set the docking mode to Non-covalent, specify the number of runs (e.g., 2), and optionally choose to import only the best pose. Define the output folder for saving results, then click the Dock button to start the calculation. The FITTED Suite will display progress updates during the docking process.
Step 5: Analyzing the Results
Upon completion, the results are automatically imported into the document and displayed in a results table. This table allows for quick access to docking results, including detailed poses and scores. Selecting a row highlights the corresponding pose in the document.
To visualize the docking results, you can enhance the 3D representation using visual models such as Ribbons for the receptor and Licorice for ligand-surrounding residues. Experiment with different visual and analysis tools within SAMSON to explore ligand-receptor interactions.
Simplify Your Protein-Ligand Docking
The FITTED Suite in SAMSON makes protein-ligand docking workflows efficient, customizable, and user-friendly, tackling common challenges faced by molecular modelers. By automating the preparation, visualization, and analysis processes, researchers can focus on interpreting data and moving their projects forward.
If you’re looking to learn more about non-covalent and covalent docking workflows with the FITTED Suite, visit the original documentation page.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can get your free copy of SAMSON at SAMSON Connect.