Preparing your protein system is a critical yet often overlooked step when performing protein docking. Neglecting proper preparation can lead to inaccurate docking results, confusion arising from structural irregularities, or wasted time troubleshooting issues. In this post, we’ll cover how SAMSON enables you to efficiently prepare your protein systems for docking with the Hex Extension, ensuring smooth workflows and reliable results.
Why Proper Protein Preparation Matters
Successful protein docking relies on the structural integrity and chemical composition of the input molecules. Issues like the presence of water molecules, unprotonated residues, alternate atom positions, or missing atoms can distort results. Proper preparation ensures the system is chemically accurate and structurally ready for docking algorithms to work as intended.
Preparing a Protein System in SAMSON
In SAMSON, the process of preparing a protein system can be done through a straightforward workflow. Here’s how:
Step 1: Open the system in SAMSON. You can either load your own receptor and ligand structures or use a tutorial sample file. For this tutorial, we refer to the included example file which contains the proteins 2PTC_E and 2PTC_I.
Step 2: Go to Home > Prepare and configure the preparation settings. SAMSON allows you to:
- Remove alternate atom positions to ensure structural clarity.
- Remove water molecules, monatomic ions, or ligands that could interfere with docking simulations.
- Add missing hydrogens for proper protonation states. If your structure already includes hydrogen atoms added based on specific conditions, it’s important not to overwrite them.
The figure below shows the preparation options in SAMSON:
Fixing More Complex Issues
If your protein structure has missing residues or atoms (e.g., heavy atoms in side chains), the PDBFixer Extension is an excellent tool. It can fill in missing components and even adjust protonation states for a target pH, making it a versatile helper for demanding projects.
See also
You can learn more about cleaning and fixing protein structures in the Protein Preparation & Validation tutorial.
Note
If you use the tutorial file, you’ll find the system has already been cleaned, with water removed and hydrogens added. However, in real cases, it’s essential to manually verify and prepare your own systems!
Ensuring Clear Visualization
Secondary structure visualization can improve clarity during preparation. To add secondary structures, follow these steps:
- Select the protein model in the Document view.
- Navigate to Visualization > Visual model > Ribbons.
Toggle the boxes for the atomistic representation to declutter your view as needed. Convenient visual aids like this are available in SAMSON’s user-friendly interface.
Take Control of Your Docking Workflow
System preparation is an essential component of any successful protein docking workflow. SAMSON, together with tools like Hex and PDBFixer, provides a precise and user-friendly way to clean and ready protein systems for accurate docking results. By following proper preparation practices, you’ll not only gain more reliable outputs but also save significant time in troubleshooting errors that can arise during the docking process.
Remember that detailed documentation and visual examples can provide additional guidance and insights tailored for specific needs. To learn more, visit the official documentation page at https://documentation.samson-connect.net/tutorials/hex/protein-docking-with-hex/.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at https://www.samson-connect.net.