For molecular modelers, precision at the sub-molecular level can make all the difference. Whether you’re crafting a new molecule or fine-tuning an existing one, optimizing specific parts rather than the entire structure is often critical. This is where SAMSON’s ability to minimize only parts of molecules comes in handy—a feature that can save you time while ensuring high accuracy in structural refinement.
Why Minimize Only Part of a Molecule?
Imagine working on a large, complex molecule. Perhaps you’re only interested in tweaking a functional group or adjusting a specific region without disturbing the rest of the geometry. Global minimization can affect areas you’d rather leave untouched, introducing unnecessary changes. Thankfully, with SAMSON, there’s a solution: freezing the sections you want to preserve and focusing minimization efforts on your region of interest.
How Does Partial Minimization Work in SAMSON?
SAMSON offers a straightforward workflow to minimize only specific parts of a molecule:
- Select the Entire Molecule or Keep the Selection Empty: Begin by choosing the molecule you want to work on, or leave it as is if no prior selection is needed.
- Freeze Atoms: Next, click
Edit > Freeze. This action fixes the selected atoms—or the entire molecule if no selection was made—ensuring they remain stationary during the optimization. - Refine Your Selection: After freezing, pinpoint the exact part of the molecule you’d like to optimize by selecting it.
- Unfreeze and Minimize: Now, unfreeze the selected region using
Edit > Unfreeze, and start the interactive minimization by clickingEdit > Minimize.
When the minimization process is complete, you can finalize by unfreezing the entire system (if needed) to restore the molecule to an editable state.
Visualizing Frozen Atoms
A helpful feature in SAMSON is the ability to visually distinguish frozen atoms—they appear with a dark blue overlay in the viewport. This ensures that you can clearly identify which parts of the molecule are stationary during the minimization process. By isolating regions of interest, you maintain precise control over the changes applied to your structure.
When to Use This Workflow
The “freeze-and-minimize” method is especially beneficial in scenarios such as:
- Stabilizing a newly added functional group without affecting the rest of the molecule.
- Adjusting specific regions of polymers or complexes.
- Focusing on a molecular section that interacts with a ligand or another molecule.
Learn More
If you want to delve into the technical steps and additional details about minimization in SAMSON, explore the official documentation page at https://documentation.samson-connect.net/users/latest/minimizing/.
SAMSON and all SAMSON Extensions are free for non-commercial use. To download SAMSON and start exploring, visit https://www.samson-connect.net.