Molecular modeling often requires precise control and analysis of structural models. Whether you’re studying complex proteins, designing molecules, or exploring atomic details, SAMSON’s structuralModel attribute space simplifies these tasks, offering a powerful way to query and manipulate molecular data. If you’re not fully leveraging the attributes within the structuralModel attribute space, you might be tackling challenges the hard way. Let’s walk through some essential attributes and see how they make your modeling tasks more efficient.
What Are Structural Model Attributes?
In SAMSON, structural model attributes allow users to filter molecular nodes with specific properties. Defined within the structuralModel attribute space (short name: sm), these attributes make it possible to select and analyze structural models by characteristics like the number of atoms, specific atom types, material properties, and more. For example, let’s say you’re trying to identify molecular structures with fewer than 10 sulfur atoms or filter by a target number of residues. Structural model attributes enable you to perform such queries effortlessly.
Examples of Frequently Used Attributes
Here’s a brief overview of some common attributes:
- numberOfAtoms (
sm.nat): Matches structural models with a specific number of atoms. To identify structures with fewer than 1,000 atoms, usesm.nat < 1000. - numberOfCarbons (
sm.nC): Useful for isolating structures with Carbon atoms by specifying a range, such assm.nC 10:20. - formalCharge (
sm.fc): Matches molecules based on their formal charge. If you wanted models with a total charge between 6 and 8, you’d usesm.fc 6:8. - visibilityFlag (
sm.vf) and visible (sm.v): Determine whether structural nodes are in view or hidden from view. - numberOfResidues (
sm.nr): A critical attribute for protein modelers, allowing you to specify residue counts such assm.nr > 130. - partialCharge (
sm.pc): Helpful for selecting models by the total partial charge, e.g.,sm.pc 1.5:2.0.
Combining these attributes makes precise filtering and analysis scalable, even with large and complex datasets.
Attribute Interactions
For even more power, SAMSON also allows inherited attributes from the node attribute space, enabling advanced filtering strategies. For example, combining properties such as visibility (sm.visible) with custom ranges like sm.nO 10:15 (filtering by Oxygen atoms) ensures you’re focusing on the most relevant structural data in your modeling workflow.
Practical Usage Example
Let’s say you’re modeling biomolecules and need a molecular group that meets the following conditions:
- Contains fewer than 500 atoms (
sm.nat < 500). - Includes at least 3 chains (
sm.nc > 3). - Has between 2 and 10 Carbon atoms (
sm.nC 2:10).
Your query might look something like:
|
1 |
sm.nat < 500 and sm.nc > 3 and sm.nC 2:10 |
This concise and readable query saves time while providing precise results—perfect for optimizing your workflow.
Conclusion
SAMSON’s structural model attributes provide a great way to simplify molecular design and analysis. They’re versatile, powerful, and designed with modelers in mind. By mastering them, you’ll find filtering and analyzing molecular models to be less time-consuming and more insightful.
For a deeper dive into structural model attributes, and examples of how to apply them to more specific problems, visit the online SAMSON documentation.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at SAMSON Connect.