Molecular modelers often need precise ways to select and analyze specific structures within their systems. Navigating complex molecular data can be challenging without the right tools, and SAMSON’s ‘Path Attributes’ in the Node Specification Language (NSL) can provide an effective solution. In this post, we’ll explore how path attributes can help you make targeted selections and improve your modeling workflow.
An Introduction to Path Attributes
In SAMSON’s NSL, path attributes are confined to the path attribute space (short name: p) and are specifically designed to match conformation nodes. These attributes allow you to define and filter molecular paths based on specific criteria, such as the number of atoms they contain or their selected status. By understanding and effectively using these attributes, you can increase the efficiency of your modeling tasks.
Using numberOfAtoms (p.nat)
If you’ve ever struggled to isolate segments or conformations based on their size, the path.numberOfAtoms attribute (p.nat) offers a straightforward solution. This attribute allows you to filter paths by the number of atoms they contain. For instance:
p.nat > 100: Matches paths containing more than 100 atoms.p.nat 100:200: Matches paths with an atom count between 100 and 200.
This capability is particularly useful for identifying and studying large molecular structures or filtering smaller segments from a complex system.
Working with selected and selectionFlag
Sometimes, it’s critical to focus only on highlighted or pre-selected portions of a molecular model. The selected and selectionFlag attributes make this possible:
p.selected: Matches paths that are currently selected in the workspace.not p.selected: Excludes selected paths.p.sf: Checks the custom selection flag status (trueorfalse).
These attributes are essential for narrowing down your focus, especially when working on specific conformations in large or complex models.
Putting It All Together
Let’s say you’re analyzing a molecular system and need to focus on conformations with 150–300 atoms that haven’t been selected yet. Using NSL, you can combine attributes like this:
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p.nat 150:300 and not p.selected |
This straightforward query saves time and ensures that you’re concentrating on the most relevant parts of your model.
Why Use Path Attributes?
Path attributes empower molecular modelers by providing highly specific filters and selection criteria. Whether you’re analyzing detailed protein conformations or isolating small active sites, these tools facilitate precise control without unnecessary complexity.
For more information on path attributes and additional examples, please visit the documentation page.
SAMSON and all SAMSON Extensions are free for non-commercial use. Download SAMSON today at samson-connect.net.