If you often work with molecular models, you know that pinpointing specific subsets of your data efficiently can be a challenge, especially when it comes to structural or conformational elements. Thankfully, SAMSON’s Node Specification Language (NSL) helps streamline these tasks, offering robust filtering capabilities to navigate and extract information from molecular structures. In this post, we’ll dive into the “Path Attributes” feature of NSL, providing you with practical insights on leveraging it to simplify your workflows.
Why Path Attributes Matter
The path attribute space in NSL is particularly useful when dealing with conformation nodes. Attributes defined in this space allow users to interrogate and extract information about paths—an essential concept when observing molecular conformations. Whether you’re selecting paths based on the number of atoms or working with specific selection flags, path attributes embed flexibility and precision into the modeling process.
Key Attributes You Should Know
Let’s explore some commonly used attributes within the path attribute space and how to employ them effectively in your workflows:
1. numberOfAtoms (nat)
The numberOfAtoms attribute (p.nat for short) enables you to select paths based on how many atoms they contain. This is particularly useful for filtering large datasets or focusing on specific molecular regions.
Possible Values: Integers
Examples:
p.nat > 100: Selects paths with more than 100 atoms.p.nat 100:200: Selects paths with a number of atoms between 100 and 200.
These filters allow you to systematically narrow down paths with desired atomic properties, making analysis much more targeted and efficient.
2. selected and selectionFlag
Inherited from the general node attribute space, selected and selectionFlag are crucial for determining subsets of selected paths within your molecular system.
For example:
p.selected: Matches paths that are currently selected.not p.selected: Matches paths that are not selected.p.sf false: Matches paths where the selection flag is set tofalse.
These attributes are vital when pinpointing specific paths without manually scanning through the model. Whether you need to analyze unselected structures or toggle selection flags, they save significant time while improving precision.
3. name (n)
The name attribute (p.n) allows you to match paths by their name. Use this attribute for quick filtering or to isolate paths based on naming conventions.
Example Filters:
p.n "A": Matches paths explicitly named “A”.p.n "L*": Matches paths whose names start with “L”.
This feature is particularly helpful when working in large molecular models with numerous named entities.
Where to Start: Practical Examples
Imagine you’re investigating a large molecular system and want to isolate conformations along specific properties:
- To find all paths with more than 100 atoms, use:
p.nat > 100 - To exclude currently selected paths and focus on the rest, use:
not p.selected - To target paths with names starting with “Ligand,” use:
p.n "Ligand*"
These simple queries can save hours of manual scrolling and help you zero in on exactly what you need.
Explore Further
Path attributes greatly enhance your ability to handle molecular data with precision and speed. To explore the full range of capabilities offered by the path attribute space, visit the official documentation page.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Download SAMSON from SAMSON Connect.