Understanding Backbone Attributes in the Node Specification Language (NSL).

Molecular modeling often involves intricate structures, and optimizing processes for identifying and manipulating specific attributes can save substantial time and effort. If you’ve ever needed a precise way to work with backbone attributes in your designs, SAMSON’s Node Specification Language (NSL) offers dedicated tools to make this task more efficient. This post will introduce backbone-specific attributes in NSL and provide clarity on how they can streamline molecular modeling workflows.

What are Backbone Attributes?

In the NSL, backbone attributes form a specific attribute space (abbreviated as s) dedicated to working exclusively with backbone nodes within molecular models. These attributes provide ways to inspect or manipulate backbone-specific properties, like visibility, material ownership, and atomic compositions. By using NSL expressions, you can target and filter nodes based on these attributes to meet the needs of your design tasks.

Key Backbone Attributes and Their Usage

The following are some of the most commonly used backbone attributes categorized by their inheritance points:

Attributes Inherited from the Node Attribute Space

  • hasMaterial (hm): Indicates whether the node has material. Possible values are true or false. For example, use bb.hm to check if a backbone node has material.
  • hidden (h): Shows the visibility status. Use bb.h for hidden nodes or not bb.h to filter nodes that are not hidden.
  • name (n): Matches nodes based on a name. For example, bb.n "A" finds nodes named “A,” and bb.n "L*" locates names starting with “L.”
  • ownsMaterial (om): Specifies whether the node owns any materials. Possible values are true or false.
  • selected: Indicates selection states of nodes, with no short name available. Similar boolean filtering can be performed as in bb.selected or not bb.selected.
  • visibilityFlag (vf): Defines whether the node visibility flag is set. Examples include bb.vf or bb.vf false.

Attributes Inherited from the Structural Group Attribute Space

  • formalCharge (fc): Represents the formal charge on a backbone, returned as an integer. For instance, use bb.fc > 1 to find nodes with a formal charge greater than 1.
  • numberOfAtoms (nat): Filters based on the total number of atoms. For example, bb.nat < 100:200 identifies backbones with atomic counts between 100 and 200.
  • numberOfCarbons (nC), numberOfNitrogens (nN), numberOfHydrogens (nH), numberOfOxygens (nO), and numberOfSulfurs (nS): Allow targeted queries regarding the count of specific atom types.
  • partialCharge (pc): A float value representing the partial charge of the node. Use bb.pc > 1.5 or bb.pc 1.5:2.0 for filtering.

Why Backbone Attributes Matter

Whether you are investigating the properties of molecular structures, modifying designs, or ensuring that specific features are present (or absent), backbone attributes give you direct control. From identifying hidden components to targeting nodes based on their atom composition, NSL simplifies what might otherwise involve lengthy manual inspections or less precise search methods.

Learn More

By leveraging backbone attributes in NSL, molecular modelers can optimize workflows, increase precision, and reduce tedious tasks. To explore a complete list of backbone attributes and their possible applications, visit the Backbone NSL documentation page.

Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at SAMSON Connect.

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