Molecular modelers often face the challenge of categorizing and analyzing vast sets of structural data effectively. In the integrative molecular design platform SAMSON, the Node Specification Language (NSL) empowers users to navigate and filter molecular structures with precision. One essential NSL component is the structural group attributes. This blog post will guide you through these attributes, helping you harness them effectively in your workflow.
Why Structural Group Attributes Matter
Structural group attributes are vital when working with molecular models that contain groupings of atoms or substructures. Whether you’re filtering by chemical properties, visibility settings, or specific atom counts, these attributes offer precise filtering options for molecular nodes.
Inherited and Specific Attributes Explained
Structural group attributes are divided into two categories: inherited attributes and attributes specific to the structuralGroup attribute space. These allow you to manipulate and filter structural groups for different purposes:
Inherited Attributes
hasMaterial(sg.hm): Specifies whether the structural group is associated with material. Example:sg.hm,not sg.hm.hidden(sg.h): Indicates visibility status. Example:sg.h,not sg.h.name(sg.n): Filters groups by their names. String matching is possible. Example:sg.n "A",sg.n "L*".selected(sg.selected): Shows whether the structure is currently selected. Example:sg.selected,not sg.selected.
Specific Structural Group Attributes
These attributes are tailored for the structural group:
formalCharge(sg.fc): Matches groups with a specific total formal charge. Example:sg.fc 6:8,sg.fc > 1.numberOfAtoms(sg.nat): Filters based on atom count. Example:sg.nat 100:200,sg.nat > 100.numberOfCarbons(sg.nC): Filters by the number of Carbon atoms. Example:sg.nC 10:20.numberOfHydrogens(sg.nH): Filters by the number of Hydrogen atoms. Example:sg.nH 10:20.partialCharge(sg.pc): Matches groups with specific partial charges. Example:sg.pc 1.5:2.0,sg.pc > 1.5.
Practical Use Cases
Imagine you’re working with a large biomolecular structure and need to focus only on structural groups containing a specific number of Hydrogen atoms. Using sg.nH, you can write expressions like sg.nH 10:20 to isolate groups with 10–20 Hydrogen atoms. Similarly, to filter by formal charge, sg.fc 6:8 will help zero in on structural groups with a formal charge in the range of 6 to 8.
Want to Learn More?
The attributes listed here represent some of the essential tools for molecular modeling. To dive deeper into additional filtering expressions and scenarios, visit the full documentation on Structural Group Attributes.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON at SAMSON Connect.