Molecular modeling often involves vast data, complex structures, and atom-level details. For a molecular modeler, efficiently navigating this complexity to extract meaningful insights can be challenging. The good news is that SAMSON’s Node Specification Language (NSL) provides powerful tools to query and analyze molecular models systematically. In this post, we’ll explore StructuralModel attributes, a vital component of NSL, which simplifies working with structural models and their properties.
Why StructuralModel Attributes Matter
Whether you’re searching for subunits with specific properties in a protein or inspecting groups in a molecule, StructuralModel attributes provide a succinct and logical way to specify queries. These attributes define criteria such as the number of atoms, chains, or even elemental counts within a structure. This systematic query approach can save you hours of manual work and help automate repetitive analysis tasks.
An Overview of Key Attributes
The structuralModel attribute space organizes attributes into two categories: inherited attributes and structural-specific attributes. Let’s delve into some of the most impactful ones:
Inherited Attributes
1. Visibility Control: Attributes like visible (sm.v) and hidden (sm.h) allow you to identify or filter models based on their visibility in a workspace. These are useful when handling large models where some components might be hidden for clarity.
2. Selection: Attributes such as selected (sm.selected) make it possible to target only those elements currently selected in your project.
Structural-Specific Attributes
1. Numbering Atoms, Elements, and Molecules: Attributes like numberOfAtoms (sm.nat) or numberOfCarbons (sm.nC) enable filtering based on specific structural data. For instance: sm.nat > 100 matches structural models with more than 100 atoms.
2. Formal and Partial Charges: Attributes like formalCharge (sm.fc) target structures with specific total charges, while partialCharge (sm.pc) works with real numbers to match partial charges. This is particularly useful for electrostatic studies or charge balancing.
3. Chain and Segment Details: The numberOfChains (sm.nc) or numberOfSegments (sm.ns) attributes let you manipulate data based on higher-level structural organization.
Practical Examples
Here are two quick examples illustrating how to use these attributes effectively:
sm.nC < 10: Matches structural groups with fewer than 10 carbon atoms. Great for identifying smaller hydrophobic chains or substructures.sm.nr 100:130: Finds structural models containing between 100 and 130 residues. This is especially handy for filtering medium-sized proteins in your dataset.
More complex expressions can combine several criteria, making the NSL extremely adaptable to your needs.
How to Learn More
The StructuralModel attributes are explained in even greater detail, with numerous examples, on the official documentation page. To dive in further, be sure to visit the dedicated section for StructuralModel attributes at SAMSON’s Documentation.
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