Understanding Side Chain Attributes in SAMSON’s NSL

Molecular modelers often deal with the need for precise structural analysis of side chains in molecular systems. When working with SAMSON’s Node Specification Language (NSL), understanding how to select and query side chain attributes can save you significant time and effort. Let’s explore how you can work with these attributes effectively.

What Are Side Chain Attributes?

In SAMSON, side chain attributes belong to the sideChain attribute space, which is denoted by the short name s. These attributes are specific to side chain nodes and allow you to filter, select, and analyze the desired molecular features quickly.

Key Side Chain Attributes

Let’s take a look at some of the most useful side chain attributes you can leverage:

  • sc.hasMaterial (hm): Checks whether the side chain has associated material. Example: sc.hm, not sc.hm.
  • sc.hidden (h): Indicates whether the side chain is hidden. Example: sc.h, not sc.h.
  • sc.name (n): Matches string values to identify specific side chains. Example: sc.n "A", sc.n "L*".
  • sc.ownsMaterial (om): Checks if the side chain owns material. Example: sc.om.
  • sc.selected: Checks if the side chain is selected. Example: sc.selected, not sc.selected.
  • sc.numberOfAtoms (nat): Filters side chains by the number of atoms. Example: sc.nat < 1000, sc.nat 100:200.

You can also use attributes like numberOfCarbons (sc.nC), numberOfHydrogens (sc.nH), and even partialCharge (sc.pc), which are crucial for analyzing chemical composition or charge distribution across side chains.

Inheritance Makes It Powerful

One of the strengths of SAMSON’s NSL is its attribute inheritance. Attributes inherited from the node or structuralGroup attribute spaces expand the applicability of side chain queries. For instance:

  • sc.visibilityFlag (vf): The visibility status of the side chain. Example: sc.vf false.
  • sc.formalCharge (fc): The formal charge on the side chain, inherited from the structuralGroup. Example: sc.fc > 1, sc.fc 6:8.

These inherited attributes allow users to apply both general and specific filters, enabling highly targeted molecular modeling workflows.

Applying Side Chain Attribute Queries

The most practical aspect of using these attributes is their straightforward syntax. For instance, if you want to select side chains containing fewer than ten carbons and a formal charge beyond 1.5, you can write:

This intuitive selection process accelerates decision-making for molecular modelers and allows you to focus on studying structurally relevant components of your system.

Why Should You Care?

Using side chain attributes in SAMSON significantly improves your ability to perform complex queries with fewer errors and within shorter time frames. For professionals dealing with structure-based drug design or who analyze biomolecular properties, this built-in precision can be a game-changer.

For more details on side chain attributes, visit the official documentation.

SAMSON and all SAMSON Extensions are free for non-commercial use. Explore endless possibilities in molecular design by downloading SAMSON from SAMSON Connect.

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