Efficient molecular modeling often demands precise control over the representations of molecule chains. For SAMSON users, the Chain Attributes feature offers granular customization options via the chain attribute space. In this blog post, we’ll explore how these attributes can help you manage molecule chains more effectively, paving the way for improved workflows in molecular design.
What Are Chain Attributes?
Chain attributes in SAMSON are specific properties assigned to chain nodes, offering ways to query and filter them. These are defined within the chain attribute space (short form: c). To make molecular modeling more flexible, these attributes are subdivided into three key categories:
- Attributes inherited from the node attribute space
- Attributes inherited from the structuralGroup attribute space
- Attributes unique to the
chainattribute space
Practical Applications of Chain Attributes
Let’s dive into some practical examples of how chain attributes can enhance molecular modeling:
1. Visibility and Selection
Ever needed to hide specific molecular chains for clarity? With attributes like hidden (c.h) or visible (c.v), you can easily specify which chains are displayed. For instance:
c.h: Matches hidden chains.not c.h: Matches visible chains.c.selected: Matches chains that are currently selected in the interface.
2. Chain Composition
Modeling depends heavily on understanding the elemental composition of chains. With attributes like numberOfCarbons (c.nC) or numberOfOxygens (c.nO), you can filter chains by the number of specific elements they contain. For example:
c.nC < 10: Matches chains with fewer than 10 carbon atoms.c.nH 10:20: Matches chains containing between 10 and 20 hydrogen atoms.
3. Custom Identification
Chains can be uniquely identified using the chainID attribute (id). This is especially useful for isolating specific chains in complex systems. For example:
c.id 1: Matches the chain with ID 1.c.id 2:4, 6: Matches chains with IDs 2, 3, 4, and 6.
4. Structural Details
Structural insights often guide modeling workflows. Using attributes like numberOfResidues (c.nr), you can easily query chains with specific structural properties:
c.nr > 130: Matches chains with more than 130 residues.c.nr 100:120: Matches chains with 100 to 120 residues.
These queries can be combined with others to refine your selections further, offering unprecedented control over molecular systems.
Accessible and Flexible
One of the major strengths of SAMSON’s chain attributes is their flexibility. Since attributes can be combined, it’s possible to create specific queries tailored to your modeling needs. For example, you could search for chains that are visible, selected, and contain fewer than 50 atoms simultaneously using a single expression.
To see the full list of chain attributes and learn how to use them in your workflows, visit the original documentation page at Chain Attributes Documentation.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can download SAMSON and explore its molecular design features at www.samson-connect.net.