Analyze a structure-activity relationship (SAR) series by aligning scaffolds, computing descriptors, correlating structural changes with activity, and surfacing activity cliffs and driving substituents using Paramus cheminformatics tools.When to use: a user has a series of analogs with activity data and asks “what drives potency?”.Multi-tool WORKFLOW with medicinal-chemistry judgment.
Paramus — SAR Series Analysis
Overview
Given analogs + activity, find the scaffold, group by R-substitution, correlate changes with activity, and surface activity cliffs. The value is the SAR narrative, not a single descriptor call.
Guidance vs execution: alignments, matched pairs, and descriptors come from tested Paramus tools. Do not eyeball SAR from model memory — ground it in the analysis.
When to Use
- A congeneric series with measured activity and "what drives potency?"
- Identifying matched molecular pairs and activity cliffs Do not use for: de novo generation (hand off to a generative workflow).
Workflow
Analog set + activity values
↓ 1. Parse & standardize → Paramus cheminformatics tool
↓ 2. Scaffold / core detection → common core + R-group decomposition
↓ 3. Matched molecular pairs → Paramus MMP tool
↓ 4. Correlate change ↔ activity → per-substituent effect + activity cliffs
↓ 5. Report → SAR table, cliffs, driving substituents + provenance
Procedure
- Discover tools via
search/get_schema("scaffold decomposition", "matched molecular pairs"). - Standardize structures; confirm they share a core (report outliers).
- Decompose into core + R-groups; enumerate matched pairs.
- Correlate each substitution with the activity delta; flag activity cliffs (large ΔpIC50, small Δstructure).
- Report the SAR table, cliffs, and the substituents that drive/kill activity, with data provenance.
Domain Judgment
- Correlation is not causation — present trends as hypotheses to test, not mechanisms.
- Activity cliffs are the highest-information points; highlight them explicitly.
- Respect assay variability: don't over-interpret deltas within measurement noise.
Fallbacks
- MMP tool unavailable → deliver R-group + trend analysis, clearly scoped.
- Endpoint unreachable → stop and report; no local SAR heuristics.
Tools this skill may use
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Generate Atom Pair Fingerprint
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Calculate Molar Refractivity
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Used in these use cases
Customer scenarios that orchestrate this skill end-to-end.