Chemistry Space

SAR Analysis

Structure–Activity Relationship (SAR) analysis explains whya series of molecules is more or less potent. Wawe's explainable SAR takes a set of compounds with measured activities and attributes potency to specific substructures — so you can see which chemical changes drive the signal, not just that a signal exists.

Input format

Provide one compound per line as SMILES, activity. Activity is typically pIC50, pKi, or pEC50 (higher = more potent). A minimal example:

O=C(N)c1ccccc1, 5.0
O=C(N)c1ccc(Cl)cc1, 6.5
O=C(N)c1ccc(Br)cc1, 6.9
O=C(N)c1ccc([N+](=O)[O-])cc1, 7.8
O=C(N)c1ccc(C)cc1, 5.2

A useful series shares a common scaffold and varies at one or two positions — that's what lets the model isolate the effect of each substituent.

Reading the output

• Atom contributions — Each atom is shaded by how much it pushes activity up (green) or down (red).
• Fragment ranking — Substructures ranked by their average contribution across the series.
• Activity cliffs — Pairs of near-identical molecules with large activity gaps are flagged.

From insight to next molecule

SAR analysis is a design loop, not a one-shot report. Once you know which fragment carries potency, hand it back to Chemistry Space to enumerate analogues, predict their ADMET, and screen the promising ones at the Work Station.

Limitations

Attributions are only as good as the series. Sparse or noisy activity data, mixed assay conditions, or scaffolds that differ too much will weaken the explanation. Treat contributions as hypotheses to test, not ground truth.