About FragmentSAR

FragmentSAR is a cheminformatics-focused web platform that integrates chemical fragments, molecules, and protein targets into a searchable and visualizable structure–activity relationship (SAR) database.

This resource supports medicinal chemistry and drug discovery workflows by providing direct links between small molecular fragments and their parent compounds, along with the biological targets they interact with. Fragments are generated using the Murcko framework approach and the BRICS fragmentation algorithm via the open-source RDKit toolkit.

Fragmentation Methods

• Murcko Scaffolds — Identifies the core ring systems and linker frameworks of molecules.
• BRICS (Breaking of Retrosynthetically Interesting Chemical Substructures) — A rule-based algorithm that decomposes molecules into chemically meaningful building blocks.

Bioactivity Data and pK_i Interpretation

• Higher pK_i values indicate stronger binding (greater potency).
• For example, a pK_i of 9 corresponds to a K_i of 1 nanomolar (nM).

Intended Use

• Fragment-based drug discovery workflows
• Structure-based SAR analysis for medicinal chemistry
• Educational and training applications in cheminformatics
• Rapid querying and visualization of molecular-fragment-target relationships

Technologies Used

Structures are rendered using RDKit. DataTables and Cytoscape.js enable rich tabular exploration and interactive network graphs. Styling is provided by Tailwind CSS.

Attributions

This platform uses publicly available chemical and bioactivity data from the ChEMBL Database and is powered by the RDKit open-source cheminformatics toolkit.