Research-informed screening strategy

Fragment-Based Virtual Screening Services: Find Small, Efficient Starting Points

Fragment screening explores chemical space with low-molecular-weight compounds that can reveal tractable interactions in shallow, novel, or underexplored pockets. Our workflow emphasizes pose quality, ligand efficiency, three-dimensional diversity, growth vectors, and practical paths from a fragment hit to a testable series.

Discuss your project Choose a screening route

Fragment-based virtual screening and fragment growth analysis in a protein pocket

Problems this service solves

Turn an Uncertain Search into a Defined Decision

Every project is scoped around the scientific uncertainty, the available evidence, and the number of candidates your team can validate.

Conventional libraries do not fit a small or shallow pocket

Use compact, diverse fragments to sample interactions that larger molecules may miss.

A project needs a ligand-efficient starting point

Prioritize simple binders with interpretable interactions and room for optimization.

A covalent or hotspot strategy is being considered

Screen electrophile-aware or hotspot-focused subsets with target-residue and reactivity constraints.

Start from your pocket and experimental plan

Can We Support Your Fragment Screening Project?

Match your current evidence to the fragment workflow we can build and the decision-ready outputs your team will receive.

Your Starting Point	You Provide	We Build	You Receive
A qualified but shallow, novel, or underexplored pocket	Target structure or model Pocket location and biological context Key residues, waters, metals, or cofactors Available assay and test capacity	Pocket and hotspot assessment Fragment-library selection and preparation Fragment-aware docking and expanded sampling Pose, strain, interaction, and efficiency review	Ranked, diverse fragment set Binding poses and anchor interactions Ligand-efficiency metrics Experimental confirmation plan
An accessible nucleophilic residue and a covalent strategy	Reactive residue and structural context Permitted warheads or exclusions Reactivity and selectivity constraints Preferred covalent library	Geometry and residue-accessibility review Electrophile-aware library curation Covalent pose generation Noncovalent recognition and liability triage	Covalent fragment shortlist Reaction-compatible binding hypotheses Warhead and selectivity flags Suggested confirmation sequence
One or more experimental fragment hits need optimization	Hit structures and measured data Co-complex or competition evidence, if available Property and chemistry constraints Desired optimization objective	Hit-pose and interaction review Adjacent subpocket mapping Fragment growing, linking, or merging analysis Analog and purchasability search	Growth-vector map Prioritized elaboration ideas Matched analog candidates Testable fragment-to-lead plan
A fragment library must be reduced to an assayable set	Library SDF/SMILES or vendor source Target structure and site definition Solubility, complexity, and assay limits Desired shortlist size	Quality, PAINS, and reactivity filtering 3D conformer and protonation preparation Structure-based ranking Diversity and availability selection	Procurement-ready test set Cluster and diversity report Pose and property evidence Primary candidates and backups

Minimum starting point: a credible target structure with a defined pocket and a practical fragment-confirmation method. Where pocket readiness or assay sensitivity is uncertain, we can begin with a feasibility assessment.

Illustrative result package

See What a Fragment Screening Project Delivers

The output connects pocket evidence, fragment efficiency, binding geometry, chemical diversity, and clear opportunities for growing, linking, or experimental confirmation.

Pocket & Hotspots Fragment Library Pose Review Efficiency & Diversity Test Set & Growth Map

Explain Why a Fragment Was Prioritized

Each recommendation is tied to an interpretable interaction and an optimization path.

Anchor quality: conserved hydrogen bonds, ionic contacts, metal coordination, or hotspot occupancy.
Fragment quality: size, strain, three-dimensionality, solubility, and undesirable reactivity.
Efficiency: score or affinity normalized to fragment size, interpreted with uncertainty.
Growth potential: solvent-exposed vectors and adjacent subpockets that can support elaboration.

Move from a Hit List to a Test Plan

The report separates plausible binders from compounds that are merely small or highly scored.

Primary fragments and chemically diverse backups
Pose files and residue-level interaction maps
Growth, linking, or merging opportunities
Recommended biophysical, structural, or biochemical confirmation

Example Fragment Candidate Shortlist

Illustrative fields show how efficiency, binding evidence, properties, and optimization potential are reviewed together.

Illustrative data

Priority	Fragment ID	Docking Score	Ligand Efficiency	MW	Key Anchor	Growth Vector	Decision
01	FRG-104	-7.2	0.43	184	Asp H-bond	Subpocket B	Advance
02	FRG-218	-6.9	0.41	176	Metal contact	Solvent channel	Advance
03	FRG-327	-7.5	0.38	207	Tyr stacking	Subpocket A	Advance
04	FRG-451	-6.7	0.40	169	Water bridge	Two vectors	Review
05	FRG-566	-7.8	0.35	231	Hydrophobic hotspot	Limited	Review
06	FRG-642	-6.5	0.39	173	Lys ionic contact	Subpocket C	Review
07	FRG-735	-7.1	0.31	246	Pose uncertain	One vector	Hold
08	FRG-829	-6.8	0.34	221	Weak polar match	Occluded	Hold

Interpretation note: docking scores and ligand-efficiency estimates prioritize hypotheses; they do not establish fragment binding. Weak fragment interactions should be confirmed with suitably sensitive biophysical or structural methods.

Research applications

Where This Screening Strategy Creates Value

The method is selected for the scientific decision—not used as a one-size-fits-all calculation.

Shallow-Pocket Discovery

Probe compact interaction hotspots where conventional lead-like molecules perform poorly.

Novel Target Entry

Generate minimal starting points when few ligands or SAR data are available.

Covalent Fragment Screening

Prioritize fragments compatible with an accessible nucleophilic residue and a controlled electrophile strategy.

PPI and Allosteric Sites

Identify small anchors within protein–protein interfaces or regulatory pockets.

Fragment Growing

Map vectors that can extend a validated fragment toward adjacent subpockets.

Fragment Linking and Merging

Assess whether nearby or overlapping fragments can be combined into higher-affinity designs.

Decision-gated workflow

From Project Question to Experiment-Ready Shortlist

Assess pocket tractability

Map hotspots, key waters, subpockets, residue chemistry, and whether fragment binding can be detected experimentally.
Select the library

Choose general, 3D, soluble, covalent, or focused fragment collections and apply appropriate quality rules.
Run fragment-aware docking

Use expanded sampling and interaction-focused scoring suited to weak, low-complexity ligands.
Inspect and cluster poses

Remove strained or implausible orientations and identify recurring anchors and chemotypes.
Map optimization vectors

Highlight accessible directions for growing, linking, or merging while preserving the core interaction.
Nominate a test panel

Deliver a diverse set with efficiency metrics and recommended biophysical or structural follow-up.

Quality gates

Three Checks Before a Candidate Is Recommended

Gate 01

Input Fitness

Are the structure, ligand data, target panel, and library suitable for the chosen method?

Gate 02

Evidence Convergence

Do orthogonal scores, interactions, chemistry, and biological context support the same candidates?

Gate 03

Experimental Actionability

Can the shortlist be sourced, tested, interpreted, and used to make the next program decision?

Defined outputs

Deliverables Built for the Next Experimental Decision

Files, evidence, and recommendations are organized so your team can review the selection logic and move candidates into testing.

Fragment Shortlist

Ranked fragments
Diversity clusters
Availability data

Binding Hypotheses

Pose files
Hotspot interactions
Water and residue context

Optimization Map

Growth vectors
Linking options
Efficiency metrics

Validation Plan

Assay sequence
Controls
Structural follow-up

Related screening methods

Choose the Evidence Route That Matches Your Project

Methods can be used alone or combined as a consensus workflow when the inputs and decision justify it.

FAQs

Frequently Asked Questions

Fragments are smaller and often weaker binders, so the workflow places more weight on interaction quality, ligand efficiency, pose plausibility, solubility, and downstream growth potential.

Yes. The project must define the target residue, acceptable electrophile classes, selectivity concerns, and the experimental assay needed to distinguish specific engagement from nonspecific reactivity.

The answer depends on pocket quality, library diversity, assay capacity, and desired chemical coverage. We design the shortlist around the experimental platform rather than a fixed universal number.

Yes. Growth vectors, adjacent subpockets, key interactions, and potential linking or merging hypotheses can be included in the final package.