PROTAC Linker Design: A No-Code Workflow for Degrader Chemistry
How to generate and evaluate PROTAC linkers — connecting a target-binding warhead to an E3 ligase ligand — using ChemOrchestra's Linker Design tool.
Jul 18, 2026
Application
PROTACs & radionuclide drug linkers
Input
Warhead + ligase ligand
Output
Candidate linker structures
Why linker design is the hard part of PROTAC development
A PROTAC works by holding a target protein and an E3 ubiquitin ligase close enough together to form a ternary complex, so the ligase tags the target for degradation. The warhead and the E3 ligand are often known quantities — the linker connecting them is what actually determines whether that ternary complex forms efficiently. Linker length, flexibility, and attachment geometry all affect whether the two proteins can actually come together in a productive orientation, which is why linker design is frequently the rate-limiting step in getting a degrader to work at all.
How ChemOrchestra generates linker candidates
The Linker Design tool takes your warhead structure and E3 ligase ligand as inputs and generates candidate linker structures connecting them. Because it runs as a workflow node, you can feed the output directly into downstream evaluation steps — geometry optimization or a docking check — without leaving the workflow canvas.
Evaluating candidates before synthesis
Not every generated linker is worth synthesizing. Screen candidates by feasible chemistry (is the linker actually synthesizable with standard chemistry), predicted geometry (does the resulting molecule plausibly support ternary complex formation), and ADMET properties (a PROTAC's larger molecular weight already works against typical drug-likeness, so linker choice matters for developability too) before committing to synthesis.
Beyond PROTACs: radionuclide drug linkers
The same linker-design problem shows up in radionuclide therapeutics, where a targeting ligand needs to be connected to a chelator carrying a radioactive payload instead of to an E3 ligase ligand. ChemOrchestra's Linker Design tool supports this use case as well — the underlying challenge of connecting two functional groups with a linker that doesn't interfere with either one's activity is the same problem in a different therapeutic modality.