June 2026

Model Performance Series

Illustration of a Happy Protein with Its PTMs

Astra AI on Ion Channels

Ion channels are among the most consequential — and treacherous — classes in drug discovery: validated targets across pain, epilepsy, and arrhythmia, home to the hERG cardiac anti-target, and structurally diverse, with drug sites buried in the conduction pathway. This report shows how Orbion's Astra AI Suite characterizes them from sequence alone — function, topology, PTM sites, and ligand/pore-block pockets — measured against public experimental ground truth across 2,700 ion-channel proteins.


  • 0.97 AUROC Topology

  • 56% Ligand Recall

  • F1 Up to 0.90 for PTMs

Illustration of a Happy Protein with Its PTMs

0.97 AUROC on TM Topology, Single-pass to 24-TM Giants

Per-residue TM prediction agrees with UniProt at AUROC 0.97 (AUPRC 0.91, F1 0.87) across the full topological range. The 24-TM voltage-gated Ca²⁺ channels are the hardest (0.82).

Orbion's AstraPTM2 Machine Learning Model's PTM Predictions on an Example Protein

Recovers Known hERG Pore Blockers

The 56% aggregate masks the result that matters — a clean biological split. On ligand-gated channels the model localizes the pocket well; on voltage-gated channels including the hERG safety case it recovers the ligand identity (the worked example recovers E4031, BeKm-1, ErgTx-1) but the pore-block site is structurally diffuse — read the panel as a ligand hypothesis set, not a residue-contact map.

Orbion's AstraPTM2 Machine Learning Model's PTM Predictions on an Example Protein

F1 Up to 0.90 on PTM Site Prediction

Per-residue sites across 39 classes; strongest on disulfide bonds (0.90) and N-linked glycosylation (0.88) — the extracellular modifications that govern channel folding and surface expression.

Orbion's AstraPTM2 Machine Learning Model's PTM Predictions on an Example Protein

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