June 2026

Model Performance Series

Illustration of a Happy Protein with Its PTMs

Astra AI on Transporters

Membrane transporters move ions, nutrients, and drugs across the lipid bilayer — among the most under-exploited drug-target classes, and among the hardest to characterize: folds vary widely, many shift between conformations, and a sizable subset are themselves enzymes. This report shows how Orbion's Astra AI Suite characterizes them from sequence alone — function, topology, PTM sites, binding pockets, and thermostability — measured against public experimental ground truth across 6,203 transport-associated proteins.


  • 0.95 AUROC Topology

  • 56% Ligand Recall

  • ρ=0.59 ΔTm (SERT)

Illustration of a Happy Protein with Its PTMs

97% Recognition Across the Canonical Transporter Families

SLC carriers 97%, ABC transporters and aquaporins 100% recognized as transporters. The broad keyword also captures enzymatic ATPases and trafficking GTPases, which the model routes to their true function rather than averaging away — and residue-level topology stays strong across every family (AUROC 0.94–0.98).

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

F1 Up to 0.88 on PTM Site Prediction

Per-residue sites across 39 classes; strongest on disulfide bonds (0.88) and N-linked glycosylation (0.83) — the modifications that govern folding and surface trafficking of multi-pass carriers.

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

ρ=0.59 ΔTm Ranking on SERT

On 197 mutations of the serotonin transporter, the suite ranks by predicted ΔTm at ρ 0.59, MAE 2.13 °C, 81% directional on strong stabilizers. It compresses extreme-magnitude effects (shown honestly) — the value is correct ranking before a thermal-shift screen.

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

Have a question?

Whether you want to understand our models, test a specific protein, or just ask how Orbion applies to your research — send us your question and we'll get back to you. Or, if you'd prefer a live walkthrough, book a demo.