Structure-based discovery of prescription drugs that interact with the norepinephrine transporter, NET

Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):15810-5. doi: 10.1073/pnas.1106030108. Epub 2011 Sep 1.


The norepinephrine transporter (NET) transports norepinephrine from the synapse into presynaptic neurons, where norepinephrine regulates signaling pathways associated with cardiovascular effects and behavioral traits via binding to various receptors (e.g., β2-adrenergic receptor). NET is a known target for a variety of prescription drugs, including antidepressants and psychostimulants, and may mediate off-target effects of other prescription drugs. Here, we identify prescription drugs that bind NET, using virtual ligand screening followed by experimental validation of predicted ligands. We began by constructing a comparative structural model of NET based on its alignment to the atomic structure of a prokaryotic NET homolog, the leucine transporter LeuT. The modeled binding site was validated by confirming that known NET ligands can be docked favorably compared to nonbinding molecules. We then computationally screened 6,436 drugs from the Kyoto Encyclopedia of Genes and Genomes (KEGG DRUG) against the NET model. Ten of the 18 high-scoring drugs tested experimentally were found to be NET inhibitors; five of these were chemically novel ligands of NET. These results may rationalize the efficacy of several sympathetic (tuaminoheptane) and antidepressant (tranylcypromine) drugs, as well as side effects of diabetes (phenformin) and Alzheimer's (talsaclidine) drugs. The observations highlight the utility of virtual screening against a comparative model, even when the target shares less than 30% sequence identity with its template structure and no known ligands in the primary binding site.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Amino Acid Sequence
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Binding Sites / genetics
  • Biological Transport / drug effects
  • Computational Biology / methods
  • Drug Discovery / methods*
  • HEK293 Cells
  • Humans
  • Kinetics
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Structure
  • Norepinephrine / chemistry
  • Norepinephrine / metabolism
  • Norepinephrine / pharmacokinetics
  • Norepinephrine Plasma Membrane Transport Proteins / chemistry*
  • Norepinephrine Plasma Membrane Transport Proteins / genetics
  • Norepinephrine Plasma Membrane Transport Proteins / metabolism
  • Plasma Membrane Neurotransmitter Transport Proteins / chemistry
  • Plasma Membrane Neurotransmitter Transport Proteins / genetics
  • Plasma Membrane Neurotransmitter Transport Proteins / metabolism
  • Prescription Drugs / chemistry*
  • Prescription Drugs / metabolism
  • Prescription Drugs / pharmacology
  • Protein Binding
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid


  • Bacterial Proteins
  • Norepinephrine Plasma Membrane Transport Proteins
  • Plasma Membrane Neurotransmitter Transport Proteins
  • Prescription Drugs
  • SLC6A16 protein, human
  • SLC6A2 protein, human
  • Norepinephrine