Discovery of spiro-piperidine inhibitors and their modulation of the dynamics of the M2 proton channel from influenza A virus

Jun Wang, Sarah D. Cady, Victoria Balannik, Lawrence H. Pinto, William F. DeGrado, Mei Hong

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


Amantadine has been used for decades as an inhibitor of the influenza A virus M2 protein (AM2) in the prophylaxis and treatment of influenza A infections, but its clinical use has been limited by its central nervous system (CNS) side effects as well as emerging drug-resistant strains of the virus. With the goal of searching for new classes of M2 inhibitors, a structure-activity relation study based on 2-[3-azaspiro(5,5)undecanol]-2-midazoline (BL-1743) was initiated. The first generation BL-1743 series of compounds has been synthesized and tested by two-electrode voltage-clamp (TEV) assays. The most active compound from this library, 3-azaspiro[5,5]undecane hydrochloride (9), showed an IC50 as low as 0.92 ± 0.11 μM against AM2, more than an order of magnitude more potent than amantadine (IC50 = 16 μM). 15N and 13C solid-state NMR was employed to determine the effect of compound 9 on the structure and dynamics of the transmembrane domain of AM2 (AM2-TM) in phospholipid bilayers. Compared to amantadine, spiro-piperidine 9 (1) induces a more homogeneous conformation of the peptide, (2) reduces the dynamic disorder of the G34-I35 backbone near the water-filled central cavity of the helical bundle, and (3) influences the dynamics and magnetic environment of more residues within the transmembrane helices. These data suggest that spiro-piperidine 9 binds more extensively with the AM2 channel, thus leading to stronger inhibitory potency.

Original languageEnglish (US)
Pages (from-to)8066-8076
Number of pages11
JournalJournal of the American Chemical Society
Issue number23
StatePublished - Jun 17 2009
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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