Cyanobacterial peptides as a prototype for the design of potent β-secretase inhibitors and the development of selective chemical probes for other aspartic proteases

J Med Chem. 2012 Dec 13;55(23):10749-65. doi: 10.1021/jm301630s. Epub 2012 Nov 26.


Inspired by marine cyanobacterial natural products, we synthesized modified peptides with a central statine-core unit, characteristic for aspartic protease inhibition. A series of tasiamide B analogues inhibited BACE1, a therapeutic target in Alzheimer's disease. We probed the stereospecificity of target engagement and determined additional structure-activity relationships with respect to BACE1 and related aspartic proteases, cathepsins D and E. We cocrystallized selected inhibitors with BACE1 to reveal the structural basis for the activity. Hybrid molecules that combine features of tasiamide B and an isophthalic acid moiety-containing sulfonamide showed nanomolar cellular activity. Compounds were screened in a series of rigorous complementary cell-based assays. We measured secreted APP ectodomain (sAPPβ), membrane bound carboxyl terminal fragment (CTF), levels of β-amyloid (Aβ) peptides and selectivity for β-secretase (BACE1) over γ-secretase. Prioritized compounds showed reasonable stability in vitro and in vivo, and our most potent inhibitor showed efficacy in reducing Aβ levels in the rodent brain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyloid Precursor Protein Secretases / antagonists & inhibitors*
  • Aspartic Acid Proteases / chemistry*
  • Cyanobacteria / chemistry*
  • Drug Design
  • Models, Molecular
  • Molecular Probes
  • Peptides / chemistry*
  • Peptides / pharmacology*
  • Protease Inhibitors / chemistry*
  • Protease Inhibitors / pharmacology*
  • Spectrometry, Mass, Electrospray Ionization
  • Structure-Activity Relationship


  • Molecular Probes
  • Peptides
  • Protease Inhibitors
  • Amyloid Precursor Protein Secretases
  • Aspartic Acid Proteases

Associated data

  • PDB/3UQP
  • PDB/3UQR
  • PDB/4DV9
  • PDB/4DVF
  • PDB/4FGX