title: Design and biological testing of peptidic dimerization inhibitors of human Hsp90 that target the C-terminal domain.
abstract: BACKGROUND
  Small molecules targeting the dimerization interface of the C-terminal domain of Hsp90, a validated target for cancer treatment, have yet to be identified.
  
  
  METHODS
  Three peptides were designed with the aim to inhibit the dimerization of Hsp90. Computational and biophysical methods examined the α-helical structure for the three peptides. Based on the Autodisplay technology, a novel flow cytometer dimerization assay was developed to test inhibition of Hsp90 dimerization. Microscale thermophoresis was used to determine the K(D) of the peptides towards the C-terminal domain of Hsp90.
  
  
  RESULTS
  MD simulations and CD spectroscopy indicated an α-helical structure for two of the three peptides. By flow cytometer analysis, IC(50) values of 2.08 μM for peptide H2 and 8.96 μM for peptide H3 were determined. Dimer formation of the C-terminal dimerization domain was analyzed by microscale thermophoresis, and a K(D) of 1.29 nM was determined. Furthermore, microscale thermophoresis studies demonstrated a high affinity binding of H2 and H3 to the C-terminal domain, with a K(D) of 1.02 μM and 1.46 μM, respectively.
  
  
  CONCLUSIONS
  These results revealed the first peptidic inhibitors of Hsp90 dimerization targeting the C-terminal domain. Furthermore, it has been shown that these peptides bind to the C-terminal domain with a low micromolar affinity.
  
  
  CONCLUSIONS
  These results can be used to design and screen for small molecules that inhibit the dimerization of the C-terminal domain of Hsp90, which could open a new route for cancer therapy.
authors.affiliation: Institute for Pharmaceutical and Medicinal Chemistry, PharmaCampus, Westphalian Wilhelms-University, Münster, Germany.
authors.forename: Bertan
authors.initials: B
authors.lastname: Bopp
authors.affiliation: Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Ciglia
authors.affiliation: Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Anissa
authors.initials: A
authors.lastname: Ouald-Chaib
authors.affiliation: Institute for Biochemical Plant Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Groth
authors.affiliation: Institute for Pharmaceutical and Medicinal Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany. Electronic address: Gohlke@uni-duesseldorf.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Gohlke
authors.affiliation: Institute for Pharmaceutical and Medicinal Chemistry, PharmaCampus, Westphalian Wilhelms-University, Münster, Germany. Electronic address: joachim.jose@uni-muenster.de.
authors.forename: Joachim
authors.initials: J
authors.lastname: Jose
mesh_terms: D000595:Amino Acid Sequence; D015195:Drug Design; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000502:physiology; D006801:Humans; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D017433:Protein Structure, Secondary
chemical_list: D018841:HSP90 Heat-Shock Proteins
keywords: Autodisplay; Flow cytometry; Heat shock protein 90; Molecular dynamics simulations; Protein–protein interactions