title: Identification of ligands that target the HCV-E2 binding site on CD81.
abstract: Hepatitis C is a global health problem. While many drug companies have active R&D efforts to develop new drugs for treating Hepatitis C virus (HCV), most target the viral enzymes. The HCV glycoprotein E2 has been shown to play an essential role in hepatocyte invasion by binding to CD81 and other cell surface receptors. This paper describes the use of AutoDock to identify ligand binding sites on the large extracellular loop of the open conformation of CD81 and to perform virtual screening runs to identify sets of small molecule ligands predicted to bind to two of these sites. The best sites selected by AutoLigand were located in regions identified by mutational studies to be the site of E2 binding. Thirty-six ligands predicted by AutoDock to bind to these sites were subsequently tested experimentally to determine if they bound to CD81-LEL. Binding assays conducted using surface Plasmon resonance revealed that 26 out of 36 (72 %) of the ligands bound in vitro to the recombinant CD81-LEL protein. Competition experiments performed using dual polarization interferometry showed that one of the ligands predicted to bind to the large cleft between the C and D helices was also effective in blocking E2 binding to CD81-LEL.
authors.affiliation: Department of Chemistry, The American University in Cairo, Cairo, Egypt.
authors.forename: Reem Al
authors.initials: RA
authors.lastname: Olaby
authors.forename: Hassan M
authors.initials: HM
authors.lastname: Azzazy
authors.forename: Rodney
authors.initials: R
authors.lastname: Harris
authors.forename: Brett
authors.initials: B
authors.lastname: Chromy
authors.forename: Jost
authors.initials: J
authors.lastname: Vielmetter
authors.forename: Rod
authors.initials: R
authors.lastname: Balhorn
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry* / Q000494:pharmacology*; D001665:Binding Sites; D015195:Drug Design; D016174:Hepacivirus / Q000502:physiology*; D006526:Hepatitis C / Q000188:drug therapy; D022781:Hepatocytes / Q000187:drug effects / Q000821:virology; D054884:Host-Pathogen Interactions / Q000187:drug effects*; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D011485:Protein Binding / Q000187:drug effects; D060225:Tetraspanin 28 / Q000737:chemistry / Q000378:metabolism*; D014759:Viral Envelope Proteins / Q000378:metabolism*
chemical_list: D000998:Antiviral Agents; D008024:Ligands; D060225:Tetraspanin 28; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus