title: Affinity of Rimantadine Enantiomers against Influenza A/M2 Protein Revisited.
abstract: Recent findings from solid state NMR (ssNMR) studies suggested that the (R)-enantiomer of rimantadine binds to the full M2 protein with higher affinity than the (S)-enantiomer. Intrigued by these findings, we applied functional assays, such as antiviral assay and electrophysiology (EP), to evaluate the binding affinity of rimantadine enantiomers to the M2 protein channel. Unexpectedly, no significant difference was found between the two enantiomers. Our experimental data based on the full M2 protein function were further supported by alchemical free energy calculations and isothermal titration calorimetry (ITC) allowing an evaluation of the binding affinity of rimantadine enantiomers to the M2TM pore. Both enantiomers have similar channel blockage, affinity, and antiviral potency.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens , Athens, Greece.
authors.forename: Antonios
authors.initials: A
authors.lastname: Drakopoulos
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens , Athens, Greece.
authors.forename: Christina
authors.initials: C
authors.lastname: Tzitzoglaki
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona , Tucson, Arizona 85721, United States.
authors.forename: Chulong
authors.initials: C
authors.lastname: Ma
authors.affiliation: Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität , D-72076 Tübingen, Germany.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Freudenberger
authors.affiliation: Department of Virology and Antiviral Therapy, Jena University Hospital , Hans Knoell Str. 2, D-07745 Jena, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Hoffmann
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona , Tucson, Arizona 85721, United States.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institut für Physikalische und Theoretische Chemie, Eberhard-Karls-Universität , D-72076 Tübingen, Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Gauglitz
authors.affiliation: Department of Virology and Antiviral Therapy, Jena University Hospital , Hans Knoell Str. 2, D-07745 Jena, Germany.
authors.forename: Michaela
authors.initials: M
authors.lastname: Schmidtke
authors.affiliation: Department of Pharmacology and Toxicology, College of Pharmacy, University of Arizona , Tucson, Arizona 85721, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens , Athens, Greece.
authors.forename: Antonios
authors.initials: A
authors.lastname: Kolocouris
keywords: Bennett’s acceptance ratio; Rimantadine enantiomers; antiviral assay; electrophysiology; free energy perturbation; influenza M2 pore; isothermal titration calorimetry; membrane protein; synthesis