title: Design, synthesis, and evaluation of nonpeptidic inhibitors of human rhinovirus 3C protease.
abstract: The design, synthesis, and biological evaluation of reversible, nonpeptidic inhibitors of human rhinovirus (HRV) 3C protease (3CP) are reported. A novel series of 2,3-dioxindoles (isatins) were designed that utilized a combination of protein structure-based drug design, molecular modeling, and structure-activity relationship (SAR). The C-2 carbonyl of isatin was envisioned to react in the active site of HRV 3CP with the cysteine responsible for catalytic proteolysis, thus forming a stabilized transition state mimic. Molecular-modeling experiments using the apo crystal structure of human rhinovirus-serotype 14 (HRV-14) 3CP and a peptide substrate model allowed us to design recognition features into the P1 and P2 subsites, respectively, from the 5- and 1-positions of isatin. Attempts to optimize recognition properties in the P1 subsite using SAR at the 5-position were performed. In addition, a series of ab initio calculations were carried out on several 5-substituted isatins to investigate the stability of sulfide adducts at C-3. The inhibitors were prepared by general synthetic methods, starting with commercially available 5-substituted isatins in nearly every case. All compounds were tested for inhibition of purified HRV-14 3CP. Compounds 8, 14, and 19 were found to have excellent selectivity for HRV-14 3CP compared to other proteolytic enzymes, including chymotrypsin and cathepsin B. Selected compounds were assayed for antiviral activity against HRV-14-infected HI-HeLa cells. A 2.8 A cocrystal structure of derivative 19 covalently bound to human rhinovirus-serotype 2 (HRV-2) 3CP was solved and revealed that the isatin was situated in essentially the same conformation as modeled.
authors.affiliation: Agouron Pharmaceuticals, Inc., San Diego, California 92121, USA.
authors.forename: S E
authors.initials: SE
authors.lastname: Webber
authors.forename: J
authors.initials: J
authors.lastname: Tikhe
authors.forename: S T
authors.initials: ST
authors.lastname: Worland
authors.forename: S A
authors.initials: SA
authors.lastname: Fuhrman
authors.forename: T F
authors.initials: TF
authors.lastname: Hendrickson
authors.forename: D A
authors.initials: DA
authors.lastname: Matthews
authors.forename: R A
authors.initials: RA
authors.lastname: Love
authors.forename: A K
authors.initials: AK
authors.lastname: Patick
authors.forename: J W
authors.initials: JW
authors.lastname: Meador
authors.forename: R A
authors.initials: RA
authors.lastname: Ferre
authors.forename: E L
authors.initials: EL
authors.lastname: Brown
authors.forename: D M
authors.initials: DM
authors.lastname: DeLisle
authors.forename: C E
authors.initials: CE
authors.lastname: Ford
authors.forename: S L
authors.initials: SL
authors.lastname: Binford
mesh_terms: D000086042:3C Viral Proteases; D000998:Antiviral Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000187:drug effects*; D006367:HeLa Cells; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D011480:Protease Inhibitors / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D013816:Thermodynamics; D014764:Viral Proteins
chemical_list: D000998:Antiviral Agents; D011480:Protease Inhibitors; D014764:Viral Proteins; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases