title: Benzothiazole and Pyrrolone Flavivirus Inhibitors Targeting the Viral Helicase.
abstract: The flavivirus nonstructural protein 3 (NS3) is a protease and helicase, and on the basis of its similarity to its homologue encoded by the hepatitis C virus (HCV), the flavivirus NS3 might be a promising drug target. Few flavivirus helicase inhibitors have been reported, in part, because few specific inhibitors have been identified when nucleic acid unwinding assays have been used to screen for helicase inhibitors. To explore the possibility that compounds inhibiting NS3-catalyzed ATP hydrolysis might function as antivirals even if they do not inhibit RNA unwinding in vitro, we designed a robust dengue virus (DENV) NS3 ATPase assay suitable for high-throughput screening. Members of two classes of inhibitory compounds were further tested in DENV helicase-catalyzed RNA unwinding assays, assays monitoring HCV helicase action, subgenomic DENV replicon assays, and cell viability assays and for their ability to inhibit West Nile virus (Kunjin subtype) replication in cells. The first class contained analogues of NIH molecular probe ML283, a benzothiazole oligomer derived from the dye primuline, and they also inhibited HCV helicase and DENV NS3-catalyzed RNA unwinding. The most intriguing ML283 analogue inhibited DENV NS3 with an IC50value of 500 nM and was active against the DENV replicon. The second class contained specific DENV ATPase inhibitors that did not inhibit DENV RNA unwinding or reactions catalyzed by HCV helicase. Members of this class contained a 4-hydroxy-3-(5-methylfuran-2-carbonyl)-2H-pyrrol-5-one scaffold, and about 20μM of the most potent pyrrolone inhibited both DENV replicons and West Nile virus replication in cells by 50%.
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: Noreena L
authors.initials: NL
authors.lastname: Sweeney
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Hanson
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: Sourav
authors.initials: S
authors.lastname: Mukherjee
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: Jean
authors.initials: J
authors.lastname: Ndjomou
authors.affiliation: Department of Microbiology, Immunology, and Pathology, 1682 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523, United States.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Geiss
authors.affiliation: Department of Microbiology, Immunology, and Pathology, 1682 Campus Delivery, Colorado State University, Fort Collins, Colorado 80523, United States.
authors.forename: J Jordan
authors.initials: JJ
authors.lastname: Steel
authors.affiliation: Specialized Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, Kansas 66047, United States.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Frankowski
authors.affiliation: Specialized Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, Kansas 66047, United States.
authors.forename: Kelin
authors.initials: K
authors.lastname: Li
authors.affiliation: Specialized Chemistry Center, University of Kansas, 2034 Becker Drive, Lawrence, Kansas 66047, United States.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Schoenen
authors.affiliation: Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States.
authors.forename: David N
authors.initials: DN
authors.lastname: Frick
keywords: ATPase; Dengue fever; West Nile virus; direct acting antiviral; motor protein; nonstructural protein 3; positive sense single-stranded RNA ((+)ssRNA) virus; yellow fever virus