title: Potency and Stereoselectivity of Cyclopropavir Triphosphate Action on Human Cytomegalovirus DNA Polymerase.
abstract: Cyclopropavir (CPV) is a promising antiviral drug against human cytomegalovirus (HCMV). As with ganciclovir (GCV), the current standard for HCMV treatment, activation of CPV requires multiple steps of phosphorylation and is enantioselective. We hypothesized that the resulting CPV triphosphate (CPV-TP) would stereoselectively target HCMV DNA polymerase and terminate DNA synthesis. To test this hypothesis, we synthesized both enantiomers of CPV-TP [(+) and (-)] and investigated their action on HCMV polymerase. Both enantiomers inhibited HCMV polymerase competitively with dGTP, with (+)-CPV-TP exhibiting a more than 20-fold lower apparent Ki than (-)-CPV-TP. Moreover, (+)-CPV-TP was a more potent inhibitor than GCV-TP. (+)-CPV-TP also exhibited substantially lower apparent Km and somewhat higher apparent kcat values than (-)-CPV-TP and GCV-TP for incorporation into DNA by the viral polymerase. As is the case for GCV-TP, both CPV-TP enantiomers behaved as nonobligate chain terminators, with the polymerase terminating DNA synthesis after incorporation of one additional nucleotide. These results elucidate how CPV-TP acts on HCMV DNA polymerase and help explain why CPV is more potent against HCMV replication than GCV.
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA Microbiotix Inc., Worcester, Massachusetts, USA.
authors.forename: Han
authors.initials: H
authors.lastname: Chen
authors.affiliation: Developmental Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: Chengwei
authors.initials: C
authors.lastname: Li
authors.affiliation: Developmental Therapeutics Program, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan, USA.
authors.forename: Jiri
authors.initials: J
authors.lastname: Zemlicka
authors.affiliation: Department of Pharmaceutical, Biomedical and Administrative Sciences, College of Pharmacy and Health Sciences, Drake University, Des Moines, Iowa, USA.
authors.forename: Brian G
authors.initials: BG
authors.lastname: Gentry
authors.affiliation: Microbiotix Inc., Worcester, Massachusetts, USA tbowlin@microbiotix.com don_coen@hms.harvard.edu.
authors.forename: Terry L
authors.initials: TL
authors.lastname: Bowlin
authors.affiliation: Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA tbowlin@microbiotix.com don_coen@hms.harvard.edu.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Coen
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D003521:Cyclopropanes / Q000494:pharmacology*; D003587:Cytomegalovirus / Q000187:drug effects* / Q000201:enzymology*; D004261:DNA Replication / Q000187:drug effects; D004279:DNA, Viral / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D024882:Drug Resistance, Viral / Q000235:genetics; D006147:Guanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D007700:Kinetics; D015394:Molecular Structure; D010766:Phosphorylation / Q000187:drug effects
chemical_list: D000998:Antiviral Agents; D003521:Cyclopropanes; D004279:DNA, Viral; D006147:Guanine; C495219:cyclopropavir; D004259:DNA-Directed DNA Polymerase