title: Mechanism of inhibition of human cytomegalovirus replication by oxetanocin G.
abstract: Oxetanocin G(9-(2-deoxy-2-hydroxymethyl-beta-D-erythro-oxetanosyl)guanine, OXT-G) is a potent and selective agent against human cytomegalovirus (HCMV). In this study we synthesized the triphosphate form of OXT-G, OXT-GTP, and examined its effect on the activities of HCMV DNA polymerase, herpes simplex type 2 (HSV-2) DNA polymerase and human DNA polymerase alpha. OXT-GTP was found to inhibit all these polymerases in a competitive manner with respect to dGTP. The Km for dGTP and the Ki for OXT-GTP of HCMV DNA polymerase were 0.86 and 0.53 mu M, respectively, while the corresponding values of DNA polymerase alpha were 2.2 and 3.6 mu M, respectively. HPLC analysis using [3H]OXT-G also revealed that OXT-G was converted to its triphosphate form 7- to 8-fold more efficiently in HCMV-infected cells than in uninfected cells. The results suggest that both the preferential phosphorylation of OXT-G in HCMV-infected cells and the preferential inhibition of HCMV DNA polymerase by OXT-GTP may contribute towards the selective activity of OXT-G against HCMV replication.
authors.affiliation: Research Institute for Disease Mechanism and Control, Nagoya University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Daikoku
authors.forename: N
authors.initials: N
authors.lastname: Yamamoto
authors.forename: S
authors.initials: S
authors.lastname: Saito
authors.forename: M
authors.initials: M
authors.lastname: Kitagawa
authors.forename: N
authors.initials: N
authors.lastname: Shimada
authors.forename: Y
authors.initials: Y
authors.lastname: Nishiyama
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D003587:Cytomegalovirus / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000502:physiology; D006147:Guanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D006801:Humans; D010766:Phosphorylation; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; C057479:oxetanocin G; C068681:oxetanocin guanosine triphosphate; D006147:Guanine; D006160:Guanosine Triphosphate; D004259:DNA-Directed DNA Polymerase