Metabolism and mode of action of (R)-9-(3,4-dihydroxybutyl)guanine in herpes simplex virus-infected vero cells.
The metabolism and mode of action of the anti-herpes compound buciclovir [R)-9-(3,4-dihydroxybutyl)-guanine, BCV) has been studied in herpes simplex virus-infected and uninfected Vero cells. In uninfected cells, a low and constant concentration of intracellular BCV was found, while in herpes simplex virus-infected cells, an increasing concentration of BCV phosphates was found due to metabolic trapping. The major phosphorylation product was BCV triphosphate (BCVTP) which was 92% of the total amount of BCV phosphates. BCV phosphates were accumulated to the same extent in cells infected with either a herpes simplex virus type 1 or a herpes simplex virus type 2 strain while thymidine kinase-deficient mutants of herpes simplex virus type 1 were 10 times less efficient in accumulating BCV phosphates. In uninfected Vero cells, the concentration of the phosphorylated forms of BCV was less than 1% of that found in herpes simplex virus-infected cells. The BCVTP formed in herpes simplex virus-infected cells was highly stable, as 80% of the amount of BCVTP was still present even 17 h after removal of extracellular BCV. BCV was a good substrate for herpes simplex virus type 1- and type 2-induced thymidine kinases but not for the cellular cytosol or mitochondrial thymidine kinases. BCV monophosphate could be phosphorylated by cellular guanylate kinase to BCV diphosphate. BCVTP was a selective and competitive inhibitor to deoxyguanosine triphosphate of the purified herpes simplex virus type 1- and type 2-induced DNA polymerases. BCVTP could neither act as an alternative substrate in the herpes simplex virus type 2 or cellular DNA polymerase reactions, nor could [3H]BCV monophosphate be detected in DNA formed by herpes simplex virus type 2 DNA polymerase, or be detected in nucleic acids extracted from herpes simplex virus type 1-infected cells. These data indicate that BCVTP may inhibit the herpes simplex virus-induced DNA polymerase without being incorporated into DNA.
Stenberg
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K
Larsson
A
A
Datema
R
R
D000212:Acyclovir / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism* / Q000494:pharmacology; D001692:Biological Transport; D002460:Cell Line; D002522:Chlorocebus aethiops; D003600:Cytosol / Q000201:enzymology; D004247:DNA / Q000096:biosynthesis; D051528:Guanylate Kinases; D007668:Kidney; D008928:Mitochondria / Q000201:enzymology; D019384:Nucleic Acid Synthesis Inhibitors; D009703:Nucleoside-Phosphate Kinase / Q000378:metabolism; D010766:Phosphorylation; D012313:RNA / Q000096:biosynthesis; D018139:Simplexvirus / Q000187:drug effects*; D013379:Substrate Specificity; D013937:Thymidine Kinase / Q000378:metabolism; D014764:Viral Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism
D000998:Antiviral Agents; D019384:Nucleic Acid Synthesis Inhibitors; D014764:Viral Proteins; C037591:buciclovir; D012313:RNA; D004247:DNA; D013937:Thymidine Kinase; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases; D000212:Acyclovir