title: Reverse transcriptase activity of hepatitis B virus (HBV) DNA polymerase within core capsid: interaction with deoxynucleoside triphosphates and anti-HBV L-deoxynucleoside analog triphosphates.
abstract: The use of L(-)SddC [beta-L-2',3'-dideoxy-3'-thiacytidine (lamivudine, 3TC)] for the treatment of Herpes B virus (HBV) infection is hindered by the emergence of drug-resistance associated with the L526M, L550V, and L526M/M550V mutations of the viral DNA polymerase (DP). The interactions of the anti-HBV compounds 2',3'-dideoxy-2',3'-didehydro-beta-L(-)-5-fluorode-oxycytidine and 2'-fluoro-5-methyl-beta-L-arabinofuranosyluracil triphosphate with HBV DP and its L(-)SddC-associated mutants have not been studied. The e antigen-negative variant of HBV associated with the G1896A mutation in the precore region has a high prevalence. Its effect on HBV DP is unclear. Because HBV DNA synthesis occurs in the nucleocapsid, we examined the kinetics of the reverse transcriptase activity from wild-type (wt) and mutated DPs with the wt or G1896A-mutated RNA template in the nucleocapsid. The effects of this template mutation on the activities of these L-nucleoside triphosphates were also examined. Results indicated that these DP mutations increased the Km values of deoxy-NTPs and decreased the efficiencies (Vmax/Km) of DPs. The additional L526M mutation increased the efficiency of the M550V-mutated DP but no more than that of the L526M-mutated DP. The G1896A mutation had impacts on the interactions between different DPs and deoxy-NTPs, except dCTP. It also had different impacts on the actions of the L-nucleoside triphosphates toward DPs. The L526M and M550V mutations caused a greater decrease in the Vmax using the wt RNA template compared with the G1896A-mutated template. The L526M, M550V, and L526M/M550V mutations caused varying degrees of resistance to the different M-nucleoside triphosphates.
authors.affiliation: Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
authors.forename: Wing
authors.initials: W
authors.lastname: Lam
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.forename: Jieh-Yuan
authors.initials: JY
authors.lastname: Liou
authors.forename: Ginger E
authors.initials: GE
authors.lastname: Dutschman
authors.forename: Yung-chi
authors.initials: YC
authors.lastname: Cheng
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism*; D002213:Capsid / Q000187:drug effects / Q000201:enzymology*; D002460:Cell Line; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D003845:Deoxycytosine Nucleotides / Q000378:metabolism*; D024882:Drug Resistance, Viral / Q000235:genetics; D006515:Hepatitis B virus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D009154:Mutation; D019384:Nucleic Acid Synthesis Inhibitors; D019251:Nucleocapsid / Q000235:genetics / Q000378:metabolism; D011684:Purine Nucleosides / Q000378:metabolism*; D012194:RNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use; D018411:Spodoptera
chemical_list: D000998:Antiviral Agents; D003845:Deoxycytosine Nucleotides; D019384:Nucleic Acid Synthesis Inhibitors; D011684:Purine Nucleosides; D018894:Reverse Transcriptase Inhibitors; C024107:2'-deoxycytidine 5'-triphosphate; D012194:RNA-Directed DNA Polymerase; D004259:DNA-Directed DNA Polymerase