Antiviral Drugs Nucleoside and Nucleotide Analogs Phosphate Host cell enzyme thymidine kinase MMNV Incorporated into DNA Guanine DNA polymerase nucleotide Nucleoside (b)Synthesis of normal viral DNA guanine nucleotide Phosphate Viral enzyme thymidine kinase DNA polymerase blocked by false nucleotide.Assembly False nucleotide of DNA stops. (acyclovir triphosphate) Acyclovir (c)Synthesis of false viral DNA nucleotide with acyclovir Figure 20.16b,c Antiviral Drugs Nucleoside and Nucleotide Analogs Figure 20.16b, c