Azt and valaciclovir are antiviral nucleoside analogs that interfere with "nucleic acid synthesis".Nucleic acids are framed when nucleotides meet up through phosphodiester linkages between the 5' and 3' atoms of carbon. A Nucleic corrosive arrangement is the arrangement of nucleotides inside a DNA (GACT) or RNA (GACU) atom that is controlled by a progression of letters.