Table 1. Nucleotide sequences of primers used in this study.

Primer name	Primer sequence (Nucleotide Position)
k-54	5′-CGTAAAGCACGTGAGTTAGTGCGTCGAAAAAGTGCC-3′ (1270–1305)
k-55	5′-GGCTCGAGCTAATGATGATGATGATGATGGACATCCAGGAAACGAACATCC-3′ (2013–2037)
D464N_Fw	5′-A GTG GAA GGT AAT TCG GCT GGT G
D464N_Rv	5′-C ACC AGC CGA ATT ACC TTC CAC T
N502D_Fw	5′-A GTG CTA AAG GAC ACC GAA GTT C
N502D_Rv	5′-G AAC TTC GGT GTC CTT TAG CAC T
E504V_Fw	5′-A AAG AAC ACC GTA GTT CAA GCA A
E504V_Rv	5′-T TGC TTG AAC TAC GGT GTT CTT T

Mutated codons are indicated in bold face.