Table 2.

Rescue of ts18 by NPH-II alleles containing alanine mutations in motifs I and Ia

NPH-II geneVirus titer at 40°C (PFU/ml)Sp activity of protein (% of wild-type activity)
ATPaseHelicase
Wild type2 × 107 100100
T187A3 × 106 6852
T192A4 × 104 <0.2<1
Q194A2 × 106 5546
P228A8 × 105 9121
R229A2 × 104 2<1
Plasmid<10