TABLE 3.

Rescue of ts39 by NPH-II alleles containing alanine mutations in motifs VI

NPH-II gene	Virus titer at 40°C (PFU/ml)	Sp activity of proteina (% of wild-type activity)
		ATPase	Helicase
Wild type	8 × 106	100	100
Q491A	1 × 104	9	2
G494A	1 × 104	10	6
R495A	1 × 104	3	7
G497A	1 × 104	18	10
R498A	1 × 104	3	7
N500A	8 × 106	100	100
P501A	5 × 106	100	100
G502A	6 × 103	18	6
Plasmid	<10

^aFrom reference 9.