Figure 5.

(A) Requirement of 3′ ssDNA tail to unwind box I substrate by UL9 protein–ICP8 complex. (I) Box I substrate with 3′ and 5′ ssDNA tails; (II) box I with a 18-nt 3′ ssDNA tail; (III) box I with ssDNA tails in opposite orientation; (IV) box I with a 18-nt 5′ ssDNA tail. UL9 protein (2 pmol) was incubated with the box I substrates, and the indicated amounts of ICP8 at 37°C for 60 min. (B) Effect of 3′ ssDNA tail length on unwinding of box I by UL9 protein–ICP8 complex. Following 15% PAGE, the ssDNA products were quantitated with a PhosphorImager.