FIG. 5.
EBV-PK, like CDK2/cyclin A, inhibits DNA helicase (unwinding) activity associated with the MCM4-6-7 complex. (A) Substrate for DNA helicase assays. A 5′ 32P-labeled oligonucleotide (17-mer) annealed to M13 single-stranded DNA is depicted. (B) DNA helicase assays were performed with 100 fmol of the helicase substrate and human MCM4-6-7 hexamers (100 ng) in the presence of cyclin A/CDK2 (100 ng), BGLF4 protein (100 and 500 ng), or kinase-negative BGLF4K102I protein (200 and 500 ng) as described in Materials and Methods. Positions of the DNA substrate (17mer/M13) and displaced oligonucleotide (17mer) are indicated by arrows. The left two lanes show results for heat-denatured and native DNA substrates, respectively.