Figure 3.

Effect of salt on DNA binding and kinase activities of p460 and Ku–p460 complexes. (A) Increasing salt disrupts DNA binding of p460 but not of Ku. Labeled f32 DNA (0.2 ng) was incubated with Ku (11 ng), p460 (35 ng), or an equimolar mixture of both in 5 μl of buffer B containing various concentrations of NaCl and analyzed by EMSA. (B) Increasing salt inhibits kinase activity strongly for p460 and weakly for Ku–p460 complexes. Kinase activities of p460 or the Ku–p460 complex were measured after stimulation by f32 DNA (0.2 ng) in buffer C containing various concentrations of NaCl by using the same protein concentrations as in A.