FIGURE 7.

The N239Y substitution leads to higher caspase 3 activity. H1299 cells were transfected with EGFP-tagged p53 plasmid. Caspase 3 activity was measured after 24 h, and normalized for cell numbers using a cell viability kit in a parallel experiment. Higher caspase activity could be traced back to a single N239Y mutation (N239Y mutation is also present in QM-V143A, QM, and HM). Comparison with the QM V143A and N268D controls showed that the higher caspase 3 activity in N239Y was not due to its higher thermodynamic stability.